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oldjim
12-11-2012, 12:59 PM
I have used the last box of washing soda in my stash for the process and no one around here carries it any more. Are any of you guys using something else for making the electrolyte?
Thanks
Jim

chucketn
12-11-2012, 01:06 PM
I think the last box I bought came from the dollar store.

Chuck

bborr01
12-11-2012, 01:09 PM
Hi Jim,

I just took a box of regular baking soda, spread it around on a cookie sheet about 1/4 inch deep and baked for 1 hour at 300 degrees F. There is a molecular conversion that happens. I have used it with great success.

Brian

JFLingg
12-11-2012, 01:11 PM
I use Oxi-clean Versatile Stain Remover. Find it where the laundry detergents area. Contains sodium percarbonate and sodium carbonate per plastic tub labelling. Sodium carbonate is washing soda. Use same amount as you have been.

JFLingg

Jaakko Fagerlund
12-11-2012, 01:46 PM
Or just find a chemical suplier and ask for sodium carbonate, probably cheaper in a bag than the 'washing soda'.

Evan
12-11-2012, 01:57 PM
Lye works fine and it doesn't take much. Talk to your local Lutefisk supplier. http://ixian.ca/pics9/biggrin.gif

lugnut
12-11-2012, 02:02 PM
I don't know where you live that you can't buy A&H washing soda, but here in Oregon it is available at almost any grocery store, I use it to make Home Laundry soap on a regular basis . Cost is about $2.75 for a large box.

metalmagpie
12-11-2012, 02:16 PM
Hi Jim,

I just took a box of regular baking soda, spread it around on a cookie sheet about 1/4 inch deep and baked for 1 hour at 300 degrees F. There is a molecular conversion that happens. I have used it with great success.

Brian

If you were able to convert sodium bicarbonate into potassium bicarbonate with a little heat, I suggest you tackle the problem of converting lead to gold. Might be profitable for a man of your obvious talent.

flylo
12-11-2012, 02:19 PM
I have used the last box of washing soda in my stash for the process and no one around here carries it any more. Are any of you guys using something else for making the electrolyte?
Thanks
Jim
Ace Hardware stocks it here & shows it on there website as free ship to store.

kitno455
12-11-2012, 04:23 PM
Washing soda is sodium carbonate.

allan

ed_h
12-11-2012, 04:24 PM
If you were able to convert sodium bicarbonate into potassium bicarbonate with a little heat...

Metal--

Washing soda is normally Sodium Carbonate. The conversion of Sodium Bicarbonate to Carbonate is done easily with heat. The reaction gives off Carbon Dioxide and water vapor.

john hobdeclipe
12-11-2012, 05:44 PM
Go to either a big borg store or a swimming pool supply store. One of the chemicals used to adjust the ph in swimming pools is 98% sodium carbonate. The last time I bought it, it was at the big orange store, and much cheaper than washing soda anywhere else. Sorry, but I've forgotten the brand of the stuff, but all you need to do is start reading the labels 'til you find the one that's sodium carbonate.

While we're on the subject: When you mix up your electrolyte, forget all of the formulas for so many ounces of soda per gallon of water. Just mix up a saturated solution by adding in the powder until no more will dissolve.

bborr01
12-11-2012, 06:21 PM
If you were able to convert sodium bicarbonate into potassium bicarbonate with a little heat, I suggest you tackle the problem of converting lead to gold. Might be profitable for a man of your obvious talent.

Now that was pretty rude. No, I mean what a jerk.

I read that is one way of making washing soda and tried it. It worked fine and I have used it many times.

Did you get up on the wrong side of the bed this morning? Or have you always been that way?

Brian

edit: maybe you are not allowed to use anything as complicated as an oven.

Fasttrack
12-11-2012, 06:43 PM
Why the insistence on washing soda? I use regular sodium bicarbonate (baking soda) without bothering to change it into sodium carbonate. The pH of the electrolyte solution is less basic so a metal part left to soak with the current turned off may rust but beyond that, I don't notice any difference in performance.

