Coating For Mild Steel

Ed ke6bnl said:
How exactly do you phosphate coat let say a .5 bolt by 4 in. verses just oil and bake
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I dilute some of the phosphoric acid I buy at the farm store about 5:1 and just soak the bolt in it overnight. If you heat the solution to near boiling it takes about 15 minutes.
 
John Hasler said:
I dilute some of the phosphoric acid I buy at the farm store about 5:1 and just soak the bolt in it overnight. If you heat the solution to near boiling it takes about 15 minutes.
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Thanks, I will be trying that, I believe big box stores have phosphoric solutions
 
John Hasler said:
I dilute some of the phosphoric acid I buy at the farm store about 5:1 and just soak the bolt in it overnight. If you heat the solution to near boiling it takes about 15 minutes.
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Very interesting subject. What is the brand name of what you use? Any detailed procedure that you use?
 
kingmt01 said:
Very interesting subject. What is the brand name of what you use? Any detailed procedure that you use?
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I buy whatever brand of phosphoric acid-based pipeline cleaner the farm store stocks. The procedure as described: I'm just after a protective coating, not a firearm-quality finish. You do need to remove all oil. If the parts are rusty it helps to scrub them a couple of times during the soak with a stiff plastic brush. After the acid treatment I rinse with tap water and air dry. I often then apply boiled linseed or or tung oil to tools and then bake them for an hour at 250F.
 
Thanks. I've never used phosphoric acid. The name brand is so I know what I'm looking for. It seems I've heard of this before. I'm not sure of the word but here is a shot at it. Is Parkanising or something similar to that word the correct term for it?
 
kingmt01 said:
Thanks. I've never used phosphoric acid. The name brand is so I know what I'm looking for. It seems I've heard of this before. I'm not sure of the word but here is a shot at it. Is Parkanising or something similar to that word the correct term for it?
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Parkerizing uses phosphoric acid, but there's a bit more to it if you want the full effect.

I just emptied a jug of "Sterosol Milkstone Remover and Acid Rinse".
 
I thought it sounded like something I'd read before. I couldn't remember exactly what it was tho. Good information that I may have to research again.

Where I live you can actually watch the rust grow. I've just come to accept it as another coating in itself. I've pulled parts out of acid to paint & before I can get the water wiped off to spray them they are already rusting again.
 
kingmt01 said:
I thought it sounded like something I'd read before. I couldn't remember exactly what it was tho. Good information that I may have to research again.

Where I live you can actually watch the rust grow. I've just come to accept it as another coating in itself. I've pulled parts out of acid to paint & before I can get the water wiped off to spray them they are already rusting again.
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Nothing encourages rust like HCl (muriatic acid). Phosphoric provides a pretty good base for paint and discourages rust.
 
I add manganese dioxide to my phosphoric acid. Therefore I get something akin to KemPlate from the old days. Big Red spec'd it, as did most of the oilfield service companies.
 
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