electrolysis rust removal question
Thread Starter
Drifting
Joined: May 2000
Posts: 1,952
Likes: 6
From: Palos Verdes Peninsula California
electrolysis rust removal question
For those who have used this, what does the metal look like after the rust is removed?
The reason why I ask is that I have seen videos where the metal from the part which had the rust removed was black afterwards, and another where it was regular gray/silver metal color.
The reason why I ask is that I have seen videos where the metal from the part which had the rust removed was black afterwards, and another where it was regular gray/silver metal color.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
I've experimented a little and everything has been black so far. Most have said the black can be removed.
Dupont sells a can of spray rust restore that says it leaves a black paint-able coating of black oxide. I wonder if whats left from the electrolysis process is the same as the Dupont spray (which is acid) ?
Dupont sells a can of spray rust restore that says it leaves a black paint-able coating of black oxide. I wonder if whats left from the electrolysis process is the same as the Dupont spray (which is acid) ?
Le Mans Master
Joined: Jul 2006
Posts: 8,117
Likes: 104
From: charlotte north carolina
a little off the topic. i've used the rust removal chemicals(not acids) on small items. the name "rust doctor" comes to mind. the stuff works very well and won't damage plastic or rubber. i think harbor freight sells something like it.
Burning Brakes
Joined: Dec 2010
Posts: 945
Likes: 10
From: Winston Salem NC
Harbor Freight sells Evaoprust and it works well. I was surprised the first time I saw it work. I used them on my seat latch parts. After a day they came out pure and silver:
Before:
After:
Evaoprust leaves a coating that can be rinsed off with soap and water. I would dry my parts immediately with pressureized air and then prime/paint.
I love that stuff. What is simpler than dunking a part and then rising?
Before:
After:
Evaoprust leaves a coating that can be rinsed off with soap and water. I would dry my parts immediately with pressureized air and then prime/paint.
I love that stuff. What is simpler than dunking a part and then rising?
Instructor
Joined: Mar 2010
Posts: 228
Likes: 0
From: Evansville WI
Right out of the bucket, it'll have a black film on it. The film easily rinses off with some water and a scub brush leaving the bare metal.
And Evap-o-rust works great too, it's one of my favorite products
And Evap-o-rust works great too, it's one of my favorite products
Last edited by Bugman Jeff; Aug 29, 2011 at 10:53 PM.
Instructor
Joined: Mar 2010
Posts: 228
Likes: 0
From: Evansville WI
I don't think so. The black left by the spray on stuff is Iron Phosphate fromed from the reaction between the iron and the phosphoric acid in the conversion coating. I used to know what the black coating electrolysis is, but it's since slipped my mind. I want to say it's also iron phosphate, but I don't know where the phosphorus for the reaction would come from.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Almost all those products contain phosphoric acld and ethyline glycol, to varying concentrations, including Evaporust.
The Dupont 5717s and 225s have lower concentrations as well.
Dupont 226s has hydroflouric acid and worst well for aluminum.
Evaporust just has such lower concentrations that it doesn't have to qualify it as an acid. Also why it takes longer.
If you rinse any of them off when wet, you will have bare metal.
If you let the black coating dry on, it becomes the phosphate protective costing. AKA cold black oxide.
Black Oxide is the better process using hot a alkaline salt solution usually for bolts etc.
In all cases, if you remove the black coating, you have removed the rust protectant.
The Dupont 5717s and 225s have lower concentrations as well.
Dupont 226s has hydroflouric acid and worst well for aluminum.
Evaporust just has such lower concentrations that it doesn't have to qualify it as an acid. Also why it takes longer.
If you rinse any of them off when wet, you will have bare metal.
If you let the black coating dry on, it becomes the phosphate protective costing. AKA cold black oxide.
Black Oxide is the better process using hot a alkaline salt solution usually for bolts etc.
In all cases, if you remove the black coating, you have removed the rust protectant.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
You can make your own tank with a 55 gallon plastic drum, battery charger, copper coated ground rods and anodes.... toss in some sodium hydroxide as a cleaner and sodium carbonate for an electrolyte... and your all set!
Last edited by Willcox Corvette; Aug 30, 2011 at 10:06 AM.
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