I usually dissolve some TSP into the solution as well. This works great if you have a rusty part that is partially covered in grime or paint.

macona
12-11-2012, 07:07 PM
I use TSP as an electrolyte for anodizing titanium so it should be fine for de-rusting as well.

lakeside53
12-11-2012, 07:12 PM
Don't use the current Arm and Hammer washing soda with considerable caution. It's available everywhere in supermarket laundry isles. You can ID it easily - the marketing gurus renamed the ingredients to "activated baking soda" (what crock of crap - it's still sodium carbonate) and loaded it up with detergents that foam.

You can buy 100% sodium carbonate at any pool/spa place -it's often called "ph adjuster". The other common bulk name is "Fly Ash".


Why not use the new A&H washing soda? Memories are short....


http://i238.photobucket.com/albums/ff150/lakeside53/misc%20linked%20uploads/DSCN2688Medium.jpg


so read this again :http://bbs.homeshopmachinist.net/threads/54891-Electrolysis-that-went-wrong?

bborr01
12-11-2012, 07:15 PM
Why the insistence on washing soda? I use regular sodium bicarbonate (baking soda) without bothering to change it into sodium carbonate. The pH of the electrolyte solution is less basic so a metal part left to soak with the current turned off may rust but beyond that, I don't notice any difference in performance.

I usually dissolve some TSP into the solution as well. This works great if you have a rusty part that is partially covered in grime or paint.

Fasttrack,

I use washing soda because that is what I read on this forum to use. I never tried it with plain baking soda because it was not that big of a deal to bake it. Never thought of putting tsp in it too. I wonder if the washing soda has to do with gassed produced.

Brian

lakeside53
12-11-2012, 07:23 PM
You can use baking soda, but it takes a lot more then washing soda for the same current density at a given voltage. If your power supply is limited in current or has plenty of voltage it might not matter. I use about 1.5 table spoons per gallon of washing soda (Sodium carbonate). You need a LOT less Lye (like 1/4 to 1/2 tsp per gallon), but... I slop it all over and like to get my hands in, so I don't use it anymore.

As has a been discussed above, you can convert baking soda to washing soda by heating in a tray to 350F for 15 minutes or so.

mhooper
12-11-2012, 07:57 PM
I've used "HTH Spa pH increaser" it is 97% sodium carbonate. I buy it at the local Walmart.
Works pretty good and is cheap.
Hint: remove all the grease and oil before starting the removing rust process . Oil and grease tends to block or slow down the electrolytic process, also makes a mess on the walls of your tank or container.

mhooper

Bluechips
12-11-2012, 07:57 PM
I get mine in the swimming pool section of the local hardware store too. No stores around here carried Washing Soda by name and could not or would not order it.

I've also used the oven trick with the baking soda before I found it at the hardware store. It works, but the store bought stuff is cheap.

metalmagpie
12-11-2012, 08:00 PM
Now that was pretty rude. No, I mean what a jerk.

I read that is one way of making washing soda and tried it. It worked fine and I have used it many times.

Did you get up on the wrong side of the bed this morning? Or have you always been that way?

Brian

edit: maybe you are not allowed to use anything as complicated as an oven.

OK, my bad. I apologize. Yes, I did in fact get up on the wrong side of the bed. I'm not usually an a**hole. Just sometimes.

metalmagpie

mickeyf
12-11-2012, 09:28 PM
Thanks especially for the "reminder" link. Not sure how I missed it the first time around. It's timely for me - I'm just getting geared up to try this process out for the firs time. Real Soon Now. I have a tank set up, but I was debating on whether to put together a power supply that gave me a bit more control and metering than a battery charger, or to just go for it.

lakeside53
12-11-2012, 09:37 PM
The best power supply is an adjustable constant current source. Mine's 0-30 amp and 0-30 volt. I turn the volts up and peg the current where I want. As the anode gets dirty the voltage will rise but the current stays the same (within limits). Higher current is good for larger surface areas and blowing of old paint, but they all get the job done eventually.

bborr01
12-11-2012, 09:53 PM
OK, my bad. I apologize. Yes, I did in fact get up on the wrong side of the bed. I'm not usually an a**hole. Just sometimes.

metalmagpie

Apology accepted.

