Rust removal

hotcoupe

hotcoupe

Well-known member
I needed to remove the rust from an engine crankcase and other assorted parts. I wanted to do this effectively, without damage and it had to be cost effective. I have used Evap-o-rust with excellent results, but the price of the product has gotten out of hand. After a conversation with a friend who is a chemical engineer and searching online for information I decided to give it try. The materials involved are distilled water, tetrasodium EDTA (I believe this is a food preservative), citric acid, and you will need some PH test strips. I mixed 25 gallons of the solution and it cost me about $135.00, here are some before images.
Tom
 

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And a few more images.
 

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Looks like a Mercury block circa 1941 or 1942. What's the reason for the extra gallon containers in the tub? Looking forward to seeing the results.
 
Gary, results are posted, the block has to be completely submerged and I had to displace an additional two gallons in the container I used.
Tom
 
Hey "hot coupe", fantastic effort!
Please post an accurate recipe, as well as test strip use, etc.
All of us Barners need this important info.
Evaporust is a wonderful product but is WAY too expensive IMHO.
Those that have investments in Evaporust stock should off load ASAP!
 
I have tried citric acid before, but have not had very good results. From these pictures, I must be doing something wrong. I know I only used the citric acid powder with no other ingredients. I have no knowledge of "tetrasodium EDTA"; perhaps that was my problem. Would it be possible for you to supply more details about the mixture? Proportions and ingredients, that sort of thing. I still have most of a bag of citric acid under the bench, and should probably try again.

We should remember that vinegar, citric acid, and even molasses are acids and therefore must be carefully watched or they can go to far and damage the base metal. There was a thread on the H.A.M.B. several years ago from a poster who left a block in a molasses solution too long and ruined it. Cost is a consideration, but Evaporust and it's clones work by a different process (chelation) and will not harm the base metal. I'm not selling my Evaporust stock (even if I had any) soon.
 
I plan on doing the same to what I think is a good 8BA block before I take it to the machinist. I picked up some esprit and plan on giving it a try along with a tank heater. Need a couple days of good weather before I try it. It’s either too cold or too rainy.

JB
 
hot coupe,
Sure looks good from here! Electrolsis is good process but will not work well on the inside passages.
Regards,
Chris
 
Electrolsis is good process but will not work well on the inside passages.
This is a chemical reaction known as "chelation", not "electrolysis". It is as effective on the interior water passages as it is on the outer surfaces. And this process, used correctly, will not harm the parent metal. I will post all the details in a day or two.
Tom
 
Why not have it baked, degreased and shot peened at a machine shop? You'll have to have the machine work completed as well. Unless you're doing all the machine work yourself, I could understand.
 
Seth Swoboda said:
Why not have it baked, degreased and shot peened at a machine shop? You'll have to have the machine work completed as well. Unless you're doing all the machine work yourself, I could understand.
Click to expand...

In my case at least, I had acquired an engine that ran great and had good compression and oil pressure. I didn't think tearing it down and rebuilding it made sense. I did however, want it to run cool, thus the Evaporust treatment. The results were worth it, as I am still running that engine after 6 years of service. They way things are, that engine will outlast me, so I think it was the right decision.
 
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