Carbon Steel, Phosphoric Acid, and Plastics

[CptDondo]

Does anyone have any experience with applying phosphoric acid (Ospho, Rust-Mort, etc) to carbon steel that's got wiring attached to it?

I'm trying to figure out if phosphoric acid attacks common plastics like wiring insulation and water tubing. It can't be too bad as the acid is found in soft drinks, but certainly not in the concentrations used in Ospho...

[sailorboy1]

I doubt it would hurt plastics or the insulation on the wiring. I'm in water treatment and we feed straigft acid though plactic tube and pumps without problems. Phosphoric acid is a fairly weak acid, but it has to be flushed/neutrazied after using or it will eat though the metal (keep it away from alumimum). I would be more worried about he acid getting into the wiring under the insulation so would say it's a must to remove the wires while using it for cleaning and flushing. I used to build custom bicycles and used the auto paint type prep acid a lot for cleaning the tubes before painting. I would recommend something like this over the Home Depot type of phosphoric acid type cleaners.

[cal40john]

Compatibility chart, but I don't know off hand what wiring insulation is made of:

Cole-Parmer: Chemical Resistance Database

John

[CptDondo]

Thanks for the encouragement.

I can remove (loosen) a lot of the wiring, and I was planning to brush the stuff on (not spray or dunk). I can't remove the wiring entirely, so I expect some splatter will happen. I don't think there are any connections anywhere in the affected area - at least none that I can discover - so I don't expect the acid to get to the copper. If it does, I guess I'll spend some time with a soldering iron and heat shrink tubing replacing sections of wire loom....

[CptDondo]

From the database, the stuff attacks stainless (both 304 and 316) and copper severely, so it's best to be careful....

[sailorboy1]

I wouldn't worry that much about the stainless unless you leave it on and the stainless under goes stresses (lots of bending, heating up & down). But then the question was about carbon steel.

[CptDondo]

I was just playing with the database. Being an engineer I can't help playing with new toys. That's why I have so many. :-)