Brian

ed_h
12-11-2012, 10:44 PM
The best power supply is an adjustable constant current source. Mine's 0-30 amp and 0-30 volt. I turn the volts up and peg the current where I want. As the anode gets dirty the voltage will rise but the current stays the same (within limits). Higher current is good for larger surface areas and blowing of old paint, but they all get the job done eventually.

For plating or anodizing, a good quality constant current supply is great, but this process is so down-and-dirty and so forgiving, it would probably be a waste of money to buy a special supply.

lakeside53
12-11-2012, 11:47 PM
But.. constant current pretty much comes for free on most decent power supplies. I was looking for a high power versatile psu - plating and/or plating removal is next on the list. In any case, I like CC for the control thoughout the process. Also great for bringing back DEAD FLAT car batteries when the wife leaves the interior light on!

$259 for a full featured 900W supply isn't too bad :http://www.mastechpowersupply.com/dc-power-supply/switching-power-supply/mastech-variable-power-supply-30v-30a-hy3030e-900w-high-current/prod_19.html

Many more to choose from.

Fasttrack
12-12-2012, 12:49 AM
You can use baking soda, but it takes a lot more then washing soda for the same current density at a given voltage.

As has a been discussed above, you can convert baking soda to washing soda by heating in a tray to 350F for 15 minutes or so.

That's a silly thing to do, imho. Not only will you have to cook the same amount of baking soda as you could you use without baking, but now you are spending the extra time and energy cooking it. The reason washing soda requires less is because it provides two sodium ions per molecule. Baking soda only yields one sodium ion so, to get the same electrolyte density, you have to use roughly twice as much baking soda as washing soda. When you cook baking soda to form washing soda, you are reducing its mass. The number of sodium ions available before cooking and after cooking is the same.



Fasttrack,

I use washing soda because that is what I read on this forum to use. I never tried it with plain baking soda because it was not that big of a deal to bake it. Never thought of putting tsp in it too. I wonder if the washing soda has to do with gassed produced.

Brian

Once you put it in water, washing soda and baking soda produce the same results except that one will generate a higher a pH solution. Baking soda dissolves leaving HCO3- as an ion, which is a pretty weak base. It will strip a few hydrogen atoms off of the a few water molecules to form H2CO3 and OH- but not very many. In the case of washing soda, it dissolves yielding CO3-- which is a stronger base. It will strip a fair number of water molecules of a hydrogen yielding quite a bit more OH- in the solution. Lye is NaOH so it yields nothing but OH- and Na+ when dissolved. The OH- ions are what determine the pH of the solution and the more of those there are, the less likely the steel will rust once the current is shut off.

I think I read the TSP trick on the forum from David Cofer (Dawai) maybe? Like I said, it works very well on greasy/grimy parts that are partially rusted or when you have a part that is half rust half paint.

ed_h
12-12-2012, 12:56 AM
But.. constant current pretty much comes for free on most decent power supplies. I was looking for a high power versatile psu - plating and/or plating removal is next on the list. In any case, I like CC for the control thoughout the process.

lake--

If plating and anodizing are on the horizon, that supply will be a great start. My point was that for just derusting, I can't think of any advantage the CC or the extra control will offer.

lakeside53
12-12-2012, 01:15 AM
Here's one example . My friend uses steel rather than lead (like I do) as an anode. For a large brake drum set last week, with clean anodes, it took 9.5 volts to drive 12 amps. The voltage limit was turned up to max (still 9.5 output) and current held at 12 amps. Pretty vigours bubbling. After 24 hours the anodes were filthy, the voltage had risen to 28 volts, still 12 amps. A few more hours and the voltage would have pegged to 30 and the current started to fall off.

If the power supply was say 30 volts, with no current limiting other than "max", it would have immediately pegged current at 30 amps. Way too vigorous for my liking, and 900w into the barrel would have over-heated the solution rapidly! I like being able to control the current and voltage to limit the power entering the process and know it will stay how I set it.

The relationship between voltage and current is not linear - a very small change in voltage beyond the start of conduction will give a large change in current. Just fixing the voltage at say 10 volts means the current falls off as the anodes clog. A lot messing around. Of course, it will all get done eventually.

I suspect that many using battery chargers are in CC mode for much of the process whether they know it or not.

