Made my own resistance solder unit
JCunington
Given my luck with electrical stuff when I don't know what the heck I'm doing,
the darn thing actually works!
I used a 12V 5A transformer as the base for it (American Science & Surplus,
$10; they also have a 12V 10A xformer). Also from AS&S, 1/4" graphite rod ($1)
and a foot switch ($1.50). From Radio Shack, banana plugs (male and female),a
fuse holder, and 1A fuses. You'll need some brass bar stock (K&S, about $1.69),
two 3/8"-7/8" automotive hose clamps ($2), two brass gas line couplings ($.75
each), and some 16 ga. line cord. Also some 3/4" dowel for insulators on the
handles.
The basic wiring is this: On the transformer primary, attach one wire from the
wall socket to the transformer. The other wire goes to the fuse holder. The
second wire on the fuse holder will go to the foot switch. The return wire
from the foot switch goes to the transformer primary. The secondaries get
hooked to electrical sockets for the banana plugs.
I made a tweezer type attachment for expediency. Cut off about 6 inches of bar
stock. Find the midpoint and bend it into a lazy U-shape. Take the dowel. Cut
off two sections about 4 inches long. Drill a hole lengthwise down the middle
of the dowels of sufficient diameter to feet the wire through. Drill a hole at
one end for the brass gas line couplings to fit in. Drill your gas line
couplings out to a sufficient diameter to hold your graphite rod (mine was
1/4"; 1/8" arc-welding electrode works also). Feed the handle wires through the
dowels. Solder the ends to the couplings, then epoxy the couplings into the
handles. On my handles the graphite rod is a press fit, so no retainer screws
are needed. At the other end of the handle wires, solder the male banana plugs
on.
That's all there is to it. I found I can solder two pieces together with about
3 seconds of current. It works like a charm. Not bad for $25.
Now before anyone who has the multi-hundred dollar commercial units starts with
the "You have to have less than 6 volts." routine, mine works fine. I'm
satisfied with it. It works. You can do it yourself. There are web sites out
there (don't ask me, I didn't save them on my browser) to show you how with
more explanation than I've provided here.
Now to build some turnouts...
Bill
Thanks, Jay. Now I can make one, too!
Bill
Bill's Railroad Empire
N Scale Model Railroad:
http://www.billsrailroad.net
Brief History of N Scale:
http://www.billsrailroad.net/history/n-scale
Resources: Links to over 300 helpful sites:
http://www.billsrailroad.net/bills-favorite-links
Bookstore: http://www.billsrailroad.net/bookstore.html
Trainman
JCunington <jcuni...@aol.com> wrote in message
news:20021110172247...@mb-ms.aol.com...
Jay is right. I saw it work today! I just may be building one myself.
Don
--
don.de...@prodigy.net
http://www.geocities.com/don_dellmann
moderator: WisMode...@yahoogroups.com
moderator: MRP...@yahoogroups.com
http://www.yahoogroups.com/group/MRPics
JCunington
not!!!), let me set you straight. I cadged this idea from another guy's web
site. He had a thing about grabbing a transformer out of a microwave and
rewinding the secondary using 8 gauge wire. That's a bit heavy duty for our
purposes. I was in American Science & Surplus one day last summer and saw the
transformers for sale (still some left!). I thought 5 amps might be a little
light, but I'd try it and see what happens. Turns out it works. It does tend to
blow 1 amp fuses if I stay on the switch too long. I'm putting in a 2 amp and
I'll see how that works. I think this same web site said he runs it unfused,
relying on the normal magnetic impedance (or something) in the transformer to
keep it from melting down. With a duty cycle of 4-5 seconds max it doesn't
really have time to go into meltdown mode, so if you drive your transformer at
double the normal current, don't sweat it (according to the author).
My next step is to get some more wire and build a probe and alligator clamp set
up for this thing.
I've seen resistance soldering now and I LIKE IT!!! I see some brass
locomotives in my future, and that ain't Madam Zelda talking.
Charlie
I am sleeping at the switch.
I don't understand where the brass bar stock (bent into a 'U') goes, or how
it is hooked up.
....Does one of the 'gas line fittings' get soldered to the bar stock, and
then the 2nd dowel epoxied to it?
What size is the brass bar stock?
How do the hose clamps participate?
.....thanks for a great idea...charlie
***************************************************************
JCunington <jcuni...@aol.com> wrote in message
news:20021110172247...@mb-ms.aol.com...
Sven
<http://www.trainweb.org/girr/tips/tips1/solderer.pdf>
As you can see, it's in pdf format.
Steve Caple
> How do the hose clamps participate?
Here's an excellent article on building your own resistance unit. It
actually has diagrams!
<http://www.cox-internet.com/drspiff/electronics/resistance.htm>
--
Steve
Charlie
**********************************************
Charlie <footb...@peoplepc.com> wrote in message
news:usuv2k...@corp.supernews.com...
Bob May
one that has an output plug on it so you don't have to worry about wiring it
up and you will have a good complete resistance iron.
--
Bob May
Global WARMING???
What I want to know is when I can start growing wheat in Greenland again!
JCunington
>it is hooked up.
>....Does one of the 'gas line fittings' get soldered to the bar stock, and
>then the 2nd dowel epoxied to it?
>What size is the brass bar stock?
>How do the hose clamps participate?
OK, take two, and I'll see if I can do a better job this time.
The brass bar stock (about 3/8" X 1/8"; not critical) gets bent into a U shape
to form the spring for the tweezers. The two dowels will be clamped to each
side of the U with the hose clamps. The bottom of the dowels (the open end of
the tweezers) will be drilled to accept the gas fittings. The dowel will be
drilled through to accept the lamp cord or wire. The wire gets passed through
the small hole to the bottom of the dowel. The wires then get soldered to the
brass fitting. The brass fittings then get pulled back into the large holes in
the dowels and epoxied in. So you end up with a pair of wood-handled tweezers
with brass contacts to hold the graphite rods.
