Posted by KenW [99.65.177.89] on Tuesday, February 25, 2014 at 20:52:34 :
In Reply to: Re: Removing broken screws? posted by Sherman in Idaho [72.47.153.112] on Tuesday, February 25, 2014 at 19:06:30 :
If I recall the product was called "Tap Out". The kit contained nitric acid, neutralizer and some clay.
Once the acid is applied it starts bubbling indicating that it's working. Once the bubbling slows or stops, I wicked it out and applied more.
I have only used it with broken taps in aluminum, but it worked every time, just takes time. I never heated the acid, but that would accelerate the reaction. Heating nitric acid is not something I would venture into carelessly.
It goes without saying that when working with nitric, gloves, goggles, etc are important. Also be careful of the fumes.
Sounds like it would work on your brake light housings, but probably not on your castings, due to the iron content.
Good luck,
KenW