rust
gearhead
develop a heavy coating of rust. It is ordinary cheap steel, not
galvanized. A coil of wire about 16 or 17 gauge. I already washed it
to get any oil off.
Just getting it wet and letting it sit will take much too long. I
need a way to speed up the reaction. I've thought of putting the
steel in water and applying a voltage to it like electrolytic
cleaning, but backwards. I've read that electrolytic rust removal
involves applying a negative voltage to the workpiece and placing a
positive sacrificial electrode in the solution. So presumably I could
reverse the polarity and apply positive voltage to the workpiece if I
want it to rust. But from what I've read about electrolytic cleaning,
the positive electrode actually dissolves -- and I don't want that.
Perhaps if I use plain water instead of an electrolyte, the positive
electrode would not dissolve. Or maybe there's some chemical I can
use on the steel that will make it start rusting right away, and I
wouldn't have to resort to electrolysis. I'm no chemist.
How would I go about this?
Mark Thorson
>
> I have some steel I just bought for a project. I need this steel to
> develop a heavy coating of rust. It is ordinary cheap steel, not
> galvanized. A coil of wire about 16 or 17 gauge. I already washed it
> to get any oil off.
The fastest way to rust something is to put it
in a pure oxygen atmosphere. Condensing a little
moisture on it will also speed up rust formation.
Michael Robinson
"Mark Thorson" <nos...@sonic.net> wrote in message
news:4A4EBF40...@sonic.net...
Unfortunately, I don't see an oxygen tank in the budget.
danger...@gmail.com
>...Or maybe there's some chemical I can
> use on the steel that will make it start rusting right away, and I
> wouldn't have to resort to electrolysis. I'm no chemist.
> How would I go about this?
Soft iron will rust pretty quickly under the right conditions. Put it
in a Ziplok plastic bag, with a few tablespoons of water, and put it
in a warm place overnight. Washing with paint thinner, soap and clean
water will remove any grease that will slow the process.
If you can use hydrogen peroxide instead of water, the rusting will
probably go much faster.
Dangerous Bill
gearhead
Good on the H2O2. Something to try, anyway.
What about acidic versus basic solutions, for example what effect
would you get by adding a few grains of lye? I expect it might not
help, just asking out of curiosity.
Salmon Egg
"Michael Robinson" <nos...@billburg.com> wrote:
Would 3% drugstore hydrogen peroxide do the job? I think it is worth a
trial.
Bill
--
Most people go to college to get their missing high school education.
Salmon Egg
<f39cb8a6-a0ab-4822...@b15g2000yqd.googlegroups.com>,
gearhead <nos...@billburg.com> wrote:
> Good on the H2O2. Something to try, anyway.
> What about acidic versus basic solutions, for example what effect
> would you get by adding a few grains of lye? I expect it might not
> help, just asking out of curiosity.
It would certainly help clean off any oils.
Carl Ijames
if you toss in some table salt.
-----
Regards,
Carl Ijames
"gearhead" <nos...@billburg.com> wrote in message
news:2d22b6a1-b85a-4975...@c36g2000yqn.googlegroups.com...
Marvin
Others have made some suggestions. But you may not succeed
in getting a heavy coating of rust. What makes rust
destructive is that the oxide tends to flake off the metal,
exposing more metal to rusting. On the other hand, aluminum
oxide sticks strongly to aluminum, so aluminum is often
coated by anodizing - creating a relatively thick oxide
layer by electrolysis. There is a special iron alloy that
forms adherent oxide layers. It allows rust to form, but the
rust doesn't destroy the metal because it doesn't flake off.
Rusting is an autocatalytic process, so the rate of rusting
increases once some rust has formed initially. That is why
it is so important to remove all rust before painting over
the metal.
Frank
I would consider one of the browning formulas from this site:
http://www.geocities.com/thorvin.geo/browning_and_blueing_of_guns_and.htm
Browning and gun blueing give controlled oxidation of iron surface and
also protect from further rusting.
gearhead
>
> Browning and gun blueing give controlled oxidation of iron surface and
> also protect from further rusting.
Okay, the reason I want rust on this wire is to act as electrical
insulation. I am winding the wire around a metal object and using the
wire as a heating element. If there is something other than rust,
easier or more effective, I'd be interested in knowing about it.
Would browning and bluing work as electrical insulation? I confess I
haven't read your link yet.
gearhead
>
> Browning and gun blueing give controlled oxidation of iron surface and
> also protect from further rusting.
It just happens I have some anhydrous ferric chloride powder. Your
link shows some formulas that include ferric chloride.
I submerged my coil of wire in drugstore hydrogen peroxide for a few
hours and it gathered noticeable rust, but it's kind of patchy. Maybe
I didn't do a good job cleaning the oil off.