Connecting a car battery (to a fool a "smart charger" - some "internet advice" says to do this..) to a bath with a decent amount of anode and cathode can create huge intial currents. Frigg... at least put some car headlight light bulbs in series-parallel between the battery and bath. My advise to all is "know" or measure what current you have...

Bluechips
12-12-2012, 08:38 PM
I've started using carbon for the anodes. Actually, they're old industrial generator brushes.

They do not get corroded like steel does and the current stays pretty constant no matter how long I let the process go.

I've added a little TSP (trisodium phosphate) to the soda water if the part was greasy. Cleans good, but gets the water nasty.

I have good results at about 8 - 10 amps. I use a big commercial battery charger and adjust the voltage until I get the current in that range. Then I just forget about it for a couple of days if it's a big part. I do have to keep a check on the water level since it will drop as the water breaks down into hydrogen and oxygen.

On odd shaped parts, I try to get the anodes positioned for "line of sight" to the corrosion. I've read some discussion about if this not being neccesary, but it does seem to speed up the process. For instance, on a lathe chuck I did, the center hole didn't want to get clean. The outside of the piece looked good. I put a seperate anode through the hole and the bore was clean in short order.

Mike

ed_h
12-13-2012, 12:44 AM
On odd shaped parts, I try to get the anodes positioned for "line of sight" to the corrosion. I've read some discussion about if this not being neccesary, but it does seem to speed up the process. Mike

Mike--

The ability for these electrochemical processes to get into recesses is called "throwing power". I think one way it is measured is by how far the action goes into a hole. In plating, it varies quite a bit with the bath chemistry. This would make a great thing to test (if I had time)--differences in throwing power in derusting with different electrolytes at different concentrations.

BigJohnT
12-13-2012, 06:41 AM
Is there a link to how the whole process works? From reading the posts I gather that a power supply is needed and a mention of a battery charger tells me that it is a DC power supply. Also I gather that an anode is needed and solution of sodium carbonate. Also there seems to be some importance to knowing the current for some reason. I have a combination square that needs cleaning up...

John

flylo
12-13-2012, 07:54 AM
Here;s one I found John!
http://www.oldengine.org/members/orrin/rustdemo.htm
Also I have a 12"x3/4" carbon plate instead of steel & a plastic 55 gallon barrel on it's side.
Youtube has alot also.

BigJohnT
12-13-2012, 07:57 AM
Thanks I didn't even know what to search for... just finished reading that link and it is very informative.

John

flylo
12-13-2012, 08:01 AM
I have a new 28v power supply from the Air Force that weighs 800#+, if I had a pool I could make one to de-rust an entire truck!:rolleyes: LOL!

lakeside53
12-13-2012, 11:55 AM
If you need to derust a truck (or something with large surface area) use your tig welder as a constant current power supply. Like the problem with modern "smart" battery chargers, you might need an older "dumb" welder.

Grind Hard
12-13-2012, 12:02 PM
I have a new 28v power supply from the Air Force that weighs 800#+, if I had a pool I could make one to de-rust an entire truck!:rolleyes: LOL!

In another recent thread we saw some old vintage steam tractors that were rusted solid.

One wonders... given a large crane, a concrete bottom pool and a sufficiently large power supply if one could clean up such a thing with this method.

Only reason I ask.. I know of a very large concrete pool that sits abandoned. On paper... given the right permits, permissions and sufficient funding... could it be turned into the grandpappy of all de-rusting tanks.

Haz-mat disposal from such an operation would be the killer, you'd need a wastewater pre-treatment rig and more than likely an evaporator on site to deal with the mess... and some way to handle the sludge.

flylo
12-13-2012, 12:38 PM
I picked this power supply up for $50 from someone moving & it was the last thing in their storage unit. It's new AF surplus & I hate to open it up for the copper. I found a used on on Ebay for $2800, contacted the seller but he had no isea of the use either.

ed_h
12-13-2012, 12:52 PM
if I had a pool I could make one to de-rust an entire truck!:rolleyes: LOL!

Somewhere on the internet is a story with pictures of a guy who derusted a truck frame in a shallow tank.

