Bluing

[ph3s]

I need some help gents, what would you recommender for bluing. The point is all this gun-blue liquids or gels are fine for non tempted metal. I need to re-blue a bayonet. On hardened parts it's simply turning blue, I mean nasty blue-violet

Help please

[Glenn66]

I remember my dad telling years ago to heat the metal up with an oxy torch and dunk it in oil to quench it.

[Nige H]

You've a couple of options really, ether a hot or cold chemical bluing process, these involve ether aids of alkyds which react with the steels substright and cause a blue or black oxide to form. for a cold bluing paste I would recommend G96 this is very good, just ask Ade LOL. For hot bluing I would recommend using caustic bluing or blacking salts depending on the finish required, but be aware G96 is poisonous and caustic salts can cause very burns and steam explosions if the safety information is not followed. Heat bluing with a torch or blow lamp is O. K. but can come out very patchy also hot oil (oil finishing) can have the same problems also if the steels to hot when plunged into the oil, you can cause the black oil oxide to fake off from the surface, as it does not adhere to the steel correctly.

Nige.