I bought the ferric chloride to use as a copper etchant to make
printed circuit boards. Never got around to it. I might try it on
the steel wire and see what happens.
N:dlzc D:aol T:com (dlzc)
"gearhead" <nos...@billburg.com> wrote in message
news:3f6bc068-12f0-4e38...@q11g2000yqi.googlegroups.com...
On Jul 4, 11:50 am, Frank <frank.logu...@dol.net> wrote:
> On Jul 3, 10:22 pm, gearhead <nos...@billburg.com> wrote:
>
>> > I have some steel I just bought for a project.
>> > I need this steel to develop a heavy coating
>> > of rust. It is ordinary cheap steel, not
>> > galvanized. A coil of wire about 16 or 17 gauge.
>> > I already washed it to get any oil off.
>> I would consider one of the browning formulas
>> from this site:
>
<link now broken by Google.Groups>
>
>> Browning and gun blueing give controlled
>> oxidation of iron surface and also protect from
>> further rusting.
> Okay, the reason I want rust on this wire is
> to act as electrical insulation.
Rust is a very poor electrical insulator, among the lowest
resistivites of metal oxides.
> I am winding the wire around a metal object
> and using the wire as a heating element. If
> there is something other than rust, easier or
> more effective, I'd be interested in knowing
> about it.
nichrorme in alumina is the usual suspect for this, as iron does
not have a particularly high resistivity per foot. Even if you
rust it first. Additionally, it softens and breaks, spalling off
any "rust insulation", and does not run to as high a temperature
before fully oxidizing as nichrome can.
David A. Smith
Salmon Egg
<3f6bc068-12f0-4e38...@q11g2000yqi.googlegroups.com>,
gearhead <nos...@billburg.com> wrote:
> Okay, the reason I want rust on this wire is to act as electrical
> insulation. I am winding the wire around a metal object and using the
> wire as a heating element. If there is something other than rust,
> easier or more effective, I'd be interested in knowing about it.
> Would browning and bluing work as electrical insulation? I confess I
> haven't read your link yet.
Relying upon rust as an insulator is looking for trouble, I would be
very surprised if you do not get shorts much faster than you can cure
them.
I would expect that nichrome would be much more reliable, It does not
have insulation. Ceramic forms are available for winding nichrome
resistance wire spaced from adjoining turns. You could use formvar
coated copper wire if it is thin enough and what temperature you wish to
reach.
I once built a oven for growing organic scintillation crystals. The oven
itself was made from stainless steel cans. I coated it with some form of
sauereisen cement. I think that it may still be available. Nichrome was
hand wound on this coating, More sauereisen was used to cover the
nichrome and hold ity in place,
gearhead
> In article
> <3f6bc068-12f0-4e38-91da-9288be28c...@q11g2000yqi.googlegroups.com>,
>
> gearhead <nos...@billburg.com> wrote:
> > Okay, the reason I want rust on this wire is to act as electrical
> > insulation. I am winding the wire around a metal object and using the
> > wire as a heating element. If there is something other than rust,
> > easier or more effective, I'd be interested in knowing about it.
> > Would browning and bluing work as electrical insulation? I confess I
> > haven't read your link yet.
>
> Relying upon rust as an insulator is looking for trouble, I would be
> very surprised if you do not get shorts much faster than you can cure
> them.
>
> I would expect that nichrome would be much more reliable, It does not
> have insulation. Ceramic forms are available for winding nichrome
> resistance wire spaced from adjoining turns. You could use formvar
> coated copper wire if it is thin enough and what temperature you wish to
> reach.
>
varnish type insulation is copper magnet wire. Copper would not make
a good heating element.
I'm heating at least 12 ft of quarter inch tubing. Efficiency is
important; whatever I use to isolate the heating element from the
tubing needs to be as thermally conductive as possible. So I thought
of rust, but I guess that's just not a very good idea. I suppose it
would make more sense just to paint the tubing.
N:dlzc D:aol T:com (dlzc)
"gearhead" <nos...@billburg.com> wrote in message
news:d2b70579-0d3b-4e4f...@t21g2000yqi.googlegroups.com...
...
> Can't use ceramic forms, and the only wire I'm
> familiar with that has varnish type insulation is
> copper magnet wire. Copper would not make
> a good heating element.
> I'm heating at least 12 ft of quarter inch tubing.
How hot?
Can you use inductive heating?
Are you heating the tubing, or its contents?
Are the contents conductive, if not, pass current through the
tubing itself.
> Efficiency is important; whatever I use to isolate
> the heating element from the tubing needs to be
> as thermally conductive as possible. So I thought
> of rust, but I guess that's just not a very good idea.
