Hot Blueing

[mp40guy]

I am just about done with my master piece. I want to Hot blue it but don't know where to get the chemicals or how to. Does anybody know how to get'er done

[tomcatshaas]

yep, I just checked into it this week. m2ball told me to get the Nitreblue bluing salts.

http://www.brownells.com/aspx/NS/store/ ... 10&si=True

instructions

http://www.brownells.com/aspx/NS/Genera ... Bluing.pdf

[longhorn109]

Wow that looks like delightful stuff to use First time I have seen something that says induce vomiting if you swallow it. Too many chances to Feck it up and melt your face, blow your house up, cause Earth to move out of its orbit. I would let a shop do this, unless all the warnings about destroying all of civilisation are exaggerated.

[bolex]

Wow that looks like delightful stuff to use First time I have seen something that says induce vomiting if you swallow it. Too many chances to Feck it up and melt your face, blow your house up, cause Earth to move out of its orbit. I would let a shop do this, unless all the warnings about destroying all of civilisation are exaggerated.

Sounds like fun!

Really, if you are careful and use full face mask (I like them when grinding) gloves, etc it will work out. There are threads on other sites that give good ideas on how to hot blue on the cheap. I used a black oxide (cold process) from caswell and it came out perfect. Like everything else with finishing, preparation is where the work is at.

[longhorn109]

Used that black oxide stuff myself, works really well.

[mp40guy]

I am a reenactor and am planning on useing this weapon in the field. It hast to look like real blueing. Can somebody please send me a picture of the color that it turns out to be. I want it blue black not black black.

Yes I'm picky but a bad blue job makes the best gun look like crap

[SA58]

Ive never done anything as large as an MG42.. but I've done plenty of other things (rifles, pistols etc) using the blindhogg recipe..
http://www.blindhogg.com/homemadesalts.html You'll need to mix up about 3-4 times the recipe probably to get enough to cover something that big (about 4-5 gallons) and a tank large enough.

I've read through the instructions on Brownells and they're a little over done... by the time you finish they've got you believing you need to dish out the whole 2k for some elaborate set up. All you really need is a tank big enough, a stand strong and steady enough for it, and a fire big enough to go under it. I use a digital thermometer of the type with the long lead (like the type for an oven) cost me all of $15. Face shield, gloves, boots.. common sense... the stuff will be at least 260 degrees so don't get it on you. In fact, don't get it on you at any temperature because if you leave it on for any length of time you'll feel it. Having a hose handy helps. Don't let the temp get too hot or your parts will get a red/brown smut all over them. It will come off with some scrubbing and elbow grease.

Metal prep is key... make sure alll the grease is off of it.

It's not something that's particularly difficult or dangerous to do (not much more dangerous than boiling up a pot of molasses on the stove) I've done lots of rifles, receivers, etc with nothing but a coleman stove and a stainless stew pot. Should be a piece of cake for you MG42 builders.

This formula gives you more of a black than any blue... however it matches the finishes on my AK's, RC k98's, M39's and etc.

[bolex]

I am a reenactor and am planning on useing this weapon in the field. It hast to look like real blueing. Can somebody please send me a picture of the color that it turns out to be. I want it blue black not black black.

Yes I'm picky but a bad blue job makes the best gun look like crap

I don't think I would use the MG42 as my first attempt to hot blue because you have a lot of $s in it and you stated "I'm picky". This may be a time that you may want to farm this job out.

As stated before the prep is the key to getting a good finish and this is something you should be able to do. If you are set on hot blueing it I would test the material (scrap) that you made the weapon from to get a sample of what color you may achieve with your blueing setup. Good luck on whatever end up doing.

[M1 Tanker]

The setup to blue correctly can be very expensive. You need a way to degrease, a way to blast it, and the blue system. (heat, rinse, oil etc.) Like the others said, use a full face shield, an industrial apron and large gloves. Also keep a BIG bottle of vinager handle to neutralize the chemicals if you get it on you. Then run for the shower, but get the vinager on it first!

At work, we use 6 tanks. A degrease bath (thats like an acid almost), bluing bath , rinse, hotter bluing bath, rinse and 2 for oil. Do you need that much, no, but they turn out nice. I think we charge about $250 to blast and blue a MG42.

Temperature control is a HUGE thing too unless you want your blue to turn out red. Its gotta stay in a 10 degree window. Adding more salts raises the boiling temperature, remember that too. IT can be scary stuff to do, just make sure you follow the safety stuff and understand it fully. I

To get a military grade finish, just bead blast it and goto the bath. The commercial blue finish comes from buffing the crap out of it prior to bluing.

[SA58]

I don't use any of that stuff and my results are excellent. But, like I said, I use the home made blindhogg chemical mix, and it sounds like it's more forgiving than what you use in your shop. So far as temperature control... I have an excellent means to determine temperature accurately, but for the most part I know that if my solution is mixed correctly, it will start to come to a rolling boil around 255-260 degrees. That's about where I try to keep it. But, I've had it up higher than that often as water evaporated out of it and my boiling point raised. (basically, keep it at a rolling boil) If it gets up to around 275-280, I'll add some distilled water. Unless you get it crazy hot (and it shouldn't if your keeping an eye on it), the only thing I've gotten in the way of red is a bit of rust brown smut... and like I said, it comes off with a tooth brush or scrub brush in the rinse and there's a perfect blue/black under it. So far as a rinse tank, my piece comes out of the solution and into a cheap plastic mud pan full of water... then I hose it down good in the pan in the driveway, use a toothbrush to get off the residual salt/lye mixture. Then I'll get it fairly dry with some paper towel or something... lay it down on the bench on top of some newspapers and really hose it down good with some water displacing oil (WD-40) and let it sit overnight. Wipe it down the next day and hat's it. Times when I haven't let it sit overnight I've gotten a small amount of solution bloom from a crevice.. but it wipes right off.

So far as surface prep, I've sandblasted surfaces... this works well for prepping the steel, but it will give you a matte look that's a lot like black parkerizing. I don't think that's what the 42's originally looked like (or did they?) I thought it was smooth blued steel. What I usually do is to degrease as best you can, sometimes I'll wire wheel or scrub down with fine steel wool, use a diluted acid to prep the steel, rinse and dry completely before it goes into the salts. Bring your mixture up to temperature (just at a rolling boil) and put them in for 30-45min or until you feel it's done. As M1 Tanker pointed out, the more you polish the steel, the shinier, more polished your end result will be. Scratches or blemishes will show up through the blue. Also keep in mind that metals of different hardness and make ups will take the blue ever so slightly different... like welds, possibly even the WLA receiver half may come out a slightly different shade than the front shroud you welded it to. It should be barely noticeable though, especially if you were able to keep the weld under the camming piece.

Safety is always a good thing, and common sense rules the day. I've usually got the hose out anyway.. so anytime I've gotten a drop of cold solution on me it was easy to get off, and I always know right where it's at in the event of an unforseen disaster. If you get the cold solution on you, you can probably count to 10 or 15 before you start to itch.. you don't want to leave it on. If it's hot, well duh, it's hot.. don't get it on you.

I agree in that I would probably try something smaller before I graduated up to the MG, and if the MG is the only thing you'll probably ever blue in your lifetime then it may not be worth the trouble to set up. But, I've used it for lots of stuff besides firearms... and used it on quite a few firearms with a few more on deck to go.