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Anti-soldering flux?

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bob prohaska

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Oct 13, 2017, 9:46:26 PM10/13/17
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I just broke a drawer pull on a family heirloom desk. The pull
consists of a cast brass base with a tab sticking out. The tab
is bent down through the ring, holding it flexibly captive. The
tab is about 1/8" wide and half that thick, the ring about 2"
diameter and 1/8" thick at the tab.

The tab broke where it was bent, so the easiest way to line
up the break is to put the ring back where it belongs and
solder the broken tab back in place. If the tab is soldered
with the ring out, then some bending will be needed to put
the ring back. That seems a good way to break the tab again.

If I can find something to coat the ring pull, so the solder
won't wet it, I think there's a decent chance of success. I
don't think lead-tin solder will be strong enough and I can't
think of a reliable anti-wetting coating that will stand up
to silver soldering temperatures. Aluminum foil comes to mind,
and might work for soft solder but I don't think it'd take
the heat needed for silver soldering.


Thanks for reading, and any ideas.

bob prohaska



Bill

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Oct 13, 2017, 10:50:42 PM10/13/17
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30 years ago, soldering gold with gold solder, I would wet an artist's
brush with chloroform and pick up the rouge off a stick with an artist's
brush - then paint the mix on the work. Apply our flux, then heat with
torch or oven to soldering temp.

Placement of the antiflux was very controllable. If the antiflux got
somewhere we didn't want it - it wiped off smooth surfaces easily.
After soldering it was kinda baked on, and would require a bit more
effort.

I think you could use any fast drying liquid that does not leave any
residue that might react with your flux. etc.

Might, or might not, work for what you're doing. Definitely run some
trials before you attempt the real thing.

--
Email address is a Spam trap.

Bill

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Oct 13, 2017, 10:52:02 PM10/13/17
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Rouge == red jewelers rouge, the stuff that's used on buffing wheels to
polish metal.

cl...@snyder.on.ca

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Oct 13, 2017, 11:09:21 PM10/13/17
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Test with "liquid paper" - it is used to keep damascus from sticking
to the shell in forging.

Gerry

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Oct 13, 2017, 11:26:17 PM10/13/17
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I have used that when silver brazing - works for me.

whit3rd

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Oct 14, 2017, 12:47:12 AM10/14/17
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On Friday, October 13, 2017 at 6:46:26 PM UTC-7, bob prohaska wrote:
> I just broke a drawer pull...
> If I can find something to coat the ring pull, so the solder
> won't wet it, I think there's a decent chance of success.

There's a commercial product, Tix Anti-Flux, that should work.

Me, I just stay sloppy, and buff the excess off afterward.

dca...@krl.org

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Oct 14, 2017, 11:16:38 AM10/14/17
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On Friday, October 13, 2017 at 9:46:26 PM UTC-4, bob prohaska wrote:
>
>
> If I can find something to coat the ring pull, so the solder
> won't wet it, I think there's a decent chance of success. I
> don't think lead-tin solder will be strong enough and I can't
> think of a reliable anti-wetting coating that will stand up
> to silver soldering temperatures. .
>
>
> Thanks for reading, and any ideas.
>
> bob prohaska

Real silver solder takes a lot of heat. I would try the solder which is about 5% silver and the rest tin before I went to high temp solder ( really silver brazing )

Dan

bob prohaska

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Oct 14, 2017, 12:53:42 PM10/14/17
to
whit3rd <whi...@gmail.com> wrote:
> On Friday, October 13, 2017 at 6:46:26 PM UTC-7, bob prohaska wrote:
>> I just broke a drawer pull...
>> If I can find something to coat the ring pull, so the solder
>> won't wet it, I think there's a decent chance of success.
>
> There's a commercial product, Tix Anti-Flux, that should work.
That in concept is exactly what I'm looking for. Trouble is, they
say it's best with SO250 solder, which appears to be low melting
point and has no strength or other specification. Since the original
brass broke, I think silver braze will be necessary but I'll email
them and learn what I can.