BigJohnT
12-13-2012, 01:19 PM
I picked this power supply up for $50 from someone moving & it was the last thing in their storage unit. It's new AF surplus & I hate to open it up for the copper. I found a used on on Ebay for $2800, contacted the seller but he had no isea of the use either.

I think those were left over from the Philadelphia Experiment.

John

BigJohnT
12-13-2012, 04:44 PM
I found TSP in the paint department of a local lumber yard for $2.50 a pound... I have some carbon gouging rods I might cut them up and wire a bunch together to see if that works as the anode.

John

ed_h
12-13-2012, 05:39 PM
Somewhere on the internet is a story with pictures of a guy who derusted a truck frame in a shallow tank.

Here it is. It was a trailer frame:

http://antique-engines.com/trailer-electrolysis.htm

lakeside53
12-13-2012, 09:07 PM
I found TSP in the paint department of a local lumber yard for $2.50 a pound... I have some carbon gouging rods I might cut them up and wire a bunch together to see if that works as the anode.

John

If they are copper plated (most around here are now) you should remove the copper first (electrolysis, acid..)

oldjim
12-13-2012, 11:24 PM
Thanks guys, some of the suggestions enabled me to track down 3 boxes (the last 3 in the store) of A&H washing soda. It seems like Oxyclean is now replacing washing soda in the local super markets and big box stores in this area.

Reading the label tells me that Oxyclean is mainly sodium percarbonate.

Wikipedia says; "Sodium percarbonate is a chemical, an adduct of sodium carbonate and hydrogen peroxide (a perhydrate), with formula 2Na2CO3."

Since washing soda appears to becoming harder to locate in this neck of the woods nowdays, do you guys think Oxyclean would be as good as (or possibly better) for future electrolyte brews .

Thanks for all the good info.
Jim

BigJohnT
12-14-2012, 07:19 AM
If they are copper plated (most around here are now) you should remove the copper first (electrolysis, acid..)

Just to get more surface area?

The chap in the link seemed to think "In my experience, brass, copper, and bronze pieces are not seriously harmed" in the context of having other metals attached to the steel part being cleaned.

John

BigJohnT
12-14-2012, 07:25 AM
Thanks guys, some of the suggestions enabled me to track down 3 boxes (the last 3 in the store) of A&H washing soda.

Did you look in the paint dept of hardware stores for TSP?

John

Deepest_Valley
12-14-2012, 09:59 AM
Just a word about the chemistry of this electrolysis. The solution needs to be alkaline so that it conducts the current and you can use baking soda. When the power is first applied the solution will fizz. The baking soda is converting to soda ash. You will need to use twice as much baking soda as washing soda to get the same strength solution. OxyClean works the same way, it just more expensive. One word of caution, don't use anything with salt in it. Chloride is not good on iron. Think of what seawater does to iron and steel.

Max
retired from a soda ash plant

lakeside53
12-14-2012, 11:48 AM
Just to get more surface area?

The chap in the link seemed to think "In my experience, brass, copper, and bronze pieces are not seriously harmed" in the context of having other metals attached to the steel part being cleaned.

John No... to expose the carbon. Your statement is true if on the part to be cleaned, but the copper is on the anode and will be attacked by the oxygen produced. Someone else will have to get into the chemistry to determine is anything hazadous (i.e you can't toss it out in the yard) is produced.

BigJohnT
12-14-2012, 12:00 PM
No... to expose the carbon. Your statement is true if on the part to be cleaned, but the copper is on the anode and will be attacked by the oxygen produced. Someone else will have to get into the chemistry to determine is anything hazadous (i.e you can't toss it out in the yard) is produced.

That's why I quoted what he said (not me) in context. And that makes sense not to use it on the anode. I think for my first run I'll just use a piece of scrap steel for an anode. I assume if I use hot roll you don't want mill scale on it???

On another note our local walmart carries A&H washing powder for about $1/lb. I got so excited that I found sodium carbonate that I forgot to get the trash bags that I went in for...

John

Alistair Hosie
12-14-2012, 12:04 PM
Yeh I have top agree the regular baking soda sounds a bit iffy But then maybe it works I have never tried it but with my basic chemistry skills I can't see how myself. Alistair

lakeside53
12-14-2012, 12:06 PM
But take care with the A&H - it will most likey be the "new" type with tons of detergents in it causing it to create explosive foam. Look at the packet -if it it says "activated baking soda" it's the newer type. If you are at Walmart, just go over to the pool supplies dept and get the pool PH adjuster...