Jay
Gerry Leone
This idea kicks butt!! I have a few questions, tho:
> I made a tweezer type attachment for expediency. Cut off about 6 inches of
bar
> stock. Find the midpoint and bend it into a lazy U-shape. Take the dowel.
Cut
I'm not certain what you mean by this. Do you then solder one of the wires
to this bar stock?
> one end for the brass gas line couplings to fit in. Drill your gas line
Where do you find these? Auto parts store?
I'd love to see a photo of this, since I'm just not clear about the brass
bar stock thing. But this is a tremendous idea... and the price is really
right!
-Gerry Leone
http://home.earthlink.net/~gerryleone/trains.htm
JCunington
>I'm not certain what you mean by this. Do you then solder one of the wires
>to this bar stock?
>
NO!!!!!! The bar stock is ONLY a spring for the tweezer attachment. If you
prefer the probe and clamp type of set-up, forget the tweezer thing. The wires
go into the holes drilled down the length of the dowel (which is the insulated
handle) and out the other end.
>> one end for the brass gas line couplings to fit in. Drill your gas line
>
>Where do you find these? Auto parts store?
These fittings have a thread that would screw into a 3/4"-1" ID gas line
coupling (standard plumbing thread) and reduce it down to a 1/2" or 5/8" OD.
There is a small orifice at the narrow end that I drilled out to fit my
graphite rod. Probably 1/8" graphite arc welding electrode would fit it. Check
your hardware store. It's a gas fitting that goes from a big pipe to a little
one - it's an adapter of some sort. Got mine at American Science and Surplus
for 75 cents each.
There's a drawing of the tweezer about halfway down this page:
http://www.tyler.net/drspiff/electronics/resistance.htm
Here are more instructions for building one. This site and the one above are
the instructions I followed.
http://www.trainweb.org/bristol-s-gauge/Projects/rsu.html
Here's a page demonstrating use of the tool:
http://www.bdsonline.net/brunelmodels/soldering/rstalk.htm
Build your own and save save save!
Jay
KTØT
wire foam cutters. It sounds like the same could be used for the resistance
solderer.
--
73 de KTØT
Bob Schwartz
Modeling Waseca, MN in the 50s
: There's a drawing of the tweezer about halfway down this page:
JCunington
>wire foam cutters. It sounds like the same could be used for the resistance
>solderer.
>
It can be done and there are instructions on the web. I haven't seen them, but
others have referred to their existence.
Jay
Aredeer
>bar
>> stock. Find the midpoint and bend it into a lazy U-shape. Take the dowel.
>Cut
Easier,
Get a set of bamboo tongs from one of the " Dollar" stores, you have an
insulated tool with the springing action you need, and attach a probe to each
arm ( use your imagination).
B.Get an aluminum plate, attach the -lead to it with a clamp, lay the object(s)
on it to be soldered, touch with the +probe...done!.
Gerry Leone
talked to has nothing but good things to say about it.
So here's my questions: I've already got a battery charger that has a
setting for 6v 9amps -- perfect! But I don't want to have to buy a new
battery charger.
Could I make a set of terminals that the charger plugs into, so that the
soldering apparatus plugs into them when I'm soldering, and the big battery
terminal clips plugs into them when I'm charging the battery? Or am I
introducing too much resistance/too many connections into the system?
And if I do use the battery charger, do I want the setting on "high charge"
or "trickle" or does it matter?
--
-Gerry Leone
http://home.earthlink.net/~gerryleone/trains.htm
KTØT
impact on the connectors you should use.
A thought -- how about making an "interface board" that had a couple of
bolts big enough for the battery clamps to clamp on to? Then connect your
new resistance soldering tools to those bolts; that way you don't have to
mess up the integrity of the high current circuit.
BTW, I found a nice Variac at Dexus a few years ago; if they still have one,
it would be an ideal addition for better heat control.
--
73 de KTØT
Bob Schwartz
Modeling Waseca, MN in the 50s
"Gerry Leone" <gerry...@earthlink.net> wrote in message
news:gyhB9.89$_6.1...@newsread1.prod.itd.earthlink.net...
: Now I'm really jazzed on this resistance soldering idea. Everyone I've
:
:
Gerry Leone
> A thought -- how about making an "interface board" that had a couple of
> bolts big enough for the battery clamps to clamp on to? Then connect your
> new resistance soldering tools to those bolts; that way you don't have to
> mess up the integrity of the high current circuit.
Great idea!
> BTW, I found a nice Variac at Dexus a few years ago; if they still have
one,
> it would be an ideal addition for better heat control.
I'll keep my eyes peeled for this. Thanks.
Tim Moran
I've really enjoyed this discussion about a DIY resist unit! I'm ready to take
to plunge except for one little matter...I have a Variac (Adjust a Volt brand)
and don't know how to proceed from this point.
Are there some special connections that need to be made on the Variac? I have 7
"screw down" terminals on the side of this unit and only 3 are used (neutral
wires are sharing a terminal).
Any "constructive" advise on this matter would be appreciated.
Thanks in advance!
Tim
Lawrence Costa
>Snip
Please, Please. If anyone is thinking about using just a variac,
DON'T. Its fine to put one in the primary circuit of a transformer or
battery charger but don't use just the variac to feed the electrodes.
Too much voltage and a shock danger.
Larry
KTØT
It's hard to guess what the terminals are on your Variac so I'll give you an
idea how they work and maybe you can go from there.
First, be very careful because you are working with house current -- which
can kill! If you have any doubt, maybe you can find a friendly electrician
or ham that could help you. Again, BE CAREFUL.
Now:
First of all, a Variac is a transformer with only one winding; the input
goes to the full transformer and the output is tapped off by a slider.
Variacs provide NO isolation between input and output. We're used to train
transformers which usually are real transformers with separate input and
output windings so the output is safe.
Two terminals go to the transformer and are to be connected to 110 VAC.
I suggest that you connect a fuse (perhaps 5 amps) between one of the 110
terminals and the power line. I would connect white to the terminal
(neutral) and black to the terminal connected to the top of the transformer
The slider is connected to a third terminal; the output is connected to this
terminal and the bottom terminal on the transformer (should be on the
counter clockwise end).
