Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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Old February 14th 04, 10:37 AM
The Hurdy Gurdy Man
 
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Default Electrolytic rust removal question


I've been reading through web pages and old posts about electrolytic rust
removal, and apparently using stainless as an electrode is a no-no due to
toxic waste concerns. As such, a "graphite rod" is the preferred thing.
My question is, when they say "graphite rod" do they mean any specific
type of graphite rod? Could I use rods for carbon arc welding, or
graphite rods used for EDM? Looks like Enco has graphite EDM rods on sale
(or at least they did a little while ago) and I've been wanting to try
removing some rust with this technique, but I'm not sure if these are the
rods I should/can be using or not. Thanks in advance for any assistance!

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Old February 14th 04, 01:06 PM
SRF
 
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Default Electrolytic rust removal question


Don't know where you read that but my electrode is a piece of rebar from
Home Depot. Works great.

Steve.


"The Hurdy Gurdy Man" wrote in message
...

I've been reading through web pages and old posts about electrolytic rust
removal, and apparently using stainless as an electrode is a no-no due to
toxic waste concerns. As such, a "graphite rod" is the preferred thing.
My question is, when they say "graphite rod" do they mean any specific
type of graphite rod? Could I use rods for carbon arc welding, or
graphite rods used for EDM? Looks like Enco has graphite EDM rods on sale
(or at least they did a little while ago) and I've been wanting to try
removing some rust with this technique, but I'm not sure if these are the
rods I should/can be using or not. Thanks in advance for any assistance!



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Old February 14th 04, 01:06 PM
Orrin Iseminger
 
Posts: n/a
Default Electrolytic rust removal question

On Sat, 14 Feb 2004 10:37:20 GMT, The Hurdy Gurdy Man
wrote:


I've been reading through web pages and old posts about electrolytic rust
removal, and apparently using stainless as an electrode is a no-no due to
toxic waste concerns. As such, a "graphite rod" is the preferred thing.
My question is, when they say "graphite rod" do they mean any specific
type of graphite rod? Could I use rods for carbon arc welding, or
graphite rods used for EDM? Looks like Enco has graphite EDM rods on sale
(or at least they did a little while ago) and I've been wanting to try
removing some rust with this technique, but I'm not sure if these are the
rods I should/can be using or not. Thanks in advance for any assistance!


Just find the cheapest source of graphite that you can. I found some
on eBay.

Whatever you use, remember this: a bit flat piece has much more
surface area than a rod. More surface area = more current. I got
lucky and found some big graphite blocks that I bandsaw into 1/2"
thick plates. (Move your saw outdoors for this. It's a messy job.
Don't set the saw on your driveway, either.)

There's a problem with searching for "graphite" on eBay. You'll get
thousands of listings of tennis racquets to golf clubs to fishing
poles. Instead, search for graphite plate*, graphite stock, graphite
bar*, etc. The * is a wild card that will give you hits on both plate
and plates.

The binder in some types of graphite doesn't hold up well in the
electrolysis vat. I've had some graphite plates dissolve in a day or
so. On the other hand, I've had some graphite last for a year, or
more, under continuous use.

If you have a foundry or mill that uses an electric arc furnace or an
aluminum smelter, nearby, see if you can beg some stub end of their
carbon rods.

Here's a tip: If you have a 3,000 psi pressure washer, use it for
removing the gunk that forms during electrolysis. It works great and
saves lots of elbow grease.

Good luck.

Orrin

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Old February 14th 04, 03:55 PM
Ed Huntress
 
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Default Electrolytic rust removal question

"The Hurdy Gurdy Man" wrote in message
...

I've been reading through web pages and old posts about electrolytic rust
removal, and apparently using stainless as an electrode is a no-no due to
toxic waste concerns. As such, a "graphite rod" is the preferred thing.
My question is, when they say "graphite rod" do they mean any specific
type of graphite rod? Could I use rods for carbon arc welding, or
graphite rods used for EDM? Looks like Enco has graphite EDM rods on sale
(or at least they did a little while ago) and I've been wanting to try
removing some rust with this technique, but I'm not sure if these are the
rods I should/can be using or not. Thanks in advance for any assistance!


First, I'm curious about what the toxic waste issue would be with stainless.
Do you have a link or a reference?

For swabbing, I use a 1.25" x .75" x 9" slab of Poco 3 (EDM graphite) that I
cut off an old EDM electrode with a hand saw. It cuts about like maple. EDM
graphite has no binders and Poco 3 is very dense and strong. It probably
will outlast me and the next two generations of my family. I just clamp the
battery clamp from my 4A battery charger to the end of it and wear rubber
gloves.

For use in a tank, my electrode is a plain sheet of mild steel (the cover
off an old microwave oven) that I sanded clean on one side with a disk
sander. Just wipe it dry when you're done. I see no need for stainless.
However, I do wonder about what could be toxic in using stainless for this
job.

Ed Huntress


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Old February 14th 04, 07:20 PM
Ted Edwards
 
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Default Electrolytic rust removal question

Ed Huntress wrote:

For use in a tank, my electrode is a plain sheet of mild steel (the cover
off an old microwave oven) that I sanded clean on one side with a disk
sander. Just wipe it dry when you're done. I see no need for stainless.
However, I do wonder about what could be toxic in using stainless for this
job.


