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Military rifle re-finishing Q&A

Intro / synopsis: Hot bluing is more satisfactory than cold bluing but involves very dangerous boiling-hot solutions of concentrated caustic soda which have maimed and killed. The process requires careful design & operation, and operators require full PPE.

Q. Hello folks,

I am currently undertaking a few small projects involving refinishing stocks on ex-mill rifles, mausers and smle's. As an ex cabinet maker I am familiar with timber finishes, stripping etc. I have been asked if I would try re-bluing barreled actions and parts. My previous efforts have worked out ok using kits, and I understand that the job is only as good as the prep work.

I would really like to do justice to these old pieces and would appreciate any advice on:

a) cold bluing

b) hot bluing (caustic based ?)

c) rust bluing

Clint Thompson
- Nilma, Victoria, Australia
2001

Bead Blaster

on eBay or

Amazon

(affil links)

A. Clint,

I have been hot bluing for many years and prep work is a major factor. Extreme caution is most important as hot bluing is done with caustic solutions around 300 °F. You need an area that is exhausted as even the fumes can cause rusting of metal in the area. The solution will go thru leather, wool, skin, etc. so proper precautions are a must. Cold bluing [on eBay or Amazon] will work but is not as durable. I have found on some rifles that are parkerized, they need to be bead blasted to allow the bluing to work.

Ed Kay
- St.Louis, Missouri

A. Clint,

I forgot to mention if you go to a search program for gunsmiths or gunsmith supplies you will probably find a lot more info on bluing.

Good luck,

Ed Kay
- St. Louis, Missouri, USA

A. Hi Clint, and thanks Ed.
Indeed, people have been killed and others maimed when hot bluing tanks 'erupted' (a slug of water finding it's way into the bulk of the solution which is far above the boiling point of water, instantly flashing to steam, and blowing the hot solution onto an operator). Proper design and operation is essential -- but even then full personal protective equipment (PPE) is required including apron [on eBay or Amazon] , boots, gloves [on eBay or Amazon], and full face shield [on eBay or Amazon] rather than, or in addition to, goggles [on eBay or Amazon].

Luck & Regards,

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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