Hey oldred, Searching the web for "why phosphoric acid crystalizes in the vat?" I found you. I got a gallon of 85% phosphoric acid to clean old car parts. I loved the 1st valve spring i droped in, 4 hours later it looked new. I then soaked a sheet metal floor pan bracket in the same samall vat. I could not get back to it for 56 hours. When i did it had a white/gray crystal looking build up on it, (kinda like salt) & lots of that build up in the bottom of the vat.
What is that build up?
If i cut the acid with water will it stop the build up?
If I cut the acid, what percentage can i cut it too and it still be effective on rust? (I am not in my shed often enought to get it back to it quicker than 56 hours) I fugure it is too strong for my needs and i would love to stretch this stuff to save the $$.
I would like to know if you have any percent segestions?
And do i need to cut it with DISTILLED water or regular tap water?