To test, connect a 110 V light bulb and turn the dial fully counter
clockwise. Apply power; if the bulb is bright and dims as you rotate the
dial clockwise change the bottom terminal to the other end. Retest.
If the fuse blows when you rotate, or when you first connect it up, you may
have the slider and one of the end terminals connected to power.
I don't know what the other 4 terminals are for; one may be for safety
ground - it will be connected to the frame of the Variac and should be
connected to the green wire in your power cord.
Good luck,
Bob
"Tim Moran" <Tim-...@neo.rr.com> wrote in message
news:3DD640BC...@neo.rr.com...
: Greetings all,
KTØT
As Larry just pointed out, DO NOT use a Variac by itself to power a
resistance soldering unit!!!! A transformer (like a battery charger) MUST be
used to isolate you from dangerous voltage.
"KTØT" <kt...@mn.rr.com> wrote in message
news:RfvB9.49819$uw6.6...@twister.rdc-kc.rr.com...
: Hi Tim,
:
:
Dick Ganderton
reasons - 6V is too high and 9A is far, far too low.
Rob Paisley
have a schematic.
http://www.variac.com/staco_variable_transformer_100_.htm
Rob.
Tim Moran <Tim-...@neo.rr.com> wrote in message news:<3DD640BC...@neo.rr.com>...
JCunington
>Whilst I don't want to give away "commercial secrets" - for obvious
>reasons - 6V is too high and 9A is far, far too low.
>
I got by with 12 volts at 5 amps, but barely. The xfmr has a circuit breaker on
the secondary, and it cuts out continually, sometimes before I get a good joint
completed. I'm going with the idea of rewinding a microwave transformer with 8
gauge wire. Just got to find a dead one now. The 12 volts doesn't really matter
much, but it does tend to spark if I get the contacts slightly off. 3 volts or
less would cut that problem drastically.
I thinking the 5 amp xfmr might be good for soldering small detail parts so I
don't have them go up in smoke. But for general soldering, I'm going to need
more oomph.
Jay
Jim Marlin
> >
> >Whilst I don't want to give away "commercial secrets" - for obvious
> >reasons - 6V is too high and 9A is far, far too low.
I have a Lionel transformer that is marked
output: open circuit 17 VAC
20 VA max. output.
There are two output connectors.
Can this be used or modified to be used in a resistance unit, and can
anyone tell me how. It is a sealed unit, but it only cost $10. I dont mind
breaking the case.
Thanks in advance.
Jim Marlin
Trainman
Jim Marlin <ab...@charter.net> wrote in message
news:utf2be1...@corp.supernews.com...
17VAC at 20VA is only a little over an amp. You need something like a
magnitude of that. (For example, the numbers in the first quoted post
equals 54VA, the original unit Jay built {which I've seen work} is rated at
60VA, but probably does twice that for a few seconds.)
Dick Ganderton
minimum and you need low voltage, very, very high current.
JCunington
>60VA, but probably does twice that for a few seconds.)
To define "work" here, I managed to solder two .010 pieces of brass together.
The rig fell down on the job when I was trying to build a turnout. The breaker
would cut out before I had the rail soldered down more often than not.
So once again, my 60 watts (nominal) is probably sufficient for small detail
parts, but not for general soldering such as rail to PC ties.
Now if I were to disassemble the xfmr and rewind it for 3 volts at 20 amps, it
might work better, but I'd have to find a new breaker for the secondary. Better
to just rewind a microwave xfmr for 200-350 amps at 3 volts (depending on 600
or 1000 watt capacity). Anything a rail-to-tie circuit could soak up at that
point would be far short of what the xfmr could provide. It probably couldn't
soak up much more than 20 to 30 amps. A filament xfmr would be ideal, but the
largest I've seen at a cheap price so far is only 3 amps @ 3V.
Don't throw out those old tube-TV sets!
Jay
Jim Marlin
How about a single output transformer 120 v input
output of 5vdc 2.4 amp?
Just got a catalog from a co. I never heaard of before called All
Electronics Corp.
Jim Marlin
Gerry Leone
UPDATE: I built the sucker today and it works great. Given that I had an
old battery charger and old soldering pencil, the whole thing cost me only
$20 -- I had to buy a full box of 50 carbon arc gouging rods for $17.
Otherwise it would have cost just $3 (for the 15A footswitch).
There are 4 settings on my battery charger: 12v/8amp, 12v/4amp, 6v/8amp and
6v/4amp. The settings that seem to work the fastest for soldering are the
12v ones. The 6v/8a takes about 10 seconds to heat up the piece.
Bottom line: thanks to Jay Cunington for bringing up the subject and giving
me the confidence that this COULD be done, and to Sven for posting the link
to the article I ultimately used.
-Gerry Leone
http://home.earthlink.net/~gerryleone/trains.htm
"Dick Ganderton" <di...@NoSpamgraskop.demon.co.uk> wrote in message
news:3DD6CF...@NoSpamgraskop.demon.co.uk...
Gerry Leone
"battery charger" route. I saw several new ones on the shelf for $30.
Now... could someone explain this "VA" thing to me? While looking at
transformers I saw a lot of that, and didn't understand it. Thankfully my
fear saved me some money.
KTØT
VA = Volt Amperes... essentially Watts (Volts times Amps)
Bob
"Gerry Leone" <gerry...@earthlink.net> wrote in message
news:Cg%B9.4314$%32.4...@newsread1.prod.itd.earthlink.net...
: Rather than rewinding a microwave transformer, I heartily recommend the
:
:
Jim Guthrie
<gerry...@earthlink.net> wrote:
Gerry,
>I hate to prove you wrong, Dick...
>
>UPDATE: I built the sucker today and it works great. Given that I had an
>old battery charger and old soldering pencil, the whole thing cost me only
>$20 -- I had to buy a full box of 50 carbon arc gouging rods for $17.
>Otherwise it would have cost just $3 (for the 15A footswitch).