Don't worry about the mill scale. The anode will soon be a rusty mess. Use something "flat" so it's easier to wipe off every few days.

BigJohnT
12-14-2012, 12:10 PM
I just looked at McMaster and graphite bars are not terribly expensive a 1/4" x 1" x 12" bar is about $15 and according to what I've read graphite anode makes less of a mess in the tank.

Waddauguysthink?

John

lakeside53
12-14-2012, 12:27 PM
Depends on what you are doing. If it's a small bath by all means use the graphite, but.... do anything larger and you'll go broke. You need surface area to drive current at reasonable voltages. Larger surface areas give better throw, and.. need cleaning less often. I have about 400 sq inches of lead in my big barrel... (Stays clean'ish , but lead may slowly convert to lead carbonate - toxic).

I suggest you "just get started" and fine tune the process when you really get into it. And...just use the scrap steel - it will work fine. When it's almost consumed (converted to rust) toss it and throw in another.

If you want to use carbon/graphite, get the very much cheaper copper coated Gouging rods and strip them.

BigJohnT
12-14-2012, 01:21 PM
But take care with the A&H - it will most likey be the "new" type with tons of detergents in it causing it to create explosive foam. Look at the packet -if it it says "activated baking soda" it's the newer type. If you are at Walmart, just go over to the pool supplies dept and get the pool PH adjuster...


Don't worry about the mill scale. The anode will soon be a rusty mess. Use something "flat" so it's easier to wipe off every few days.

Walmart in their infinite wisdom won't have any pool supplies out till spring... things like canning jars only show up in summer... they will have aisle after aisle of the same holiday junk but not have one shelf for pool supplies go figure.

I'll just grab a bit of HR flat and use that to get going.

John

Bluechips
12-14-2012, 03:44 PM
I had decent luck with the steel anodes, but as they got corroded, the current flow went down. A quick cleaning got the amps back up. I like the carbon because it doesn't get corroded and I could set and forget about it.

I did put a 30 amp fuse in the circuit just in case some thing shorted out while I wasn't around.

As far as the TSP goes, I only add it for greasy parts. The straight sodium carbonate electrolite works for simple rust.

One other thing to point out. If you have pitted parts when you start, you're going to have derusted pitted parts when you're finished.:) This process just removes the rust, can't fix the damage.

Mike

spongerich
12-14-2012, 08:03 PM
No... to expose the carbon. Your statement is true if on the part to be cleaned, but the copper is on the anode and will be attacked by the oxygen produced. Someone else will have to get into the chemistry to determine is anything hazadous (i.e you can't toss it out in the yard) is produced.

It's generally not a good idea to introduce any heavy metals into your solution if you can avoid it. I've used copper wire to make my connections in the past and the copper also makes a green slimy mess.

I switched to graphite anodes and I'd never go back to steel. They last 20x longer and make 1/10th of the mess. Plus since they don't crust up, you can leave them running. I had an anvil in my tank for a whole week.

lakeside53
12-14-2012, 08:30 PM
Walmart in their infinite wisdom won't have any pool supplies out till spring... things like canning jars only show up in summer... they will have aisle after aisle of the same holiday junk but not have one shelf for pool supplies go figure.


John

Find a spa pool hot tub store. They always stock it.

cameron
12-14-2012, 09:29 PM
That's why I quoted what he said (not me) in context. And that makes sense not to use it on the anode. I think for my first run I'll just use a piece of scrap steel for an anode. I assume if I use hot roll you don't want mill scale on it???

On another note our local walmart carries A&H washing powder for about $1/lb. I got so excited that I found sodium carbonate that I forgot to get the trash bags that I went in for...

John


Don't worry about the mill scale, it won't be there for very long.

BigJohnT
12-15-2012, 07:25 AM
One other thing to point out. If you have pitted parts when you start, you're going to have derusted pitted parts when you're finished.:) This process just removes the rust, can't fix the damage.

