View Full Version : De-rusting tank

10-12-2004, 03:21 PM
If you've not yet set up your own derusting tank, you're missing out on one fine tool. All it takes is a container (bucket-drum-tub-pool!)big enough to immerse whatever part you want to cleanse the rust from, and a battery charger. Then fill your container with regular old tap water and add a teaspoon of Washing Soda for each gallon of water. Find an old stainless hub cap or trim piece and hook the positive lead of the charger to it. Let it sink to the bottom of the container. Then suspend the rusty part (Steel or cast iron stuff ONLY!) in the solution so that it doesn't short out against the piece of stainless you sank in the container first. Now hook the negative lead of the charger to the rusty piece and leave it be for awhile. Hours - days maybe if it's HEAVILY rusted.
After a time though, pull up the rusty part and rub at the rust with a finger. It should rub off pretty easily. In fact, this treatment will float most old paint off too! Pretty slick. Once it's softened the rust enough, remove the part and use , brushes or scouring pads to easily brush off the softened (kinda gummy actualy) rust. Be sure to either paint the part or treat it with etch or oil to keep it from hazing over with oxide again.[}:)]
I'm using a 50-gallon drum to do my rusty stuff. Man, you can do all sorts of things in that big of a container. Of course, the biger the part, the longer it takes a given amperage battery charger to do the job.;)
Also, while the solution may (will) get grimy after some use, it doesn't affect the efficiency of it. No need to change it at all. Just add a bit of water from time to time to make up for evaporation. Look for Washing Soda in the detergent section of the grocery stores. It's an addative for laundry washing.[8)]

Miscreant at large.

10-12-2004, 08:40 PM
Thanks for reminding me that I have to get off my butt and get my setup going. I finally located a 35 gallon plastic bucket for the base. I'll bet that a fella could renew an engine block in one of those things if he had a big enough bucket! Whew, I remember a couple blocks with stuck pistons and rusty cylinder walls that would have needed to be in there for weeks! :) I know a head will fit my tank, and that's really about the biggest piece of rusty metal that I wanna wrestle with. The deal with those cleaners is that they're "line-of-sight", correct? How would a fella get the "hidden" pockets clean, like inside the block, intake and exhaust ports, etc.?


Mike N.
10-14-2004, 05:38 PM
To reach those hidden pockets you just need a smaller electrode with a plastic mesh over it, drop it in the area you want to clean being careful the mesh stays completely over the electrode. The mesh prevents the metal electrode from touching the metal you're cleaning but allows the process to work through the holes in the mesh. I did an intake manifold with it that way.
On a side note, I need to try the teaspoon per gallon ratio for the washing soda, I had a lot more than that in there!

10-14-2004, 08:17 PM
Thanks Mike, I should have thought about that, duh..... I'm getting ready for winter here, (already), and preparing a place for my de-rusting setup is a prioity. Hell, I have about 8 or 9 months to perfect my technique. :)


10-19-2004, 02:31 PM
Lately, I've been doing exhaust manifolds and cams. I can't believe how nice these rusty old cams have come out after sitting out in the WEATHER even for years! I've got 5 or 6 so far that are gonna go to Ted Harbit eventually. Cores for him to grind hot cams from!
My 50-gallon tank won't quite swallow a V8 block - but I'm looking for a tub or something that will. In fact, maybe an old metal or porcelain tub would do with bricks or wood blocks or something non-conductive for the engine block to rest on. I have a full-flo block that had all the machine work done to it and then was left in a basement for years. It's got a nice, even coat of surface rust all over it. I'm thinking of knocking the new cam bearings out of it and giving it a sits bath in the derusto solution. Then it should be good to go.
On my 50 gallon drum, I've got a metal bar that rests atop the drum with a couple of hooks that reach down low enough to be into the solution a bit. The parts being cleaned hang from the hooks. The negative lead of the charger's clipped to the bar. I pull out the recently treated pieces - see if they need to stay longer or they're ready for a brush and rinse - then either reimmerse them or hang the next rusty candidates and let 'em fizzle away. In fact - I need to go out right now and check on the stuff I put in yesterday.

Miscreant at large.

10-19-2004, 07:13 PM
Awesome! You've got me MOTIVATED Bob! I have a chitt-load of rusty parts that should be in the tank. In fact, what a deal for a fella like me who's snowed in his garage like a rat for 8 or 9 months. I'm gonna start a little smaller than what you have going there, I have a 35 gallon tank, but I really like the "bar with stuff hanging on it" idea. That means the cable clamp from the battery charger won't be in the soup and dissolve eventually. Heck, if it works as good as it sounds, I'll buy a dedicated battery charger. How "big", (amps wise), is the charger you're using? An engine block would probably take a LOT of current. Also, can it clean out water passages?


10-19-2004, 09:10 PM
Yeah, as yet I've not really used this 50 gallon thing to it's capacity. I just got a pair of stripped heads I might try next.
I'm usin' a charger that has a max of 10amps now. It rarely comes close to pegging when I have a load on it.
You CAN clean in some tight places (like water passages) if you use the insulated rod trick that Mike mentioned. Just get a rod to serve as the anode, insulate it partially with close-fitting plastic tubing with notches cut every inch or so and then slide the plastic bushed rod into the water passageways in such a way that the exposed parts of the rod don't tuoch the block. Then just let'r soak and fizzle a good bit. A good strong hosing out should flush the loosened crud out!

Miscreant at large.

Mike N.
10-25-2004, 09:08 AM
Something I recently found out was that a local place that dips entire car bodies uses a similar system as this. I was picking the guys brain and he said they actually reverse the current back and forth to give it a "push and pull" effect. I also noticed they were carrying a large tank on a fork lift and it was steaming so they must be using heat also. Anyone know of a good way to switch polarity of the current back and forth?

10-25-2004, 07:32 PM
Go to Radio Shack and get a double pole, double throw center off switch. Ask them how to wire it as you want, it's easy. With center off, you can turn it off, too.

Tom Bredehoft
'53 Commander Coupe
'60 Lark VI

12-14-2004, 02:47 PM
Hey, this is a great topic. Like manna from heaven...

Is there a website that explains this process/technique? I understand what's happening here thru electrolitic action, but I don't remember talking about removing rust in any of my science classes, just basic plating...if that...just as an experiment...

Thanks for a new way to look at my garage work.

'54 Studebaker Commander Conestoga wagon 'junkyard rescue gonna-be hotrod'
'54 Studebaker Champion Conestoga wagon 'all original thanks to the Commander'

Wheels down, shiney side up, drive it like you stole it!

Henry Votel
12-14-2004, 02:59 PM
Google "electrolysis rust" and you'll get an armload of pages discussing how to make your own.

I push something through my tank about once a week; sometimes more often. Sure beats hand cleaning and wire brushing.

Henry Votel
Forest Lake, MN