Need heat bluing help guys!

rhrocker

rhrocker

Joined
Jan 18, 2004
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I have some 01 bolsters that I want to heat blue. I've tried my little salts heat bluing set-up (it consists of some Brownells Nitre-blue, and a lead melting pot and thermometer, and gets up over 650 very easily), but I keep getting splotchy (!?) results. I'm sure it's contamination in the salts themselves, or on the metal. I'm cleaning them with everything I know what to use, but it's still there.
Using this system takes time, and is messy, and probably a little dangerous, although the amount of liquid salts is about 2 cups (would still smart to spill that onyour toes!).
So, I'm thinking, why not use the Evenheat kiln. Run it up to 550, put the 01 in there, wait 10 minutes, and see what I have. Then, increase the temp if I need to. Is there any reason this won't work?? Shouldn't it blue just like the salts, or am I missing something here?
Also, how to quench the 01. Since these are bolsters, does it matter if I just drop them in water when the color gets where I want it, or should I simply take them out of the oven and let them air cool. I know that 01 is a oil quench, but I'm not going for hardness here.
Thanks!
Robert
 
I think the nitre salts make a deeper bluer-blue than just plain heat because of the lack of oxygen. Straight heat bluing makes it a blacker blue, if that makes sense.
 
Hey Jeff, what if I put them in foil first? I'd have to have a sample piece of 01 laying next to it, to see the color change. Anyway, maybe that would help on the O2 thing.

IG, no lead. I bought the little electric pot on ebay just for nitre blue salts, and it came in a new box and all. Still, there was oil in the pot to keep it from rusting I guess. Maybe I didn't get it cleaned out good the first time.
 
Robert I don't have direct experience with this but I think the nitre blue would be much hardier (I made that word up! ;) ) than heat bluing. You will want to quench the bolsters when you get to the color you want or they'll keep changing; I use water but haven't blued O1 parts either.

There's certainly some contamination in the process somewhere. If it were me I'd ditch the salts, clean the heck out of the pot, and start over. Your setup sounds like just the ticket. When you get it refined I'll copy you. :D
 
Robert, A couple years ago I was into coloring some of my blades with heat. One of the things I was doing was coating the blade with Minwax paste and just running a normal heat treating cycle. At 350 degrees I was getting a maroon, at 400 a very dark blue. As soon as I took them out of the oven I put another coat of wax on. Just happened to think about the blochiness you are getting, it is most likly the results of not having them supper clean when putting them in the salts.
 
I don't have any experiance hot bluing 01 with nitre-blu but I have done lots of damascus bolsters. I use an old coffee can to hold my salts and they have all kinds of junk in them. I have no problem with getting even colors on the damascus. There should be no reason to quench anything because it has not been brought up to a quenching temp. All I do is put the bolsters in the heated salts, get them to color, remove them from the salts to cool and then rinse the salts off with tap water.
 
I heard my name mentioned here. When I get blotches from nitre bluing it is always from oil, wax, finger prints or buffing compounds left on the steel. To see if the part is clean enough hang it from a stainless steel wire and dip it in clean water (from a clean container) pull it out and a see if the water beads up like on your freshly detailed Porche Roadster wax job. If it does they will be spotty. I use diluted Dawn dish detergent and paper towels and redip to test. Dont touch em again. Read the lengthy instructions from Brownells on any bluing salts and call them if still having troubles. They are good people and talk slow enough for me.

Heat bluing is best done with the same cleaning method but use a digital oven for repeatable results. Experiment for best results
 
I appreciate all of the ideas guys. I'm going to clean them using Bruce's instructions, and try and heat blue them using the temps that Raymond uses. Art mentioned that it's not necessary to quench them, because they aren't at quenching temp. That's true, but I was doing it to "stop" the color change. Maybe this isn't necessary? One thing that has me puzzled is that I think the steel should be dirt, oil, and grease free, yet Raymond puts Minwax on his, and still gets good results, so maybe the heat burns the wax off while in the oven? Anyway, as usual, you've all been great help.
(Dave, "Hardier" sounds good! :o)
 
Robert, Here's a knife from 3 years ago. The blade is 5160 with a mustard patina. I did the patina after the first ht cycle. I then coated it with Minwax and ran it again for another 2hrs at 350. Normally 500 degrees will produce a nice blue without the wax but at the lower temps the wax makes a big difference.
PDRM0297.JPG
 
Thanks Raymond, and Tom, I don't know that name, sorry. I bought my salts through Brownells. As an update, I spent several hours at the shop experimenting with 3 different thicknesses of 01, at various temps. I'll heat blue the actual bolsters tomorrow, but just to let you know, a temp of about 560 produced a real nice blue on a 3/16th's" thick piece, golden bronze on a 1/4" piece, and dark, dark blue/black on a 1/8th" piece. The two sets of bolsters I'll do tomorrow, are the same thickness, so I'll simply check the oven quite often on it's way to 600, and when it's right, I think I'll air-cool them (unless someone tells me that they can change color as they cool, at which time I'll h20 cool them.)
 
Robert if you're heat coloring I think I'd quench when you get to the color you want. May not make any difference but I've always done that just to make sure I get what I think I'm getting. But I've only done Ti, don't know whether O1 would be the same.
 
ddavelarsen said:
Robert if you're heat coloring I think I'd quench when you get to the color you want. May not make any difference but I've always done that just to make sure I get what I think I'm getting. But I've only done Ti, don't know whether O1 would be the same.
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Ok Dave, I'll put in a piece of scrap 01, and when it gets close to the color, I'll quench that piece and see if it remains free of problems (and it should). Then, when the right color hits the bolsters, I'll dunk-em! Gotta be SO DARN careful about scratching these darn things though. I had a tiny screwdriver just barely touch the surfact of a blued bolster once, and that's all she wrote. Not durable at all. So why am I even doing it? Customer request. Also this is the last custom order I'm taking. From here on out (well, actually I still have 5 on the books) I'll just build something, and post it for sale. Less stress.
 
rhrocker said:
Also this is the last custom order I'm taking. From here on out (well, actually I still have 5 on the books) I'll just build something, and post it for sale. Less stress.
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and less money :eek: :)
thinking about why the different colors of the different sizes..
Mete mentioned about heat and the colors concerning heat treating and why, back some time ago. maybe he can remember where it is or elaborate on it.
 
Dan said: "and less money "

Very true, but I'm mostly a woodworker by trade, and knifemaking is still pretty much a fun (albeit expensive) hobby. I'd love to be a full time knifemaker someday though.
 
rhrocker said:
Dan said: "and less money "

Very true, but I'm mostly a woodworker by trade, and knifemaking is still pretty much a fun (albeit expensive) hobby. I'd love to be a full time knifemaker someday though.
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yes your right you gota keep it fun..

idea
charge a lot more for the custom orders ;)
it makes them a lot more fun to do :D
 
Bluing in salts is more durable .If you are getting splotchy results something is contaminated. Gunsmithing bluing tanks are made from plain steel. If you contaminate the part or tank with things like copper especially you'll have a problem. Heat bluing doesn't require quenching .
 
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