> Me, I just stay sloppy, and buff the excess off afterward.

Can't do that in my predicament; if the solder flows between
ring pull and plate there's no way to get it out.

Thanks very much for posting!

bob prohaska

Bob La Londe

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Oct 14, 2017, 2:48:54 PM10/14/17
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"Bill" wrote in message
news:beWdnVNUsKXm5nzE...@giganews.com...

On Sat, 14 Oct 2017 01:46:24 -0000 (UTC), bob prohaska wrote:

> I just broke a drawer pull on a family heirloom desk. The pull
> consists of a cast brass base with a tab sticking out. The tab
> is bent down through the ring, holding it flexibly captive. The
> tab is about 1/8" wide and half that thick, the ring about 2"
> diameter and 1/8" thick at the tab.
>
> The tab broke where it was bent, so the easiest way to line
> up the break is to put the ring back where it belongs and
> solder the broken tab back in place. If the tab is soldered
> with the ring out, then some bending will be needed to put
> the ring back. That seems a good way to break the tab again.
>
> If I can find something to coat the ring pull, so the solder
> won't wet it, I think there's a decent chance of success. I
> don't think lead-tin solder will be strong enough and I can't
> think of a reliable anti-wetting coating that will stand up
> to silver soldering temperatures. Aluminum foil comes to mind,
> and might work for soft solder but I don't think it'd take
> the heat needed for silver soldering.
>
> Thanks for reading, and any ideas.
>
> bob prohaska

How about... White Out? Its used in making canister damscus steel. That's
a lot higher temperature than silver solder. Not sure how you would go
about removing it afterwards though. Another option might be graphite spray
lubricant. I use it all the time in lead casting, although the base metal
(aluminum) of the mold does not wet easily to lead anyway.




Ed Huntress

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Oct 14, 2017, 2:54:46 PM10/14/17
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Hi Bob. This may be a reach, but the anti-fluxes used in silver
brazing dental work are graphite (pencil lead, or plumbago in alcohol)
and whiting (calcium carbide) in water or alcohol.

I have no experience with them, but I encountered them several times,
years ago, when I wrote about brazing.

Good luck!

--
Ed Huntress

et...@whidbey.com

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Oct 14, 2017, 6:15:23 PM10/14/17
to
I hjave used lampblack with good results. The coating is delicate, and
flux might clean it off (though it didn't when I used it), but it is
easy to apply from a smoky candle flame and easy to remove.
Eric

bob prohaska

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Oct 14, 2017, 9:36:57 PM10/14/17
to
It seems as if correction fluid might be a pretty good bet. Near as I
can tell the pigment is titanium dioxide, which is a fairly inert
ceramic. It can be applied thick, perhaps it'll resist flux. Shouldn't
be too hard to set up a rehearsal with some scrap brass for a test.

Speaking of setup, holding the parts in position looks rather difficult;
the broken tab is only about 1/8" square. Can anybody suggest some sort
of putty that will resist brazing heat, hold the (very small) parts in
place and not sinter to something indestructible when heated? Maybe
glazier's putty, but that can get rather hard. Fire stop caulking?
modeling clay? Perhaps something made from household chemicals like
talc and water?

Thanks for everyone's ideas!

bob prohaska



Bob La Londe

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Oct 14, 2017, 10:12:35 PM10/14/17
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"bob prohaska" wrote in message news:orue3n$8bb$1...@dont-email.me...
*****************

Modeling clay maybe?

Bob La Londe

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Oct 14, 2017, 10:43:22 PM10/14/17
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***

I used to use fire stop caulk all the time for construction when penetrating
fire rated walls of communications cable and conduit sleeves. The stuff is
really quite tough when cured. It might be quite hard to remove. I never
did a post mortem on any that had been through a fire though.


whit3rd

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Oct 15, 2017, 1:12:26 AM10/15/17
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On Saturday, October 14, 2017 at 6:36:57 PM UTC-7, bob prohaska wrote:
[about anti-flux]

> It seems as if correction fluid might be a pretty good bet. Near as I
> can tell the pigment is titanium dioxide...

