Caustic blueing, NaOH any good? other fittings finishes?

S

stezann

Joined
Apr 13, 2011
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Hi guys,
being experimenting fittings finishes for a while... i don't have available stainless 416 for guards, so i was using mild steel, which in the end is too prone to rust issues to my likings, if left as is (i am also tired from using brass and i have not available anymore nickel silver!!).
I had nice results with heat coloring to the blue and gray oxides hues, and now i would like to try the shine-black finish of the caustic blueing.
Is it possible to use a simple hot (which temperature?) NaOH solution and get good results? Or is it mandatory to get professional blueing salts?
Has someone some recepit which works to suggest, using simple materials readily available?
Also any pics of the final results would be very welcome.

By the way, i heard that many, when heat coloring, quench the piece into oil...does the oil "fix" the oxides anyhow?

Thank you for the help :)

Stefano
 
Hey Stefano,

I use Christie's gun blue that I get from Smith gun works.

It is the best Ive used.

I have made my own from easily obtained hardware store chemicals, I found that it works well.

Both work at temps from 285°f to 315°f.

Greg
 
thank you very much for your kind reply, Greg.
From browsing the internet it seems that the nitrate ingredient plays an important role together with the caustic agent.
Another question regarding the working temperature: do i need a heat source or does the reaction itself provide the necessary heat?
on the way around, should i cool somehow the solution to stay in the range?

thanks

Stefano
 
Stezann,
Caustic bluing ( hot bluing) and other similar processes are not for home experimentation, which is one reason I and others rarely give answers to questions about them on the internet. The last thing I would ever want is some 14 year old thinking , "Oh, I'll just heat some Drano up in the microwave and drop my guard in it....it is easy, I read it on Bladeforums or saw it on YouTube". This could end with disaster.

The solutions are heated to above the boiling point of water and are both toxic and corrosive. They must have closely controlled heat and proper material for the tanks or bad things can happen. There is more than one tank involved in the process, too. All sorts of safety procedures must be rigidly followed if you don't want to end up looking like the villain from a comic books called "Scarface".

Most any good gun shop will hot blue a small part for very low cost. Have the piece completely sanded and polished before you take it to them. They will tell you any other requirements.
 
Ok let's say i'm 38 years old, have a laurea in science...and my greatest wish in life is to look like the villain Scarface ;)
Just kidding, i was looking for first hand guidance expecially for the heat control, but if you prefer not to disclose to the public informations which you consider capable to put someone who read in danger, it is ok with me. :)
Unfortunatly in my area there are no gun shops whom ask the courtesy :(
I will give it a second thought... but probably i'll first try the sweatbox rusting & magnetite conversion method, which is less dangerous if you know how to handle acids.
Thank you Stacy

Stefano
 
Stefano,

I use a propane burner as a heat source.

Temp is controlled by raising or lowering water/chemical content which will raise or lower boiling point.

Stacy is correct, this can be a dangerous process. You need to take every safety precaution!

What you have is boiling vat of acid, be VERY CAREFUL PLEASE.

Greg
 
Thank You Greg, i will be super careful,
resuming, for the bath management:
- add slowly the chemicals to the water
- start the burner
- measure the temperature at the boiling point
- to lower the temperature: add carefully more water
- to boost the temperature: add a little more chemicals to raise the boiling point temperature.
- if possible by any means: avoid the entire procedure and get some 416 steel for the fittings ;)
thank you

Stefano
 
If you decide to do this, please research the whole process well. If at all possible read a book on the process, as the internet can have bad info. Karl Anderson would be good source, and I would email him with full details of how you plane on doing this.

Using commercial chemicals/equipment and a process designed for them is far safer than home brew chemicals. Many companies that sell gunsmith supplies ( like Brownell's) sell the equipment and chemicals as well as books on the subject. Most tanks use a long burner pipe under the entire length of the tank to heat it evenly. On a smaller tank, a round burner like a gas stove has works fine. Avoid a single flame burner. The burner need fine control to regulate the heat.

Most folks doing this type process wear a full length rubber apron, rubber elbow high gloves, and a full coverage face shield.

Have plenty of the neutralizer close at hand as well as a flood source of water ( Wash down shower, or at the minimum a hose with a "flood" head).
 