Could be chromium. Also, you are talking about the *anode*. This is
the sacraficial electrode in plating so you will be eroding a metalic
anode into your solution thus conaminating it. You won't get the eroded
material plating out nicely - concentrations are all wrong for plating.
Graphite won't do that so is to be preffered for electrocleaning.

Ted




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Old February 14th 04, 08:44 PM
Ed Huntress
 
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Default Electrolytic rust removal question

"Ted Edwards" wrote in message
...
Ed Huntress wrote:

For use in a tank, my electrode is a plain sheet of mild steel (the

cover
off an old microwave oven) that I sanded clean on one side with a disk
sander. Just wipe it dry when you're done. I see no need for stainless.
However, I do wonder about what could be toxic in using stainless for

this
job.


Could be chromium. Also, you are talking about the *anode*. This is
the sacraficial electrode in plating so you will be eroding a metalic
anode into your solution thus conaminating it. You won't get the eroded
material plating out nicely - concentrations are all wrong for plating.
Graphite won't do that so is to be preffered for electrocleaning.


From my reading about the process (and I know little about electrochemistry
myself), it appears there is no erosion of metal involved at all, on either
side. That's why I question the idea that stainless causes a problem.

Ed Huntress


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Old February 14th 04, 11:25 PM
Mark Rand
 
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Default Electrolytic rust removal question

On Sat, 14 Feb 2004 20:44:15 GMT, "Ed Huntress"
wrote:


From my reading about the process (and I know little about electrochemistry
myself), it appears there is no erosion of metal involved at all, on either
side. That's why I question the idea that stainless causes a problem.

Ed Huntress


I have used stainless because I have some sheet which is about the right size.
I have neither seen or measured any loss from the stainless anode although it
is very obvious (from current variations) that one must run with reverse
polarity regularly to de-polarize the anode. I imagine that carbon would not
suffer from this problem???

Mark Rand
RTFM
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Old February 14th 04, 11:54 PM
ShadowHawk
 
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Default Electrolytic rust removal question

Do a google search on electrolysis, and you'll find quite a bit of info.
Here's one particular article written by a friend of mine - Richard
Angelico of New Orleans, La. He is a fellow relic-hunter who finds quite a
bit of good 'ole Civil War ordinance - specifically - he finds a good many
bombs and cannonballs.

He uses 316 stainless for his anode... and his results are fantastic.

Link to his article:
http://www.troycustomdetectors.com/s...ctrolysis.html

Rex S.

Mark Rand wrote in
:

On Sat, 14 Feb 2004 20:44:15 GMT, "Ed Huntress"
wrote:


From my reading about the process (and I know little about
electrochemistry myself), it appears there is no erosion of metal
involved at all, on either side. That's why I question the idea that
stainless causes a problem.

Ed Huntress


I have used stainless because I have some sheet which is about the
right size. I have neither seen or measured any loss from the
stainless anode although it is very obvious (from current variations)
that one must run with reverse polarity regularly to de-polarize the
anode. I imagine that carbon would not suffer from this problem???

Mark Rand
RTFM


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Old February 15th 04, 12:10 AM
Ed Huntress
 
Posts: n/a
Default Electrolytic rust removal question

"ShadowHawk" wrote in message
news:[email protected]_s53...
Do a google search on electrolysis, and you'll find quite a bit of info.
Here's one particular article written by a friend of mine - Richard
Angelico of New Orleans, La. He is a fellow relic-hunter who finds quite

a
bit of good 'ole Civil War ordinance - specifically - he finds a good many
bombs and cannonballs.


Some may be interested to know that they use this method to reduce rust and
to remove salt from metal objects recovered from ancient ship wrecks. The
time they leave it in the tank is often up to two YEARS. Yike.

Ed Huntress


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Old February 15th 04, 12:33 AM
Ed Huntress
 
Posts: n/a
Default Electrolytic rust removal question

"Mark Rand" wrote in message
...
On Sat, 14 Feb 2004 20:44:15 GMT, "Ed Huntress"
wrote:


From my reading about the process (and I know little about

electrochemistry
myself), it appears there is no erosion of metal involved at all, on

either
side. That's why I question the idea that stainless causes a problem.

Ed Huntress


I have used stainless because I have some sheet which is about the right

size.
I have neither seen or measured any loss from the stainless anode although

it
is very obvious (from current variations) that one must run with reverse
polarity regularly to de-polarize the anode. I imagine that carbon would

not
suffer from this problem???


I don't know, Mark. The people who seem to know what they're talking about
on this subject describe it as a very weak action, which won't even affect
black rust (Fe3O4). It only works on red rust. The weak alkaline solution
doesn't produce any significant quantity of ionized metal ions. It doesn't
do much of anything, in fact, except strip red rust somehow.

The black grunge that remains on the part is mostly black rust. It comes off
easily with a light brushing from a stainless brush. In a couple of cases
I've used hydrochloric acid to remove the black rust, and then put the part
back in the electrolytic process in the hope that it will remove any
chloride ions picked up from the acid.

I don't know. But I have a lot of de-rusted parts to show that it does a
good job.

Ed Huntress




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