>
>There are 4 settings on my battery charger: 12v/8amp, 12v/4amp, 6v/8amp and
>6v/4amp. The settings that seem to work the fastest for soldering are the
>12v ones. The 6v/8a takes about 10 seconds to heat up the piece.
>
>Bottom line: thanks to Jay Cunington for bringing up the subject and giving
>me the confidence that this COULD be done, and to Sven for posting the link
>to the article I ultimately used.
All Dick's message is suggesting is that Jay is pretty lucky in
getting away with it with his particular brand of battery charger.
When you do resistance soldering, the resistive load across the
transformer output is close to zero ohms, which means that voltage
drops and current rises.
In any good apparatus with a transformer in it, the output should cut
out with this increase in current goes above the transformer ratings.
In fact Jay himself stated that the 12v 5a output from his charger cut
out too soon to be any use except possibly for light work. So Jay
himself has admitted that his setup isn't perfect, and the cutout
setting on his 12v 10a output is probably just about enough to allow
him to get a joint done.
But he is overloading his secondary winding on the transformer by
requiring too much current for the winding and that may have medium to
long term consequences on the health of his equipment. A proper
transformer for resistance soldering should be designed for high
current output if reliability is to be ensured. And if you haven't
modified the charger to get the AC output direct from the transformer
secondary, then there is a diode somewhere in the circuit that is
being driven over its limits as well.
So there should be a caveat on using battery chargers for resistance
soldering. Jay is getting away with it, others might not.
Jim.
JP
> A 20VA transformer is far too small. You need to be looking at 100VA
> minimum and you need low voltage, very, very high current.
>
What about using the guts from a 100/140W soldering gun?
JP
JCunington
>So there should be a caveat on using battery chargers for resistance
>soldering. Jay is getting away with it, others might not.
>
Something got lost in the translation. My rig is not a battery charger. It's a
simple transformer with a circuit breaker on the secondary, built-in. I'm using
AC, not DC.
Yes, I'm probably overloading the secondary, which is why I'm planning on using
the microwave rewinding idea. A 600-watt transformer (5A @ 120V) should be able
to produce about 200A at 3V. I emailed the guy that put up the link I quoted
some messages back from Dr. Spiff (drspiff). He said he was able to melt a 1/4"
copper rod "just seeing what it could do." So model railroading uses would
never come close to taxing that transformer.
Jay
JCunington
>What about using the guts from a 100/140W soldering gun?
>
I could be wrong, not being an electrical expert, but I think those are wired
to produce heat, not current. How, I'm not sure. Can somebody explain how those
things work?
Jay
JCunington
>How about a single output transformer 120 v input
>output of 5vdc 2.4 amp?
>Just got a catalog from a co. I never heaard of before called All
>Electronics Corp.
>
I'm pushing 60 watts (12V times 5 amps) and barely cutting it. Your transformer
will barely produce 12 watts. Not enough amps. You've got to push amps. High
amps, low voltage. The amps produce the heat, not the volts.
One article I read the guy said he was making do with 6.7 amps at 6 volts,
another said 20 amps at 3 volts. My feeling is that if you're not pushing at
least 10-15 amps, you're going nowhere fast. That's just extrapolation based on
my results at 5 amps and what other people have said. Twenty amps is probably
closer to the minimum in my uninformed guesstimation.
At any rate, you can do it without burning the house down.
Jay
Daniel A. Mitchell
soldering tip, like any other elctrical-resistance heater. Power (heat)
= current squared X resistance. Since the tip is inherently low
resistance, a lot of current is needed to get it really hot.
The current comes from a simple transformer in the body of the solder
gun ... usually with just a couple 'turns' of heavy wire for the
secondary ... low voltage, high current.
The idea of using this transformer for a resistance unit has some merit,
but I'd go a lot heavier than the 140 watt solder guns ... these are
likely rated for only very intermittent use ... more so than a typical
resistance unit. I've seen 300 watt solder guns ... these would seem
more likely starting points. Unfortunately, such a gun costs a major
fraction of what a small resistance unit cost. Now, if you could get a
junk one CHEAP ...
I know my 150 watt resistance unit has a transformer with perhaps three
times the mass of a 150 watt solder gun.
Dan Mitchell
==========
Daniel A. Mitchell
Power (heat) = current X voltage = current squared X resistance =
voltage squared / resistance.
You need *BOTH* current and voltage to get power.
High current at NO voltage = NO power.
High voltage with NO current = NO power.
In this application it's a lot better (easier and safer) to get that
power from high current. However, you still need SOME voltage.
Dan Mitchell
==========
Lawrence Costa
>>
>>What about using the guts from a 100/140W soldering gun?
It might work if you remove the heavy sheet winding that feeds the tip
and wind with some #12 or so, perhaps about ten turns. The existing
winding probably produces about 1V open circuit. However the gun is
made for short duty cycles. I guess this wil do for resistance
soldering. I suspect the people interested would like to hear how many
turns of wire you put on.
Fred Dabney
Actually, yes.
They are wired to produce a lot of current at a very low voltage,
but that current is passed through a heavy copper wire with
the tip forged into the middle.
The current, passing through the wire heats the copper
which is what makes it work.
One of those might indeed be a good source for the
transformer part of the resistance rig. You'd still need
to fabricate the workpiece, provide a better switch such
as a foot switch etc. And very heavy wire between the
xformer and the workpiece. You don't want it to get
as hot as the area you're working on...
Fred D.
Fred Dabney
All
> >Electronics Corp.
"All" has been around a long time. I don't know what they
do now but they used to be a dealer in surplus industrial
electronic parts and stuff, packaged for the electronics
experimenter.
There are a bunch of such places. One of my favorites
was Harbach and Rademan for really neat stuff.
Fred D.
Dick Ganderton
the job then you are simply not passing enough current through the
joint. A good RSU will only take around 1 second to get the joint up to
soldering temperature.
To give you an indication of the sort of current you need I measured one
of my RSUs at 70A.
Dick Ganderton
soldering iron. They work on totally different principles.