Mike

That seems to be a common myth for the unknowing about sand blasting too...

John

BigJohnT
12-15-2012, 07:27 AM
It's generally not a good idea to introduce any heavy metals into your solution if you can avoid it. I've used copper wire to make my connections in the past and the copper also makes a green slimy mess.

I switched to graphite anodes and I'd never go back to steel. They last 20x longer and make 1/10th of the mess. Plus since they don't crust up, you can leave them running. I had an anvil in my tank for a whole week.

How much graphite anode surface area do you need vs the part being cleaned?

John

lakeside53
12-15-2012, 11:59 AM
It depends on how much current you want for a given voltage, how long you want the process to run and how much "line of sight" you want to achieve (rotating the object is easy for small, but can be painful for larger or heavy. "One" narrow anode is only going to see one side of the item. 3 or 4 would be better, continous lining of the tank is the other extreme.

BigJohnT
12-15-2012, 01:21 PM
It depends on how much current you want for a given voltage, how long you want the process to run and how much "line of sight" you want to achieve (rotating the object is easy for small, but can be painful for larger or heavy. "One" narrow anode is only going to see one side of the item. 3 or 4 would be better, continuous lining of the tank is the other extreme.

How much current do I need?

Right now it is a 12v charger so it will be 14-15v and without grinding off the mill scale it showed 2 amps more or less. After grinding one side clean of mill scale it showed double the amps... must be more to the story than don't worry about mill scale.

In any case it is bubbling along the length of the ruler and junk is starting to form on the top of the electrolyte.

Edit: my electrolyte is 6 gallons of water and 1/2 cup of sodium carbonate.

John

lakeside53
12-15-2012, 08:23 PM
The mill scale is quickly turned to rust and it comes off. Don't worry about scale - just use more sacrifical iron if you want higher initial currents.

Current required is about time (how long do you have?) and area, or current density in ma per square inch. For a ruler, 2 amps is plenty. If you even had 0.25 amp or 20ma, it would still work; just takes longer. Some studies of restoration work show microamps can deposit pure iron back to the item preserving very fine details, but that can take months to years. I did a truck brake drum with less then 2 amps in a couple of days. Higher current densities are good for blowing off old paint.

Bluechips
12-15-2012, 08:38 PM
I usually shoot for around 8-10 amps. My battery charger has several taps for various voltages. I just run the voltage up until I get the current where I want it.

It doesn't have to be exact. You can go higher, but it doesn't seem to speed the process up. The higher voltage and current does cause the water level to drop faster.

For safety, be sure to set this up in a well ventilated area. Remember you are generating highly flammable hydrogen and oxygen.

I read somewhere on the net about a guy that tried to use a welding machine and very high amps. He literally had the water boiling! A few minutes later he had a fire that melted his bucket.

Mike

vph
12-15-2012, 10:48 PM
http://well.ca/products/eco-pioneer-pure-washing-soda_30246.html

Rex
12-18-2012, 04:39 PM
Frankly, I haven't had a ot of luck with electrolytic. After reading this thread last week I decided to give it another go.
I'm cleaning a south bend Shaper. I used a 30-gallon plastic barrel, some lawnmower blades and plates for anodes, 6V manual charger for power.
I used 5 lbs of Soda Ash and about a cup of TSP. I left each batch overnight, the water was moving around, scum was coming up. I tried both 6V and 12V, both showing 4 amps or more.
I did the base, ram and cross-slide.
It loosened the paint, removed most of the rust, but still wasn't as clean as I wanted it.
So I soaked them in Evaporust and got the results I was looking for.

I'm going to order another 3 gallons of Evaporust to do the main housing.
Much less hassle, better results, more money.

ed_h
12-18-2012, 05:04 PM
Rex--

I'm glad you posted that. I, too, have tried the electrolytic process, and though is seemed to work OK, I don't understand all the irrational exuberance over it. I find phosphoric acid to be faster, less messy, just as effective, and no more expensive. I haven't tried Evaporust, but I hear it works very well, too.

I especially don't understand the current fad of using electrolysis for things like the inside of motorcycle tanks. Being a more or less line of sight process with limited throwing power, electrolysis will be least effective in the places in the tank most difficult to see, leading to a false sense of success.

