I am boiling down "lye water" filtered through wood ashes in a
stainless steel pot. (MWC). Potassium Hydroxide in solution with
water
of 1.2 S.G. is what I seek.

No problem, I have done it many times before. Soap making is the
ultimate goal. (historical re-enactment)

My question is: Why does the pot on the stove bang, and want to
make louder bangs as it comes to a boil? I have to simmer the pot to
boil to avoid what seems ...kaboom


My guess is S.G. Specific Gravity...but sal****er heavy does not
bang
like this.

Yes, S.G. should be specific gravity. As for the banging, I think you
need some nucleation sites to get a nice smooth boil, with lots of small
bubbles forming in lots of places, instead of one giant bubble every so
often like you get now. Try adding a few small sharp pieces of gravel,
say 1/4" diameter. The sharp edges and pockets give nice surfaces for
bubbles to form at, which is why chemists call these "boiling stones"
:-). Broken unglazed ceramic chips or granite would probably be best.
Avoid marble in your lye solution as it will get eaten.

--
Regards,
Carl Ijames carl.ijames at verizon.net