Navel Jelly Help

[mrblue]

So i used some navel jelly on a rusty mold and it did a decent job of getting rid of the rust. How ever after i removed it and gave it a hot water bath, it has seemed to leave a white film on parts of the mold. IT also seems hard to remove with a nylon brush. Any ideas what it is and how to get ride of it or prevent it?

[BK7saum]

IIRC naval jelly is phosphoric acid. Any chance the white film is the same/similar to a parkerizing of the metal. If so you probably won't be able to remove it. I don't think it will affect mold function.

I would heat it up and see if heat/oxidation changes the color and appearance of your "film".

Also the mold is now "in the white" and there is no oxidation or other protective layer to the mold surface.

[Old Caster]

My guess is that you let it dry on the metal. Phosphoric acid has to be wiped off while it is wet. When used on the sheet metal of a car before painting, all that is necessary is to wipe before applying primer and if you leave it dry the white film will form. I never used water to get it all off because that wasn't necessary but a mold has such sharp edges, I doubt just wiping will do it and maybe water and an immediate squirt with air to dry it might work. Possibly high pressure air might do it without the water but be careful not to spray the wet acid on everything including yourself.

[Gtek]

I have used OSPHO- Phosphoric acid for many years. Used it on molds that I have picked up over the years. Yes, you do not let it dry on piece, you must remove excess before it dries. On the molds I clean/scrub with bronze brush, will take to "in the white" compressed air blow dry. Then bronze brush and cold blue, fire up the pot and away you go. Gtek

[Dale in Louisiana]

'Navel jelly'? Is that kind of like 'toe jam'?

dale in Louisiana
(stuck in a hotel room far from home, with too much time on his hands)