Black_Moons
12-18-2012, 05:10 PM
Frankly, I haven't had a ot of luck with electrolytic. After reading this thread last week I decided to give it another go.
I'm cleaning a south bend Shaper. I used a 30-gallon plastic barrel, some lawnmower blades and plates for anodes, 6V manual charger for power.
I used 5 lbs of Soda Ash and about a cup of TSP. I left each batch overnight, the water was moving around, scum was coming up. I tried both 6V and 12V, both showing 4 amps or more.
I did the base, ram and cross-slide.
It loosened the paint, removed most of the rust, but still wasn't as clean as I wanted it.
So I soaked them in Evaporust and got the results I was looking for.

I'm going to order another 3 gallons of Evaporust to do the main housing.
Much less hassle, better results, more money.

Evaporust is nice, Just make sure not to let anything get above the 'water line'
Or you'll get a nasty line that won't come off. Also seems to slightly grey the metal.

BigJohnT
12-18-2012, 06:27 PM
My rust removal worked like a charm...

John

Andrew_D
12-18-2012, 07:55 PM
I don't even need to add anything to our water....well water that is. Water (and soil) pH's around here are commonly in the 8-8.5 range...

Andrew

Bluechips
12-18-2012, 08:56 PM
My rust removal worked like a charm...

John

Glad to hear you had success.

Mike

lakeside53
12-18-2012, 09:25 PM
Frankly, I haven't had a ot of luck with electrolytic. After reading this thread last week I decided to give it another go.
I'm cleaning a south bend Shaper. I used a 30-gallon plastic barrel, some lawnmower blades and plates for anodes, 6V manual charger for power.
I used 5 lbs of Soda Ash and about a cup of TSP. I left each batch overnight, the water was moving around, scum was coming up. I tried both 6V and 12V, both showing 4 amps or more.
I did the base, ram and cross-slide.
It loosened the paint, removed most of the rust, but still wasn't as clean as I wanted it.
So I soaked them in Evaporust and got the results I was looking for.

I'm going to order another 3 gallons of Evaporust to do the main housing.
Much less hassle, better results, more money.

With larger objects and your currents it might take several days, not overnight. I also use evaporust extensively, but as a finishing aid - knock off of the main rust, scale and paint with electrolysis, then evaporust to clean things up. The problem with using evaporust for everything is that you'll go broke ;)

I also use phosphoric on non-sensitive items (mixed metals etc) after electrolysis to passivate the surface and stop flash rusting.

Each of electrolysis, Evaporust and Phosphoric acid have their place in derusting, but one does not necessarily replace the other in all cases.

EVguru
12-19-2012, 05:22 AM
I also use phosphoric on non-sensitive items (mixed metals etc) after electrolysis to passivate the surface and stop flash rusting.

One tip for preventing flash rusting is to wash down with boiling water.

Rex
12-19-2012, 10:39 AM
My intention was to use electrolysis and follow with Evaporust as needed. But I am not willing to fuss with electrolysis to make it work well, when I can get guaranteed results with a lot less hassle right out of the jug.
As for the expense, I am paying $15/gallon for Evaporust at my workplace. I paid $100 for this shaper basket case, so I don't mind spending another $45 to de-rust it.
BTW anyone in the Fort Worth area can probably buy it for that price too, or very close to it. email me if you are local.

When I figure in the time and hassle of setting up the electrolytic, cleaning the anodes etc, not to mention the skeptical looks from the spouse as I assure her that bubbling barrel of scum-covered liquid will neither explode nor poison the wildlife....

Rosco-P
12-19-2012, 10:59 AM
It's been said before, no cleaning of electrodes when you use graphite. Consumption of the graphite electrode is negligible. No contamination of the bath with red scum either. Secondary benefit the current draw and "cleaning" action is constant and uniform. Not so when use scrap steel.

Rex
12-19-2012, 11:07 AM
Duly noted. If I happen across some graphite I may give it another shot.
But right now I've lost motivation.

lakeside53
12-19-2012, 12:58 PM
One tip for preventing flash rusting is to wash down with boiling water.

Yes. I do that with small objects, but no so easy with 150lb (or much larger) of cast iron!