Thank You guys!!
That is exactly the feedback i was after when i posted on bladeforums.com
I know there are dangers correlate to that kind of procedure and i was not confortable to go my own simply after browsing some internet pages.
thank You again for Your kind support and for making me feel part of this community.
I will revert on this page when i'll manage to get all the necessary materials for checking up with You before doing damages ;)

In the meanwhile i would be very happy to see this thread going on with pictures associated to brief descriptions of the bluing techniques used for the pieces.

cheers

Stefano

p.s. Karl Andersen's knives are top of the notch!!! all the bluing thing in my head it's from seeing it's works!!! ;)
 
Stefano,

Adding water to bluing salts at the boiling temp of 300°f is one of the things that make this a dangerous process.

Your water will turn to steam violently.

I add water before I start heating the chemicals. As the water boils off the temp will rise to the proper range then you can blue your part.

Although caustic blue can be dangerous I don't find it any more so than having a forge running at 2300°f in my shop.

You must be careful, but if you educate yourself on process it opens up another avenue in the wonderful world of knife making.

Greg
 
2 things - you have to add H2O to maintain the boiling temp as the specific gravity increases.
There is no alternative when using traditional salts.

If the violence of adding water to 300 degree boiling salts is dangerous, then don't add water.

Add ice cubes. ;) (It's a solid and won't instantly vaporize.) And by the way - that's a secret.

G. Shahan said:
Stefano,

Adding water to bluing salts at the boiling temp of 300°f is one of the things that make this a dangerous process.

Your water will turn to steam violently.

I add water before I start heating the chemicals. As the water boils off the temp will rise to the proper range then you can blue your part.

Although caustic blue can be dangerous I don't find it any more so than having a forge running at 2300°f in my shop.

You must be careful, but if you educate yourself on process it opens up another avenue in the wonderful world of knife making.

Greg
Click to expand...
 
I do a lot of gun bluing. All my chemicals and information comes from Brownells. The stuff costs money, but the info is free. Since the salts are caustic, have a bottle of vinegar available for nuetralizing if you get any on you. Please study the "how to" from Brownells. It also gives tips and methods that will be invaluable if you decide to do this.
Once I got set up, I have gotten a lot of business from gun owners. A good blueing job makes customers happy. A poor one is worse than not doing anything. Preparation is key. If you want one of the "mile deep" blueing finishes, you will spend much more time on the polishing than the actual blueing.
If you would like more info, email me at: kunklec@aol.com.
Chip Kunkle
 
thank you very much guys, for the precious suggestions!
Mr. Andersen, i watched with interest your videos, is the guard in your beautiful w2 ironwood bowie blued by this process? Very very nice!!!
I will setup an outdoor mini bluing rig to start approaching the materials behaviour; by the way, i think i won't need a larger vessel because i'm going to blue only guards/spacers/pommels, one knife at time (long time in beetween sadly, since it is not my job).
In your video on bluing i see you are cooking for half an hour, is it because you where deep etching a damascus blade or that much time is necessary as well just for bluing?

Mr Kunkle, thank for your kind offer, i'll surely chime when i'll have doubts...i appreciated a lot.

Cheers

Stefano
 
Like Chip said, the info from Brownell's is free.
Get their bluing manual and all your questions will be answered.

The time - 30 minutes - is the required time for the actual bluing process.
Prep time is much longer. Much.

Some of the effects you can get from bluing are very dramatic:













 
The American Gunsmith Institute puts out excellent videos

Slow Rust and Niter Bluing Course AGI 310
http://www.americangunsmith.com/app...ecret-Processes-of-Slow-Rust-and-Nitre-Bluing


Hot Caustic Bluing AGI 304
http://www.americangunsmith.com/app...ithing-Metal-Finishing-and-Hot-Caustic-Bluing

They are expensive, you may be able to borrow, or download or something.



Brownell's is an excellent source of chemicals for those in the USA

ITAR regulations make it miserable and expensive to get simple things from USA to Canada from there.
US State Department approval and an export license is needed even to get a scope or mounts.


Getting nitrate containing chemicals shipped to another country, damned near impossible
They are afraid of DIY bombmaking

I can't buy decent insecticide, or a bottle of stump remover crystals here because of the 911 changes (yet's it's all available in the USA - irony huh)


The bluing setups I've seen, are all done in separate outside sheds to keep the fumes and rust out of the proper shop.
 
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WOW!!
Thanks a lot guys!!
Karl, amazing finish on that stuff!!!!!!
I'm aware of the prep time, and i'm also very very slow...i can start a fresh green hardwood handle and by the time i'm finished i have a well seasoned one ;)
 
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