Electrolytic de-rusting - engine block ?

[Special Coupe Frank]

Has anyone tried electrolytic de-rusting of a Ford engine block ?

I assume doing so would not be good for any babbitt still in the block, but am also thinking it would help loosen / dissolve rust and scale in the water jackets ?

Thanks,

Frank

[silversink]

would work for the outside but to do the inside you would have to suspend the electrode in the inside without touching----would be hard to do. molasses would work on the inside or maybe vinegar would be a better choice.

[captndan]

Electrolysis works great but is line of sight only. Phosphoric acid would be better then lots of water. Even better take the block to a machine shop and have them 'boil' it out.

[ronn]

I used vinegar on my 12 Buick and it did wonders for my engine and rad.

left it in for 6 weeks and started it a few times to heat it up- then flushed it a few times and added antifreeze.
water looks good now and runs cool.

[Mitch//pa]

I use evaporust

[captndan]

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Originally Posted by forever4

Despite comments otherwise, electrolytic derusting is not line of sight. Plating operations are line of site, but not derusting. See the pages on my website. I use it a lot on all manner of cast iron and even gas tank. Don't believe it? Suit yourself, or find out for yourself.

I think the misunderstanding here is the word (derusting). Electrolysis does not derust anything. It does not remove rust. Electrolysis changes iron oxide (rust) to iron phosphate an inorganic and harmless material. Plating is adding something to something. Electrolysis is simply changing something that is already there. Sorry for the confusion.

[Pickupman]

Originally Posted by captndan

Electrolysis works great but is line of sight only. Phosphoric acid would be better then lots of water. Even better take the block to a machine shop and have them 'boil' it out.

Boiling out a Model A block is not going to remove the rust. Your just pissing your money away.

[Cool Hand Lurker]

Originally Posted by captndan

I think the misunderstanding here is the word (derusting). Electrolysis does not derust anything. It does not remove rust. Electrolysis changes iron oxide (rust) to iron phosphate an inorganic and harmless material. Plating is adding something to something. Electrolysis is simply changing something that is already there. Sorry for the confusion.

Well it sure looks like the rust is gone and clean metal is remaining.

I did a flathead V8 a couple of years ago and it did clean out the inside of the block. I put it into a 55 gal. plastic barrel with rebar poked down all around the inside of the barrel. I hooked up a charger to a battery and took the leads from the battery to the rebar (+) and to the block (--) and left it for about two weeks. The outside of the block looked like new iron. The inside needed more treatment to get all the rust deposits out but a lot of patches looked like new iron too.

I used Vince's carbon rod idea instead of rebar on the next project and it worked very well.

[Big hammer]

I haven't posted until now, when I tried electrolysis the line of sight rust removal was good, but the blind parts removal not so good. I only left the part in for a few hours, I was worried about loss of base metal. I then tried Evaporust, IMHO Evaporust is the way to go,it doesn't harm base metal doesn't harm other metals. So with a carburetor you could leave it together and derust it with out total disassembly. I have no association with Evaporust , I only wish I could have a barrel of it to do larger parts, like a engine block!

[Special Coupe Frank]

One of the attractions to the electrolysis method ( for me ) is the relatively low cost involved.

If I were going to do a whole engine block, I would find a plastic trash-can just big enough to stand the engine in, on-end, then do the water / washing-soda, etc.

Perhaps I'll use a cylinder head as a guinea-pig.

Ultimately, I don't mind letting the thing "cook" for a day or so, so long as it does the trick.

Thanks to all for the replies...

Frank

[Jon-Ohio]

Back in the early 80's, I took the head and stripped down bare block to a Redi Strip location in Columbus Ohio and had them de-rusted (Electrolytic) and clean the block and head. It left the block and head very rust free inside and out. They phosphated them to protect from rust till painting. It did damage the old babbit which didn't matter since it was going to an engine rebuilder and would get new babbit bearings in the rebuild. I think it cost me about a $100 at that time more or less (early 80's).

Jon in Ohio
1930 Coupe