> the broken tab is only about 1/8" square. Can anybody suggest some sort
> of putty that will resist brazing heat, hold the (very small) parts in
> place and not sinter to something indestructible when heated? Maybe
> glazier's putty, but that can get rather hard. Fire stop caulking?
> modeling clay? Perhaps something made from household chemicals like
> talc and water?

Modeling clay (the greasy kind) or putty are no good. Casting sand
and a little molasses is traditional for high heat, though. Or a mineral clay
might work, I know painting a little clay slip onto copper wire keeps hot
glass from sticking.

Bill

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Oct 15, 2017, 1:36:20 AM10/15/17
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On Sun, 15 Oct 2017 01:36:55 -0000 (UTC), bob prohaska wrote:

> It seems as if correction fluid might be a pretty good bet. Near as I
> can tell the pigment is titanium dioxide, which is a fairly inert
> ceramic. It can be applied thick, perhaps it'll resist flux. Shouldn't
> be too hard to set up a rehearsal with some scrap brass for a test.
>
> Speaking of setup, holding the parts in position looks rather difficult;
> the broken tab is only about 1/8" square. Can anybody suggest some sort
> of putty that will resist brazing heat, hold the (very small) parts in
> place and not sinter to something indestructible when heated? Maybe
> glazier's putty, but that can get rather hard. Fire stop caulking?
> modeling clay? Perhaps something made from household chemicals like
> talc and water?
>
> Thanks for everyone's ideas!
>
> bob prohaska

We used a soldering investment - something like this:
https://whipmix.com/products/soldering-investments/

Soldering investment can be used in very creative ways to make an
"index" that would hold your parts in a predermined relationship while
the actual brazing is done.

I'm a bit concerned about the braze (whatever you use) flowing well into
your joint. You might need to be very slective of the solder for it's
flow properties, and/or carefully prepare (open up) the jointa tiny
amount so your filler metal will penetrate the joint fully.

rangerssuck

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Oct 15, 2017, 5:42:15 AM10/15/17
to
On Friday, October 13, 2017 at 9:46:26 PM UTC-4, bob prohaska wrote:
I know you've been getting some good advice here, but I think these questions would be better answered in a jewelry making forum. Jewelers deal with stuff like this all day every day, and surely know "stuff" that we mere metal manglers don't know.

Just sayin'

Pete Keillor

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Oct 15, 2017, 7:04:44 AM10/15/17
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On Sun, 15 Oct 2017 01:36:55 -0000 (UTC), bob prohaska
Do you have a jeweler's torch? You're going to need one. I wrecked a
drawer pull about that size with my smallest torch.

Given my prior experience, I'd have a long look for a suitable
replacement, just in case. There are lots of cabinet hardware outfits
still around. I got my sister some "reed & ribbon" pattern stuff made
in the USA. It was not cheap, as you'd expect for plated solid brass,
but it was available.

Pete Keillor

unk

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Oct 15, 2017, 7:54:53 AM10/15/17
to
On Sun, 15 Oct 2017 01:36:55 +0000, bob prohaska wrote:

> Speaking of setup, holding the parts in position looks rather difficult;
> the broken tab is only about 1/8" square. Can anybody suggest some sort
> of putty that will resist brazing heat, hold the (very small) parts in
> place and not sinter to something indestructible when heated? Maybe
> glazier's putty, but that can get rather hard. Fire stop caulking?
> modeling clay? Perhaps something made from household chemicals like talc
> and water?
>

Does the tab, when not broken, have enough of a curve that a bit of brass
shim stock could be cut and shaped to lie on the outside of the curve and
hold the parts in place; solder all three together.

