Rust in peace

[caprinut]

It really irks me to leave rust untreated and told that epoxy primer is the best a man can get, then be told you can't use acids or alkalies to treat rust because they react with the primer, phosphoric acid is the best in opinion because of it's high wetting ability, travels easily into crevices especially around spot welds that no primer can reach and has a self healing ability I've been thinking of using a chelating agent such as 'Evapo-rust' which I've heard epoxy it doesn't react with but I give it some skepticism since it's active ingredient is Phytic acid a little known agent and probably doesn't have a good wetting abilty as H3PO4 does Evapo-rust react with 2K epoxy primer?
Where modern cars are galvanized, rust has got into every conceivable crevice in my 40 year old car.

Bert

 

[ajlelectronics]

It really irks me to rust untreated and told that epoxy primer is the best a man can get, then be told you can't use acids or alkalies to treat rust because they react with the primer, phosphoric acid is the best in opinion because of it's high wetting ability, travels easily into crevices especially around spot welds.

The question is, how well do you want the job to be done? Epoxy is a superb primer and sealer, but it needs to be applied as the first coat. Apply anything else first and that medium becomes the weakest link. Remove the rust, don't just colour it black and believe that it will last.

 

[caprinut]

It goes black alright because it has become highly stable Ferric phosphate it resits mechanical removal. Other treatments which remove rust are water solvent and removed with water the enemy in a crevice.

 

[dave h 2]

Evapo-rust is ethanol based and should have no trouble wetting. I have no idea how many 5L @£50 you will need to sit a Capri? in up to the tops of it's sills.

As to "it has become highly stable Ferric phosphate it resits mechanical removal", we know it's called sales hype and it's fine till it gets wet again, then it goes kind of brown.

 

[ajlelectronics]

It goes black alright because it has become highly stable Ferric phosphate it resits mechanical removal. Other treatments which remove rust are water solvent and removed with water the enemy in a crevice.

Interested in a bridge for sale?

 

[caprinut]

Silver Bridge in West Virginia collapsed due in the most part to rust.

 

[caprinut]

I don't go for the hype, I prefer the chemistry if you have done it properly you sometimes see a white powder that is the acid crystals dried, you take the surface stuff of with scotchbrite where it's still in the rust / ferric phosphate it's hydroscopic turns acid again with the addition of moisture which is why it's self healing, it doesn't say that in the literature and then you give coat of encasulating primer preferably epoxy but not. The brown you see is where some idiot has attempted to wash it off you don't you let it dry in situ as it drys it become more concentrated and turns to crystals.

 

[caprinut]

Sometimes where the acid has pooled it goes brown all hydrogen ions have been used and rust rises to the surface take that off with blue paper and apply more acid.