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Bluing steel

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Bangkok Mick:
Has anyone had any experience bluing steel for aesthetic effect and anti-corrosion like a gun smith would do.

I produced a small steel model shotgun a while ago and am currently playing with a miniature crossbow (5” to 6” long) also of steel and am considering an appropriate but reasonable simple finish for it.

Any advice greatly appreciated.

Cheers Mick

Eugene:
Mick,

If by bluing you mean blacking (confusing terminology what?) you can do that in a couple of ways; hot caustic / nitrate / nitrite mixes available as "steel blacking salts" or rust bluing. The hot caustic method is simple and effective but you must have personal safety right in the front of your mind; 700 g/l caustic soda at 140 deg C isn't user friendly. The rusting process is a bit tedious and time consuming but safe, and gives a really nice finish when done right. There is also a cold bluing process that is available commercially (at some expense) but I've never used it so can't comment. The materials for rust bluing are easily obtained (well they are in Wales, not sure about Thailand!) from Brownells in the US and are cheap enough.

For bluing as in the colour blue, for small steel parts that are not critically hardened and tempered (springs, receivers and such) you can use the same stuff that clockmakers employ to blue clock hands. This gives a really nice bright blue to things like triggers. It isn't particularly hard wearing; I did the triggers on my SxS and they are looking tired after a couple of busy seasons, however it does make a really nice job on the heads of screws and pins that aren't subject to much wear. It's available commercially as in ...http://www.johnwardle.co.uk/250g-bluing-salts-15-p.asp A skilled man can do bright bluing with a gas torch, but I always muff it.

The standard work is "Firearm Bluing and Browning" by RH Angier published by Samworth. Somewhat old fashioned but very good and still in print.

Eug

chipenter:
For small parts of clocks I use a tin half full of sand , heated from below and droped in oil as soon as the right color is reached , or tinmans solder is the same temp as blue steel , oil blacking is a higher temp droped into the dirtyist
engine oil you can find and lasts longer than blueing .

stovebolt:
  Hi Mick,
  I do bluing/ black oxiding using the caustic soda/ sodium hydroxide / lye  solution.  It is very caustic.
  If you want to go that route you may be able to get a local drain cleaner with both of the main  ingredients,
  the first 2 ingredients on this MSDS are what you need the last 2 not needed and I've read that aluminium will actually kill the salts. 

http://www.summitbrands.com/summit/downloads/msds/usa/MSDS%20Drain%20Out%20Crystal.pdf 
 
 But if you are not in a hurry, there is a slow rust bluing process.

 Degrease the part,  let it rust, shouldn't be a problem in Thailand, you can speed up the process by suspending the part in a bucket with  some water in the bottom , cover and let set a day or two,   boil the part in plain water, then using 0000 steel wool  and oil gently polish.  repeat  the process  4 or 5 times  or
until you are satisfied. 

Here's another method  , reverse electrolytic rust removal

http://castboolits.gunloads.com/showthread.php?137610-New-take-on-quot-slow-quot-rust-bluing         

DavidA:
Stovebolt,

Re   I do bluing/ black oxiding using the caustic soda/ sodium hydroxide / lye  solution.

I'm not sure how to read that.

You do know that the three substances in that line of text are all synonyms for the same chemical ?

I.e NaOH.

Dave

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