hot bluing

marekz

marekz

Joined
Jun 16, 2008
Messages
1,699
can someone please explain hot bluing to me. why its done, what are it benefits, and how its done.--thanks mark
 
Heat your blade in the microwave for 20 minutes...sorry, couldn't resist. I'm interested too. From what I've read it's much more robust and corrosion resistant than cold blue, etc. I know you have a special setup for it (guessing a heating tank, etc.) but I'm curious what all goes into it.
 
My dad and I have been doing it to my O1 blades. It is pretty tough and prevents rust on the blade. All bluing is is a type of controlled oxidation on the surface of the steel.

Basically, we use a mixture of lye and potassium nitrate (Grants Stump Remover) mixed with water and heated to around 280f. The lye raises the boiling point of the water and allows you to get to the required temp.

You have to be careful and don't let aluminum anywhere the solution. It will disolve it on contact.

Here's more information on how to do it. I think the solution they use is different but the result is essentially the same.

http://www.rugerforum.com/phpBB/viewtopic.php?p=116322&sid=5b9fa94ee7c1c7cf732dfd378daf415c#116322

Hope this helps.
Patrick
 
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you first have to get bluing salts. you then add this salt to water until the boiling point is raised to about 275 degrees f. clean and dergrease the blade and put it into the hot solution for a time to acheive the depth of color that you want. HOWEVER, this stuff is VERY caustic and nasty to work with the vapor that comes off of the hot liquid can condense on your skin if it is not protected. it can also get in your lungs without proper protection where it will cause caustic burns so be careful
 
Patrick T said:
My dad and I have been doing it to my O1 blades. It is pretty tough and prevents rust on the blade. All bluing is is a type of controlled oxidation on the surface of the steel.

Basically, we use a mixture of lye and potassium nitrate (Grants Stump Remover) mixed with water and heated to around 280f. The lye raises the boiling point of the water and alolows you to get to the required temp.

You have to be careful and don't let aluminum anywhere the solution. It will disolve it on contact.

Here's more information on how to do it. I think the solution they use is different but the result is essentially the same.

http://www.rugerforum.com/phpBB/viewtopic.php?p=116322&sid=5b9fa94ee7c1c7cf732dfd378daf415c#116322

Hope this helps.
Patrick
Click to expand...

I just read that Ruger forum on the subject. My suggestion is to play it safe and go through Brownells for all your bluing needs. They have everything you need at fair prices and will talk you through any problems that arise.

I like Oxynate number 7 for hot bluing. It needs to be mixed to boil at 292 degrees. Ive had great results but lately I just send my gun/knife parts out to Mel Doyles. Hes done this for 30 years. I cant mess with it for what he charges.
 
yeah I second being really careful with the stuff. I was hot bluing a guard and ended up with a ton of small minor chemical burns. Oxynate 7 is nasty stuff
 
There is also nitre bluing but the temp to get a nice blue is about 600deg. With nitre salts you can get a variety of colors, not just blue. You can get bronzes, purples and different shades of blues. Sometimes 2-3 colors at once depending on the composition of the damascus.
 
Ya know, this is sorta off the topic, but I've been pondering what I'm gonna do about a piece I wanna blue. The steel guard on this piece was fire blued initially, with some lighter bronze colored highlights, and the rest darker blue. It's already attached to the blade, and there's aluminum involved. ;) Problem is, I want to reblue some areas without messing up the lighter bronzish fire-colored pieces, and am not having much luck with cold blue solution. So far out of several attempts the stuff just looks nasty.

Any tips? Is there a hot blue solution that won't react with the aluminum? Is there anything that can be applied over the lighter colored areas to mask them from contacting the solution, that would hold up to hot blueing?

I get it cleaned & degreased down to bare metal, and have tried applying the cold blue with various things such as a clean nylon paint brush, cotton swabs, etc.
 
Hot bluing with oxynate is not a precision process. You have to submerge the entire piece you want blued. That is why you blue the parts before assembly. Im not sure about the aluminum but putting oil on the parts you don't want blued should resist the blueing. When I was blueing the guard i forgot to clean the piece again after handling it and none of it got blued until I clean the piece again. So the oil from my hands was enough to prevent the bluing
 
Yeah, except I had to rivet the piece in place, and when I cleaned up the rivets, naturally I had to disturb the surface, and at very least the pins/rivets need blued too.

Maybe a test piece would be in order, but I'd likely have to get a gunsmith to do it since I'm not set up for hot blueing, and don't think it would be worth it for this one piece... I'm surprised that just that little bit of oil was enough to prevent it from working. I'd a figgured the solution being that hot would boil off the oil. At least I'm not sure I want to take a chance on it 'cause there won't be a second chance to redo the bronze colored areas... I wonder if painting them with nail polish or super glue would withstand the heat?
 
I have had sucess with a blueing process from Brownells "Mark Lee Formula 1". You only need to get up to boiling water temp. Its a rust blue, but very dark, even and durable. It is important to thoroughly degrease prior to using it. I have used the degreasing stuff from Brownells. With the lower temps, you could probably coat parts with nail polish to block the blueing. With the oxynate blueing, only put aluminum in it that you do not want to see again, as it will dissolve it.
I have reblued/restored guns it the Mark Lee that came out witha high quality finish. Its a lot less expense and trouble than oxynate. Could be done in a pot over a hot plate.
Chip Kunkle
 
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