Phosphoric acid- How long can I soak?

[Pookster]

and no, I dont mean myself..

I decided to try it with my rusty exhaust bolts. They came off, but they were a bit crusty. the threads dont look bad.

I put them into a container, and poured navel jelly on top. I let it sit for 15 min, didnt seem to do that much. No bubbles, no nothing.

So I let it sit overnight. Seemed to be more effective, but dried out a bit. So I added some water.

Here is my question: I looked online, people dont seem to have anything bad to say about it- as navel jelly does not have HCL in it (rustolium brand has HCL and phosphoric acid).

One site said that soaking steel in HCL will make steel brittle, but doesnt happen with phosphoric.

The bolts are now almost totally black- so I think I will remove em from the bath today. Since I put the stuff in a tupperware, Im just going to store the solution and use it for the next batch of rusty bolts, unless someone tells me that it weakens the metal.

 

[Chaddy]

Why don't you get new bolts?

 

[Pookster]

I have a box of grade 8 bolts and nuts. Just an experiment thats all. I've worked on some stuff that have like a special bolt of some sort, so Im just testing this process.

 

[Chaddy]

Ahhh, I see. Just dont put the test bolts in to be safe.

 

[4X4HIGH]

Muriatic acid will remove rust in a big hurry. It is commonly used for cleaning pools so should be real easy to get.

 

[Pookster]

Muriatic acid will remove rust in a big hurry. It is commonly used for cleaning pools so should be real easy to get.

woah, thats different stuff, thats HCL- that will eat metal. Phophoric acid is supposed to only attack the rust... heck, its in my soda.

Chaddy why do you say, not to use it? Im thinking if the acid only eats the rust and converts it from iron oxide (aka, rust converter), it shouldnt be able to convert the iron..

Anyways, Its only exhaust flange bolts. Worse comes to worse, they snap, and i put in new ones.

 

[redneckdude]

woah, thats different stuff, thats HCL- that will eat metal. Phophoric acid is supposed to only attack the rust... heck, its in my soda.

Chaddy why do you say, not to use it? Im thinking if the acid only eats the rust and converts it from iron oxide (aka, rust converter), it shouldnt be able to convert the iron..

Anyways, Its only exhaust flange bolts. Worse comes to worse, they snap, and i put in new ones.

ive used hcl/mauratic acid on metal before, as have MANY other guys that ive talked to that restore vehicles, etc, and it seems to work. I would'nt leave it in there for a prolonged time, but 5-10 mins takes care of most ALL rust...

side effects, im unsure of, but i know its worked for me and others before.

 

[Ned Kelly]

You can buy mauratic acid at Home Depot and other hardware stores. Also body shop paint supply stores.