Would like to just blue the handle and leave the remainder bright. I've been told that the entire bolt must be blued and polished back.....seems like alot of unnecessary work. Can the portion not receiving blue be masked off to save the polishing efforts?

Blueing is done at a temperature of 285-310 degrees. Can't think of anything that would stay on.

Several layers of plain ol' masking tape works for me. Keeps 99% of the solution off of most bolts. Kind of messey taking it back off though. Bill

Yes it is easy to do. wrap the part you do not want blued tightly with about 10 wraps of masking tape & use iron wire to hang the bolt from making the wire long enough to use as a handle & stand the bolt on end in the tank using the wire as a handle to pull it out & check for depth of the bluring. Piece of cake!
I've used this method more times than i can count.

Wow!
Thats hard to believe.

Does anyone have pictures of what masking tape looks like after it has been sitting in a 285 degree caustic salt bath for 40 minutes?

Needless to say I am a bit skeptical.

-Spencer

well itz worked for the last 30+ years. Only submerge the part you want blued.

I know that Doug would post it if it did not work. I just rust blue and I put on a coating of black lacquer and two wraps of masking tape.

Just blue the whole bolt and use "Naval Jelly" to remove the blueing where you don't want it.

"Navel Jelly" is a rust remover and as such will remove blueing.

Be careful as this stuff works almost instantainiously!

Jim Dubell got me started using electrical tape mask off bolts for caustic bluing. Stays on better than masking tape. Still messy coming off but better than having to repolish after bluing.

Wow learn something new everyday. Lost count of how I had gone back and polished. I thougth I was way ahead when I started hanging them over the tank.

Electrical tape, works great.