Neon John

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Oct 15, 2017, 9:54:02 AM10/15/17
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On Sun, 15 Oct 2017 01:36:55 -0000 (UTC), bob prohaska
<b...@www.zefox.net> wrote:


>Speaking of setup, holding the parts in position looks rather difficult;
>the broken tab is only about 1/8" square. Can anybody suggest some sort
>of putty that will resist brazing heat, hold the (very small) parts in
>place and not sinter to something indestructible when heated? Maybe
>glazier's putty, but that can get rather hard. Fire stop caulking?
>modeling clay? Perhaps something made from household chemicals like
>talc and water?

Welding putty. Sold at any well-stocked welding supply store.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address

Gunner Asch

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Oct 15, 2017, 3:32:39 PM10/15/17
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On Fri, 13 Oct 2017 23:09:11 -0400, cl...@snyder.on.ca wrote:

Ooooh! Really? Thanks!! Ill try that on one of my projects!

Gunner

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

Gunner Asch

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Oct 15, 2017, 3:35:28 PM10/15/17
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Heat it up and shoot compressed air into the joint. Solder comes right
out. It however will retain a molecules thick layer of
solder.."staining" the metal.

>
>Thanks very much for posting!
>
>bob prohaska

Martin Eastburn

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Oct 15, 2017, 6:32:26 PM10/15/17
to
One thing on large irons - Black Beauty and such -
My dad was trained on them back in the day of making vacuum tubes by hand.

Use the rubber on the inside of the boot heel to coat the parts of an
iron (or work). The rubber keeps flux from running solder around the
3/8" diameter tip of the Black Beauty.

I have used it many a time and it works nicely - stinks a bit but heck
soldering rubber coated wire and some plastics stinks also.

I used to have a 300 watt but only have 150 now. My large 1" large iron
was used to solder on steel and Aluminum chassis. Large irons are there
to provide more HEAT and thereby last longer at a given temp.

A small iron gets hot but cools off on some work. Consider soldering a
copper roof.

Martin

Bill

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Oct 15, 2017, 10:20:35 PM10/15/17
to
On Sun, 15 Oct 2017 01:36:13 -0400, Bill wrote:

> On Sun, 15 Oct 2017 01:36:55 -0000 (UTC), bob prohaska wrote:
>
>> It seems as if correction fluid might be a pretty good bet. Near as I
>> can tell the pigment is titanium dioxide, which is a fairly inert
>> ceramic. It can be applied thick, perhaps it'll resist flux. Shouldn't
>> be too hard to set up a rehearsal with some scrap brass for a test.
>>
>> Speaking of setup, holding the parts in position looks rather difficult;
>> the broken tab is only about 1/8" square. Can anybody suggest some sort
>> of putty that will resist brazing heat, hold the (very small) parts in
>> place and not sinter to something indestructible when heated? Maybe
>> glazier's putty, but that can get rather hard. Fire stop caulking?
>> modeling clay? Perhaps something made from household chemicals like
>> talc and water?
>>
>> Thanks for everyone's ideas!
>>
>> bob prohaska
>
> We used a soldering investment - something like this:
> https://whipmix.com/products/soldering-investments/
>
> Soldering investment can be used in very creative ways to make an
> "index" that would hold your parts in a predermined relationship while
> the actual brazing is done.

Here's a link to video of what was taught in dental schools 30 years ago
that you might be able to modify/adapt to fit your needs. It shows it
all. They're using hard, high strength, gold solder/braze. The brazing
temp is not far below the melting point of the gold being used.

Duralay, the material that was used to tempiorarily splint the bits
together is just a two part (liquid/powder) cold cure resin.

If you can find a suitable yellow colored, or gold solder, it might
eliminate most of the gray/silver discoloration that regular silver
solder can leave.