The RSU produces its heat by passing a very high current through the
joint. The heat produced is very localised and can be very high,
depending on the current.
A conventional soldering iron utilises a hot copper bit and relies on
conduction to transfer the heat in the bit to the work. As this heat
transfer takes time and the material being soldered conducts the heat
away from the joint, the speed with which the joint reaches soldering
temperature can be quite long. If the bit doesn't have enough heat
reserve the joint may never get to soldering temperature, or, when it
finally does so does quite a lot of the model and other bits already
soldered on fall off.
Solder guns generate their heat by passing curent through the bit
itself, rather than through a heating element. In my opinion they are a
waste of time. No heat reservoir in the bit, unwieldy and awkward to
use.
A good RSU would make mincemeat of two bits of 0.010" pieces of brass. I
can solder 3/8" AF brass hex bar onto a piece of brass 1/8" thick x 1"
wide x 18" long with my RSU.
Why do you need a breaker in the secondary circuit? A fuse in the
primary circuit is all you need. Also you need to switch the primary
with a foot switch.
Charles Linsley
Jim Guthrie <j...@sprockets.co.uk> wrote:
[snip]
>But he is overloading his secondary winding on the transformer by
>requiring too much current for the winding and that may have medium to
>long term consequences on the health of his equipment. A proper
>transformer for resistance soldering should be designed for high
>current output if reliability is to be ensured. And if you haven't
>modified the charger to get the AC output direct from the transformer
>secondary, then there is a diode somewhere in the circuit that is
>being driven over its limits as well.
>
>So there should be a caveat on using battery chargers for resistance
>soldering. Jay is getting away with it, others might not.
I have a battery charger that I have been toying with the idea of
using for a resistance soldering unit, if I can do so without spoiling
its use for charging batteries. I might anyway, as I rarely have a
need to charge my car battery.
It would seem to be ideally suited for the job (well, as ideally suited
as a 12V device can be, anyway). As I recall, it has three settings --
a low-current "trickle" charge (I don't remember exactly what the
current rating is) rated for continuous duty, a 10A normal charge
good for 12 hours, or so (that's how long the built-in timer runs),
and -- here's the good one -- a 50A "jumper" setting rated for a very
light duty cycle - 10 sec on, 1 min off, or something like that.
If I can figure out how to make the connection to the electrode/workpiece
without ruining the connection to the battery terminal clamps, and if the
2-3 sec dead short across the output doesn't burn anything out, I'll be
all set.
--
Chuck Linsley
lin...@linsley.best.vwh.net
KTØT
I suggested to Gerry Leone that he make an "Interface Board" to accomplish
your need. Sounds like it worked... Anyway,
Take a board or other insulator and put a couple of bolts through it,
insulating the heads where they might short against something. The bolts
should be large enough for your battery clamps to get a good grip on them.
Then, fasten your RSU leads to those bolts. Now, you can use the charger for
either purpose.
--
73 de KTØT
Bob Schwartz
Modeling Waseca, MN in the 50s
"Charles Linsley" <lin...@linsley.best.vwh.net> wrote in message
news:yzgC9.290$I1.2...@iad-read.news.verio.net...
:<SNIP>
: If I can figure out how to make the connection to the electrode/workpiece
:
Charles Linsley
KTØT <kt...@mn.rr.com> wrote:
>Chuck,
>I suggested to Gerry Leone that he make an "Interface Board" to accomplish
>your need. Sounds like it worked... Anyway,
>
>Take a board or other insulator and put a couple of bolts through it,
>insulating the heads where they might short against something. The bolts
>should be large enough for your battery clamps to get a good grip on them.
>Then, fasten your RSU leads to those bolts. Now, you can use the charger for
>either purpose.
Yeah, I read that article. That's what I'll probably do, at least to
try it out. Actually, I'll probably screw several nuts onto the bolt,
and clamp to the nuts to get a larger clamping area. Hmm, reduce the
clamp-to-nut resistance vs. adding the nut-to-bolt resistance... maybe
a toss-up. I remember my dad had something with Cu bolts/nuts, but I
can't remember what it was. Maybe it was the spot welding unit that he
made from a big, old transformer; that thing must have weighed 10 or
15kg.
--
Chuck Linsley
73 de N6GAL
lin...@linsley.best.vwh.net
TOM
> You cannot equate a Resistance Soldering Unit to a conventional
> soldering iron. They work on totally different principles.
>
> The RSU produces its heat by passing a very high current through the
> joint. The heat produced is very localised and can be very high,
> depending on the current.
>
> A conventional soldering iron utilises a hot copper bit and relies on
> conduction to transfer the heat in the bit to the work. As this heat
> transfer takes time and the material being soldered conducts the heat
> away from the joint, the speed with which the joint reaches soldering
> temperature can be quite long. If the bit doesn't have enough heat
> reserve the joint may never get to soldering temperature, or, when it
> finally does so does quite a lot of the model and other bits already
> soldered on fall off.
>
> Solder guns generate their heat by passing curent through the bit
> itself, rather than through a heating element. In my opinion they are a
> waste of time. No heat reservoir in the bit, unwieldy and awkward to
> use.
>
> A good RSU would make mincemeat of two bits of 0.010" pieces of brass. I
> can solder 3/8" AF brass hex bar onto a piece of brass 1/8" thick x 1"
> wide x 18" long with my RSU.
>
> Why do you need a breaker in the secondary circuit? A fuse in the
> primary circuit is all you need. Also you need to switch the primary
> with a foot switch.
Informative post, thanks...
Most large (75 watt and larger) soldering guns (Weller comes to mind) do,
indeed, pass the voltage through the tip to produce the heat, and they are
quite inefficient, since the tip area is relatevely small. They are made for
soldering such things as wire, stained glass windows, etc., not large flat
surfaces. For that, use an RSU, there is no substitute for the ease and
speed. But you do have to be careful as it's quite easy to "blow" holes in
the pieces you're soldering. The best idea is practice, practice,
practice... :>))
Having said that, the majority of soldering irons have heating elements. The
resistance wire in the element produces the heat which is conducted to the
tip (bit).
http://www.coopertools.com/brands/weller/
<><><> TOM <><><>
-------------------------
JCunington
>A good RSU would make mincemeat of two bits of 0.010" pieces of brass. I
>can solder 3/8" AF brass hex bar onto a piece of brass 1/8" thick x 1"
>wide x 18" long with my RSU.
