15 years ago
tarnished brass (in my case they are tubes for a carburetor, turned
near black from a rough life I guess). Among the suggestions was
ammonia and H2O, and vinegar and salt, ketchup, and a 2% nitric and
H2O mix. In the shop the only thing I have from the above list is
nitric, so I tried it.
I heated the water in a kettle, then poured it in a glass cup... added
a splash of nitric and dropped in the brass tubes. It fizzled a bit,
then after about 10 minutes or so, it was done the fizz. I added
another splash of Nitric and bingo, that second bit really, really
cranked up the results. These parts came out looking brand new... an
outstanding before/after difference. I would estimate the first bit
was at 3%, the second was at 7% or so... give or take..
This led me to a few questions. It seems the Nitric lost its punch
after soaking the part in there for a bit? I am no chemist, so this
may seem obvious to those in the know. Does a chemical reaction cause
it to weaker as it gets working on cleaning the brass.
Because Nitric is kind of a pain in the butt to get, I was kind of
hoping that I could have a little container of it that I could keep
and just use it as I have parts to restore, then cap it off for the
next time.... but from my experience today, I will have to neutralize
and discard the batch after each round.
Any useful, positive info is very much appreciated!