https://www.youtube.com/watch?v=7gcaGK5Zpnc

bob prohaska

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Oct 16, 2017, 1:56:38 AM10/16/17
to
Bill <2k7...@gmail.com> wrote:
>>
>> We used a soldering investment - something like this:
>> https://whipmix.com/products/soldering-investments/
>>
>> Soldering investment can be used in very creative ways to make an
>> "index" that would hold your parts in a predermined relationship while
>> the actual brazing is done.
>
> Here's a link to video of what was taught in dental schools 30 years ago
> that you might be able to modify/adapt to fit your needs. It shows it
> all. They're using hard, high strength, gold solder/braze. The brazing
> temp is not far below the melting point of the gold being used.
>
> Duralay, the material that was used to tempiorarily splint the bits
> together is just a two part (liquid/powder) cold cure resin.
>
> If you can find a suitable yellow colored, or gold solder, it might
> eliminate most of the gray/silver discoloration that regular silver
> solder can leave.
>
> https://www.youtube.com/watch?v=7gcaGK5Zpnc
>
Soldering investment looks like exactly what's required. Whether I
have the manual dexterity to use it successfully is another matter
entirely. The part I want to re-attach is slightly smaller than the
dental fillings shown in the video, but the pull base and ring are
quite a bit larger. That's not a good combination.

The video was absolutely fascinating. I can now understand why dental
work is so expensive. Thank you very much for posting it.

bob prohaska

bob prohaska

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Oct 16, 2017, 2:06:16 AM10/16/17
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Pete Keillor <Pete.K...@gmail.com> wrote:
> Do you have a jeweler's torch? You're going to need one. I wrecked a
> drawer pull about that size with my smallest torch.
>
I do not; I have a very tiny butane-air torch and a small acetylene-air
torch. The butane-air torch is probably too small, the acetylene-air
torch a trifle big. I think it's got the better chance, however.

> Given my prior experience, I'd have a long look for a suitable
> replacement, just in case. There are lots of cabinet hardware outfits
> still around. I got my sister some "reed & ribbon" pattern stuff made
> in the USA. It was not cheap, as you'd expect for plated solid brass,
> but it was available.

Fortunately, there's nobody breathing down my neck on this project. I broke
the pull and will be very pleased if I can fix it. If I can't fix it
neatly, I'll fix it less than neatly.....8-)

Thanks for writing!

bob prohaska

bob prohaska

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Oct 16, 2017, 2:10:56 AM10/16/17
to
unk <m...@privacy.net> wrote:
>
> Does the tab, when not broken, have enough of a curve that a bit of brass
> shim stock could be cut and shaped to lie on the outside of the curve and
> hold the parts in place; solder all three together.
>
That would certainly help prevent re-breaking the tab. However, I then
have one more part to locate correctly. Not sure I'm up for that.....

Thanks!

bob prohaska

bob prohaska

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Oct 16, 2017, 2:22:08 AM10/16/17
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Neon John <n...@never.com> wrote:
> Welding putty. Sold at any well-stocked welding supply store.
>
>
I tried "welding putty" among other terms in web searches and mostly
got references to epoxy-metal concoctions that seem rather ersatz.
I'll check with the local welding supply shops (Airgas and Trico in
Woodland) but I think dental soldering investment comes very close
to being what I need.

robobass

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Oct 16, 2017, 6:17:17 AM10/16/17
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If you solder on a flat tab successfully, then you should be able to bend it over the shaft after it has cooled. It will be well annealed. If it breaks while you're trying to bend it, then you want to get a better bond anyway. A few tries at this will still be less work than all of this barrier treatment stuff.

bob prohaska

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Oct 26, 2017, 11:34:57 AM10/26/17
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robobass <robanz...@gmail.com> wrote:
>
>
> If you solder on a flat tab successfully, then you should be able to bend it over the shaft after it has cooled. It will be well annealed. If it breaks while you're trying to bend it, then you want to get a better bond anyway. A few tries at this will still be less work than all of this barrier treatment stuff.

FWIW, the correction fluid made a reasonably effective barrier. My choice
of soldering investment was less clever; I used spackling compound, which
seemed fine until the soldering was done, whence it became clear the parts
moved. Not disastrously, but enough to see. Not sure if the movement happened
during the soldering, or during the several days it had to dry out. Shortly
after the parts were set up the gap was less than half what it ended up at.

There are a couple photos at
http://www.zefox.net/~bp/drawerpull/

Thanks to everyone who replied!

bob prohaska

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