It is extremely mechanically unstable. It adsorbs water from the
air.
> I suppose it would make more sense just to
> paint the tubing.
Most insulations will fracture with large temperature changes.
Can you "spill the beans", or are you going for some form of
patent...
David A. Smith
gearhead
wrote:
It's a personal project. Injection line heating for a diesel engine.
Not sure exactly what temp I'll use.
People that do vegetable oil conversions
cite temps in the 170F ballpark.
Six injection lines, each roughly 2 ft long,
grounded at each end.
So running DC through the tubing
to heat it is just not doable.
I'd have to attach the power at the center of each tube,
which amounts to 12 one foot tubes in parallel.
Just not doable at DC, resistance way too low.
Now, it's interesting that you mention induction heating.
I have an induction heating circuit I've been experimenting with.
It works pretty well. A self-resonating push-pull circuit, runs off
12 volts.
When I set it up on the bench it gets steel rods very hot very fast.
I can regulate it with a thermistor.
I should just bite the bullet and do the work to develop and install
this
on the truck, but it's a lot more effort than your average weekend
project
of just wrapping some resistance wire around the injection lines.
N:dlzc D:aol T:com (dlzc)
"gearhead" <nos...@billburg.com> wrote in message
news:95605e0c-39bd-450f...@h8g2000yqm.googlegroups.com...
On Jul 5, 12:53 am, "N:dlzc D:aol T:com \(dlzc\)" <dl...@cox.net>
wrote:
...
>> How hot?
>> Can you use inductive heating?
>> Are you heating the tubing, or its contents?
>> Are the contents conductive, if not, pass current
>> through the tubing itself.
...
> It's a personal project. Injection line heating for
> a diesel engine.
> Not sure exactly what temp I'll use.
> People that do vegetable oil conversions
> cite temps in the 170F ballpark.
Not too bad.
> Six injection lines, each roughly 2 ft long,
> grounded at each end.
> So running DC through the tubing
> to heat it is just not doable.
> I'd have to attach the power at the center of
> each tube, which amounts to 12 one foot
> tubes in parallel. Just not doable at DC,
> resistance way too low.
Well, DC-to-DC conversion could be just the trick, but I'd have
no clue how to do it.
> Now, it's interesting that you mention
> induction heating. I have an induction
> heating circuit I've been experimenting with.
> It works pretty well. A self-resonating
> push-pull circuit, runs off 12 volts. When
> I set it up on the bench it gets steel rods
> very hot very fast.
> I can regulate it with a thermistor.
Yes. You could switch your circuit on and off...
> I should just bite the bullet and do the
> work to develop and install this on the truck,
> but it's a lot more effort than your average
> weekend project of just wrapping some
> resistance wire around the injection lines.
Proof of concept?
David A. Smith
danger...@gmail.com
> I bought the ferric chloride to use as a copper etchant to make
> printed circuit boards. Never got around to it. I might try it on
> the steel wire and see what happens.
Rust is a bad, bad idea for insulation. It's mechanically unsound, and
will become less so on repeated heating. It's permeable to moisture,
which isn't going to help.
You can buy glass-fiber (not Fiberglas) insulated wire from Omega
Engineering. Like this one:
http://www.omega.com/pptst/HTGG-1NI.html
Fish around their site for awhile. I'm sure they have nichrome or
chromel resistance wire with glass covering. This will do the job for
you. I've done something like this for scientific instruments in the
past.
For this kind of application, breaking the wire into short semi-
independent lengths is a good approach. Trying to heat a long stretch
of resistance wire can be difficult for several reasons. Pulsing the
DC as David suggested is the best way to control the power applied
without wasting it, although it may cause some electrical interference
in nearby radios.
Dangerous Bill
Salmon Egg
<d2b70579-0d3b-4e4f...@t21g2000yqi.googlegroups.com>,
gearhead <nos...@billburg.com> wrote:
> Can't use ceramic forms, and the only wire I'm familiar with that has
> varnish type insulation is copper magnet wire. Copper would not make
> a good heating element.
>
> I'm heating at least 12 ft of quarter inch tubing. Efficiency is
> important; whatever I use to isolate the heating element from the
> tubing needs to be as thermally conductive as possible. So I thought
> of rust, but I guess that's just not a very good idea. I suppose it
> would make more sense just to paint the tubing.
There used to be muffle furnace heaters, but I do not know how small
they come.
There also were heater tapes you could wind around what you are heating.
Why not just have a hot reservoir with thermally insulated tubing?
Think out of the box. Using rust is certainly out of the box, but also
crazy.
Frank
>
> - Show quoted text -
As others point out, rust is not good for electrical resistance.
Maybe you can buy a heating tape which can be used for your purpose.