"My RSU is bigger than your RSU." This isn't about brute force, it's about
finesse. I should think a good RSU would have a power control so it _wouldn't_
make mincemeat of .010" brass. If the unit cooks brass that thin, it's of no
use to me.
>Why do you need a breaker in the secondary circuit? A fuse in the
>primary circuit is all you need. Also you need to switch the primary
>with a foot switch.
The xfmr I purchased has the breaker built into the xfmr. I kept blowing 1 amp
fuses on the primary, so I took out the primary fuse and let the secondary's
breaker handle it. Since the transformer was 60 watts nominal, I figured I
should pull 3/4 amp max at 120 volts. I didn't sit down and calculate 120 volts
RMS, but it works out something around 80-90 volts, IIRC. If I'm blowing a 1
amp fuse, I'm pulling something above 90 watts, or 7-8 amps through a 12V 5 amp
transformer before the breaker trips.
Got a foot switch. Works great.
Jay
Fred Dabney
bit
> itself, rather than through a heating element. In my opinion
they are a
> waste of time. No heat reservoir in the bit, unwieldy and
awkward to
> use.
They have another drawback. If you use it on sensitive
electronics, you might not have any when you're finished.
Older guns can have a small leakage between the tip
and the power line- not enough to make a shock hazard
but enough to blow chips.
More subtle is inductive coupling between the field around
the gun and any closed loops on a circuit board. Current
flow can be induced in the same way any transformer
works, and this too can blow parts.
I suspect the person who was worried about magnetic
fields due to an impending pace maker implant will
want to get rid of his if he has one...
Fred D.
Gerry Leone
> your need. Sounds like it worked... Anyway,
>
> Take a board or other insulator and put a couple of bolts through it,
> insulating the heads where they might short against something. The bolts
> should be large enough for your battery clamps to get a good grip on them.
> Then, fasten your RSU leads to those bolts. Now, you can use the charger
for
> either purpose.
And this is exactly what Gerry Leone did! And indeed it did work.
Gerry Leone
> You haven't proved me wrong! If it takes your RSU 10 seconds to heat up
> the job then you are simply not passing enough current through the
Actually what I'd said was that on the second-lowest setting it takes 10
seconds to heat the piece. The highest setting (12v/8a) will turn the tips
of the carbon rod red after about a second.
Regardless, there's no "right and wrong" -- the thing, in my case, works.
It may not for others.
KTØT
Bob
"Gerry Leone" <gerry...@earthlink.net> wrote in message
news:UrkC9.6082$%32.5...@newsread1.prod.itd.earthlink.net...
: > I suggested to Gerry Leone that he make an "Interface Board" to
:
:
Steve Caple
> And this is exactly what Gerry Leone did! And indeed it did work.
Going to put some pictures up?
--
Steve
Big Fork & Diehl RR
* Steam opens the envelope for me *
Jim Guthrie
Jay,
>Something got lost in the translation. My rig is not a battery charger. It's a
>simple transformer with a circuit breaker on the secondary, built-in. I'm using
>AC, not DC.
Sorry - got your setup mixed up with all the talk about using battery
chargers :-)
Jim.
Dick Ganderton
complete the job in a very short time, not blow it apart.
Of course a good RSU will have a variety of power settings - there are
times when you need the brute force of the maximum power setting. There
are also times when you need the finesse of the lowest power setting.
I wouldn't want to operate without a fuse in the primary circuit of an
RSU.
Bob May
transformer, not the 80-90V that you calculated!
Please learn what you are dealing with.
FWIW, I often use my RSU for doing bronze soldering of old broken statues so
my RSU is bigger than yours!
--
Bob May
Global WARMING???
What I want to know is when I can start growing wheat in Greenland again!
JCunington
>Sorry - got your setup mixed up with all the talk about using battery
>chargers :-)
'Sokay.
Jay
JCunington
>transformer, not the 80-90V that you calculated!
OK, well in that case at 60W I should be pulling 1/2 amp and not blowing the
hell out of 1 amp fuses at 12 volts.
>Please learn what you are dealing with.
DC I know. AC is a strange animal. I can wire wall sockets and light fixtures,
but not much else to do with AC.
>, I often use my RSU for doing bronze soldering of old broken statues so
>my RSU is bigger than yours!
>
Cool. I had no idea such a thing existed.
Jay
JCunington
>I suspect the person who was worried about magnetic
>fields due to an impending pace maker implant will
>want to get rid of his if he has one...
>
...And then we can find out if you CAN turn a soldering gun into an RSU...
Jay
Fred Dabney
statues so
> >my RSU is bigger than yours!
> >
>
> Cool. I had no idea such a thing existed.
Years ago, there was a firm named "Brookstone". They
were a mail order tool supplier, and had a lot of neat
things for the craftsman and modeler.
They used to sell an RSU that was a beast. It had
an adjustable transformer- the secondary was wrapped
around an iron rod, and a front panel knob moved
a tap along the secondary. Rather like a strange
looking variac with an isolated secondary.
It was intended for jewelry work, repairing and resizing
rings, that sort of thing.
I never put a meter on it. but at lowest level it wouldn't
get a pencil lead warm, and at high "heat" I was able
to melt through a 1/4" piece of brazing rod as fast as
I could move the workpiece.
I need to get a pair of tweezers for it, but at present I
use a handle I made of a small modular soldering
iron to hold the graphite rod.
Very handy device...
Fred D.
Bob May
you just have to know how many you are demanding from the line! Just
because the transformer is a 60W transformer, doesn't mean that it will only
take and use 60W off of the line. It can actually take a lot more current
if so directed to. Remember that the transformer just converts the power
from one Voltage/Current to another and the limit of the current that it
will draw is the resistance of the winding connected to the wall. Since
that resistance is probably on the order of 3 ohms or so, that means that
you can probably get 40amps RMS through that winding if you really tried.
THAT, Sir, is a lot more than a half of an amp! Actual current will be less
as the secondary current will also be limited by the internal and external
resistances of the secondary circuit but it will be easy to get a resistance
low enough to exceed 60W of dissapation without trouble!
Scott G. Perry
What would bbe the perfect type of transformer to use then? What volt/volt amp
if you were just going to go to Radio Shack and get the unit?
Scott Perry
Traintools Egroup
KTØT
think you can find a suitable transformer at the Shack but you can get by
with an old car battery charger. Others suggest a lower output voltage.
Have you looked at http://www.trainweb.org/girr/tips/tips1/solderer.pdf ?
Looks good to me.
--
73 de KTØT
Bob Schwartz
Modeling Waseca, MN in the 50s
"Scott G. Perry" <scott...@hotmail.com> wrote in message
news:3DDC2573...@hotmail.com...
: Got confused...help me out.
:
JCunington
>What would bbe the perfect type of transformer to use then? What volt/volt
>amp
>if you were just going to go to Radio Shack and get the unit?
>
Radio Shack's ain't got enough beef to 'em. Articles I've read say you want an
old tube filament transformer. They run around 3 volts and the larger ones can
put out 20 amps or more. A father in my daughter's violin class builds tube
guitar amps, so they can still be had, but it's a specialty now. You're not
likely to find one laying around unless Great-aunt Martha finally throws out
the B&W set.
Everything I've read says 6 volts or less, ideally 3 or under, 20 amps or
better. The more amps you push, the thicker the metal your can work with (I
think). At higher voltages sparking becomes a problem.
One web page the guy said he's getting by with 6.7A at 6 volts. Another guy
turned his own transformer by stripping a microwave xfmr secondary and
replacing it with 8 gauge wire. That's 600 watts, some serious power.
I've got a 12V 5A transformer. It works OK, but it has a built-in circuit
breaker that keeps tripping on me, but it's unpredictable. Sometimes I get a
joint done, sometimes not. If I had my druthers I'd strip the secondary by 3/4
of its turns and run 3V at 20 amps. Of course I'd need a heavier gauge wire and
take out the breaker.
Jay
Gerry Leone
It would underwhelm you, Steve. I got 3 3/8" bolts and mounted them
"threads up" through a piece of plywood. I clamp the battery charger leads
to two of the bolts, clamp the foot switch to one of the charger bolts and
the 3rd bolt, and clamp the probe/alligator clip to the other charger bolt
and footswitch bolt.
Pretty primitive.
Steve Caple
> You're not likely to find one laying around unless Great-aunt Martha
> finally throws out the B&W set.
How about an old tube-type stereo console? We have an old Phillips unit my
wife brought from Germany over 25 years ago that now serves as a credenza
(no tubes available, and wouldn't be worth the effor if there were).
Maybe I'll bash it apart for the solid teak, and see how beefy the filament
transformer looks - or is a suitable f.t. a TV only item?
Håvard Houen
> Everything I've read says 6 volts or less, ideally 3 or under, 20 amps or
> better. The more amps you push, the thicker the metal your can work with (I
> think). At higher voltages sparking becomes a problem.
>
> One web page the guy said he's getting by with 6.7A at 6 volts. Another guy
> turned his own transformer by stripping a microwave xfmr secondary and
> replacing it with 8 gauge wire. That's 600 watts, some serious power.
>
> I've got a 12V 5A transformer. It works OK, but it has a built-in circuit
> breaker that keeps tripping on me, but it's unpredictable. Sometimes I get a
> joint done, sometimes not. If I had my druthers I'd strip the secondary by 3/4
> of its turns and run 3V at 20 amps. Of course I'd need a heavier gauge wire and
> take out the breaker.
>
> Jay
I have an English unit with 5 different output voltages (1, 1-1/2, 2, 3,
& 4-1/2) and the ability to deliver current of up to 50 amps.
I am extremly pleased with my unit, I doubt very hard that som battery
charger could provide the same satisfaction.
At £ 125,- it is quite expensive, but to me it is worth every penny.
European modellers should consider it, check it out at
http://www.fourtrack.co.uk/acatalog/
I am in no way associated with the company, I am just a very happy customer.
Regards, Håvard H.
KTØT
high-voltage windings. If you see more than four or five wires coming out of
the transformer, it's probably a multi-purpose one. Still might have enough
oomph to do some soldering, just make sure you use the low voltage outputs.
--
73 de KTØT
Bob Schwartz
Modeling Waseca, MN in the 50s
"Steve Caple" <steve...@spamworldnet.att.spamnet> wrote in message
news:MPG.18464d2d1...@netnews.worldnet.att.net...
JCunington
>I have an English unit with 5 different output voltages (1, 1-1/2, 2, 3,
>& 4-1/2) and the ability to deliver current of up to 50 amps.
Now that's a nice rig. Plenty of power.
Another source I read about was dental supply houses. RSUs are used for some
dental work apparently. One guy I heard about got a used professional rig for
$40 US. Your results may vary.
Jay
Bob May
20amps from one of the electronics surplus places. Outputs are usually in
the 8V range and often are double output windings which can be seperated and
used in parallel rather than series.
Remember that if you buy 2 transformers at the same time (the same
transformer type and source, of course) you can parallel them without
problems. For little stuff, one transformer will be quite sufficient but
for heavier stuff, you may want to have more.
Dick Ganderton
the "Graskop" Resistance Soldering Unit. This has six output powers, a
low voltage foot switch (for safety) and a pair of very flexible leads
one of which has a collet for holding 4mm dia. carbon tips. It sells for
90 GBP delivered to a UK address. It is also has full CE approval. I
have supplied several to modellers outside the UK, including Sweden. I
have measured 70A on full power.
I wind my own special transformer for this unit as there is nothing
available ready wound that is suitable for an RSU.
Håvard Houen wrote:
>
snip
Ray Haddad
and "Bob May" <bob...@nethere.com> instead replied:
>Remember that if you buy 2 transformers at the same time (the same
>transformer type and source, of course) you can parallel them without
>problems. For little stuff, one transformer will be quite sufficient but
>for heavier stuff, you may want to have more.
Be sure not to cross phase the outputs or you'll have those "problems"
you said would not occur. Cross phased AC outputs present a maximum
load to a transformer.
Best,
Ray
Rick Jones
> A father in my daughter's violin class builds tube
> guitar amps, so they can still be had, but it's a specialty now. You're not
> likely to find one laying around unless Great-aunt Martha finally throws out
> the B&W set.
Some audiophiles swear that tube amps are superior to transistor
amps. You had to figure that eventually a computer motherboard maker was
going to come up with something just for them:
http://www.digit-life.com/articles2/aopentube/
--
Rick Jones
Remove the Extra Dot to e-mail me
Last summer I joined the Sexual Freedom League, and within two
months my team was in 1st Place.
Steve Martinak
> I have completed my own resistance soldering unit as of yesterday, Nov. 9.
> Given my luck with electrical stuff when I don't know what the heck I'm doing,
> the darn thing actually works!
>
> I used a 12V 5A transformer as the base for it (American Science & Surplus,
> $10; they also have a 12V 10A xformer). Also from AS&S, 1/4" graphite rod ($1)
> and a foot switch ($1.50). From Radio Shack, banana plugs (male and female),a
> fuse holder, and 1A fuses. You'll need some brass bar stock (K&S, about $1.69),
> two 3/8"-7/8" automotive hose clamps ($2), two brass gas line couplings ($.75
> each), and some 16 ga. line cord. Also some 3/4" dowel for insulators on the
> handles.
>
> The basic wiring is this: On the transformer primary, attach one wire from the
> wall socket to the transformer. The other wire goes to the fuse holder. The
> second wire on the fuse holder will go to the foot switch. The return wire
> from the foot switch goes to the transformer primary. The secondaries get
> hooked to electrical sockets for the banana plugs.
>
> I made a tweezer type attachment for expediency. Cut off about 6 inches of bar
> stock. Find the midpoint and bend it into a lazy U-shape. Take the dowel. Cut
> off two sections about 4 inches long. Drill a hole lengthwise down the middle
> of the dowels of sufficient diameter to feet the wire through. Drill a hole at
> one end for the brass gas line couplings to fit in. Drill your gas line
> couplings out to a sufficient diameter to hold your graphite rod (mine was
> 1/4"; 1/8" arc-welding electrode works also). Feed the handle wires through the
> dowels. Solder the ends to the couplings, then epoxy the couplings into the
> handles. On my handles the graphite rod is a press fit, so no retainer screws
> are needed. At the other end of the handle wires, solder the male banana plugs
> on.
>
> That's all there is to it. I found I can solder two pieces together with about
> 3 seconds of current. It works like a charm. Not bad for $25.
>
> Now before anyone who has the multi-hundred dollar commercial units starts with
> the "You have to have less than 6 volts." routine, mine works fine. I'm
> satisfied with it. It works. You can do it yourself. There are web sites out
> there (don't ask me, I didn't save them on my browser) to show you how with
> more explanation than I've provided here.
>
> Now to build some turnouts...
I've read this entire thread with a great deal of interest since I'm considering
an RSU, but I just can't seem to justify the purchase prices they're commanding.
However, what I *haven't* noticed is anyone using one of those relatively low-cost,
house-current arc welding sets as the power source. Not even a mention that you
*can't* use them for whatever reason. Anyone in the know have any relevant
comments or experience?
Steve
Jim Marlin
"Steve Martinak" <"mart832 -a"@t- ameritech.net> wrote in message
news:YkBF9.3834$Kw6.2...@newssrv26.news.prodigy.com...
Just got a battery charger. 120 v in. output is 2/10 amps continuous, 50
amp intermittent 10 sec. max on. 180 max sec off. which setting should I
use?
Thanks.
Jim Marlin
ala...@iinet.net.au
ameritech.net> wrote:
> I've read this entire thread with a great deal of interest since I'm considering
>an RSU, but I just can't seem to justify the purchase prices they're commanding.
>However, what I *haven't* noticed is anyone using one of those relatively low-cost,
>house-current arc welding sets as the power source. Not even a mention that you
>*can't* use them for whatever reason. Anyone in the know have any relevant
>comments or experience?
>
>Steve
>
I am seriously thinking of making some extension tips for my
portable spot welder for a RSU but at 1.5 kW output I think it may be
a bit of an overkill! It has made a beaut job of frames for my HO
& Sn3.5 layout and the club's N scale modules using 75 x 30 mm steel
stud. Very light and rigid and quick to make.
Alan
in beautiful Golden Bay, Western Oz, South 32.25.42, East 115.45.44
VK6 YAB ICQ 6581610
KTØT
Hope y'all had a great holiday. I mentioned that I had found a variac at
Dexus - well I think I misspelled it. Here's their web site with address.
They don't list a variac; probably below their price threshold for listing.
Mine cost
$30 several years ago. You just have to go in and meander around - kinda
fun.
BTW, your web site is popular; Earthlink says you have used your allotment
for the month.
Bob
"Gerry Leone" <gerry...@earthlink.net> wrote in message
news:UrkC9.6082$%32.5...@newsread1.prod.itd.earthlink.net...
: > I suggested to Gerry Leone that he make an "Interface Board" to
accomplish
: > your need. Sounds like it worked... Anyway,
: >
: > Take a board or other insulator and put a couple of bolts through it,
: > insulating the heads where they might short against something. The bolts
: > should be large enough for your battery clamps to get a good grip on
them.
: > Then, fasten your RSU leads to those bolts. Now, you can use the charger
: for
: > either purpose.
:
: And this is exactly what Gerry Leone did! And indeed it did work.
:
:
: --
: -Gerry Leone
: http://home.earthlink.net/~gerryleone/trains.htm
:
: