Hot Bluing

Discussion in 'Technical Questions & Information' started by ShawnDow, Jul 19, 2012.

  1. ShawnDow

    ShawnDow Member

    Jun 17, 2012
    Tawas City, Michigan
    Any one out there do Hot Bluing... Ive done cold bluing (Birchwood Casey) with mixed results; lots of re-do's to get it right... with a ton of patience and a "clean room" I'm sure I'd nail it the first time round. I see Brownells has "kits" and as cool as they look, they just make my wallet scream in agony! Are there comparable kits to the Brownells kit at a more wallet pleasing price? If I went with the Brownells kit... how many firearms could be done with the solutions provided? Im trying to figure out cost per gun thing... Or do I just stick with cold bluing for now? And if so... is there something better and easier than the Birchwood Casey system Im using now?

    Now food for thought... :confused: if you say I'm bluing ( with no "E" ) how would you spell.. will you (blu.. blue..) my gun?

    Any way, thanks for your input,
    Shawn Dow
  2. Hammerslagger

    Hammerslagger New Member

    Jul 30, 2009
    Most so called cold bluing that comes in a bottle or tube or etc. is not actually bluing. It is, in fact, a blackened copper plating (more correctly called flashing) process that does not require external electric current.

    True cold bluing, that must be used on soft soldered double barrel sets, is a slow (usually more than a week long) controlled rusting and rust conversion process that involves some hard to get and/or nasty chemicals.

    Hot bluing basically uses a mixture of lye (NaOH, and very nasty when dissolved in very hot water) and saltpeter (KNO3) dissolved in distilled or deionized water. Bath temperatures are typically above 250F and must be held within a narrow temperature range repentant upon the exact bath composition. There are other high temperature cleaning and rinsing baths before and after the actual bluing bath.

    Having read this far, most persons will conclude that both real bluing processes are industrial processes that, really, are not well suited for the home gunsmith. If you are still not discouraged, here is a useful link:
    Last edited: Jul 19, 2012

  3. JLA

    JLA Well-Known Member

    Feb 26, 2007
    Heart Of Texas
    HS is dead on. It is good for touchups and thats it. I have best results with G96, and Brownells oxpho blue coming in close second. Birchwood caseys is bottom of the barrel as far as cold blues go.

    Just my opinion of course, but my opinion is based on my gunsmithing experiences over the better part of the last decade.

    If you can justify a hot salts tank set up, thats your best bet as far as rebluing goes. It will quickly pay for itself. Average charge for complete reblue is around 130 for handguns and 150 for long guns, give or take a 20 either way fo course depending on the shop.
  4. ShawnDow

    ShawnDow Member

    Jun 17, 2012
    Tawas City, Michigan
    So G96 and Brownells oxpho blue; I would gather, are cold bluing processes. Can I also assume that the two you stated can be used for complete "re-bluing" (if thats what we want to call this chemical reaction). Im just looking for something better ( more durable and easier to work with ) than what I'm already playing with.

    And thank you all for the input you are giving guys (and gals), Im looking to make my hobby more than just an A.D.D. side effect :eek:... Of course it took me 39 years to figure out I had it.

    Again, Thank you
    Shaw...Squirrel..n Dow
  5. Hammerslagger

    Hammerslagger New Member

    Jul 30, 2009
    Brownell's and others used to sell better so called "cold bluing" products than they do today. The EPA and product liability concerns forced formula changes.

    Again, any fast, low temperature cold bluing chemical (or process) is really just copper plating (flashing) with and added ingredient to turn the copper black.

    Real cold bluing takes at least a week and is very labor intensive. There is a fast hot bluing method (500-600F) that does not involve chemicals; but it is not very durable, as the blue coating is very thin.

    Hot bath bluing is an industrial process that involves really nasty chemicals and risks for the non-professional.

    Hope this pretty much covers the subject.
  6. Helix_FR

    Helix_FR Active Member

    Apr 14, 2009
    Imperial, MO
    I do hot salts bluing. Unless your going to do multiple guns at least every now and then its cheaper and easier to either pay someone to hot salts blue for your or take your chances on cold blue. Even if you do a bare bones system (2 tanks, 1 burner, 1 stand and 40lbs of salts) your looking at 600 bucks just to start and that does not include any baskets or safety equipment or ventelation equipment. Though it provides a superior finish, the stuff is just dangerous and messy. When my tanks are cool, the salts will climb out of the tanks. Its a constant maintanance thing. Its not something you can buy, set up, blue a couple things then let it sit or dump it. You have to be super careful with it when using it. Have you ever gotten fiberglass in you skin then you sweat and it burns?. Well thats what the steam will do and it don't stop unless you neutralize it quickly. Things get much worse then just that if exteme caution is not used. Long sleeves, face mask, rubber apron and big thick gloves are a must and when its 102 outside, it sucks. Plus the superheat or boiling point of the salts I use is right at 300 degrees. Stainless blackening salts are in the 600 range. I do it out of necessity of my profession. Just because you might need it is not a option. Call a local smith that blues guns (not all smith do) see what they will charge to blue a preped gun. I only charge 70 bucks. You'll burn though 70 bucks in cold blue sometimes trying to get it right and dark depending on the steel.
    Last edited: Jul 19, 2012
  7. Hammerslagger

    Hammerslagger New Member

    Jul 30, 2009
    Post #6 pretty much sums the subject up.
  8. jack404

    jack404 Former Guest

    Jan 11, 2010
    i do it here , but not often enough to run it full time which give the best results , stability of chem salts and temp is the key

    and keeping everything clean, separated and have the next process ready to go so there is not time for anything to accrue oxides along the way , exposure to air will accrue oxides, its called rust and start the moment oxygen hits the metal ..

    theres some book here

    take a read and see whats involved to get the various hot blues
  9. goofy

    goofy Well-Known Member

    Feb 7, 2011
    Hot bluing is NOT for the untrained!
    This is VERY dangerous the salts are at brought up to 295 degrees a rolling boil (the kind I use) and will burn you really bad.
    You have to be prepared for Spits, splatters and steam.
    If you are not fully covered as Helix said and with rubber boots you will get burned. I also have a shower set up to get under if there is a problem.
    This is not a system for beginners you need to know what you are doing BEFORE you do it.
    This is not a learn as you go type of job.
    My prices start at $150 for long guns and is dependent on how bad the steel is. The worse the steel the more prep it is going to take.
    I would advise that if you don't have any training in this you do not try it.
  10. CHW2021

    CHW2021 Well-Known Member

    Feb 16, 2009
    Gentlemen, this is exactly why I have either used Oxpho or sent my guns out to be done. It is simply not practical or affordable for anyone to hot blue 1 or 2 guns.
    Thank for the details.
  11. Treeman53

    Treeman53 Member

    Aug 30, 2009
    Fairview, Pa
    Traditional "Rust Bluing", or "Browning" is labor intensive, but can be a relaxing hobby. I use the browning solution from, and it works well. I've done a good number of guns for people, both blued and browned, and they always seem to look better than hot tanked bluing. All you need is time...
  12. Jim K

    Jim K New Member

    Dec 6, 2009
    Local gunsmiths who do tank blue are pretty scarce in some areas due to the various federal, plus state and local, rules and regulations. EPA, OSHA, and a dozen other "alphabet soup" agencies get into the act and make things tough for the folks who do rebluing, especially if they employ others or have shops in built-up areas.

    Anyone wanting to set up a rebluing shop would do well to read some of the above posts (goofy's is one) describing what is needed, as well as read and heed all the zoning, HAZMAT, pollution, etc., rules and regulations. In fact, I recommend hiring an attorney as the first step in setting up a bluing shop. Another often overlooked area is insurance. You not only need to be able to cover mistakes ("Gee, I didn't know those salts would dissolve that alloy frame drilling, and it was worth THAT much....") but also theft, fire and other problems or injuries.

    One recipe for disaster: Seventeen year old Joe Klotz XII, only son of anti-gun Senator Joe Klotz XI, and his buddies break into your shop one night and Joe XII manages to upset your hot tank all over himself, thus making sure there will be no Joe Klotz XIII. Daddy and Mommy, sure their darling would never commit a crime, bribe a judge to find you liable for keeping an attractive nuisance.

  13. JLA

    JLA Well-Known Member

    Feb 26, 2007
    Heart Of Texas
    HelixFR does my bluing.. Dudes a freakin pro!
  14. ShawnDow

    ShawnDow Member

    Jun 17, 2012
    Tawas City, Michigan
    Ok, guys.. hot bluing is out of the question for now... So next question for y'all. This cold bluing... Oxpho-blue you mentioned, can you dip parts in it to make it even? or does it HAVE to be rubbed on? If you can dip it.. will it hurt anything if it goes down the barrel?
    Thanks for your time,
  15. Jim K

    Jim K New Member

    Dec 6, 2009
    What HS calls "true cold bluing" appears to be rust bluing, which is not really "cold" blue as the parts normally are boiled or a heated cabinet used to get good results. It is a perfectly feasible bluing method and done right gives excellent results. (The bluing seen on old double guns and guns like pre-1930's Lugers is rust blue.)

    The process usually called "cold bluing", which involves swabbing on a liquid or paste will cover scratches or places like buggered screw heads, but is NOT permanent and will come off quickly if oiled or handled very much.

    (Every time this subject comes up, someone claims that HE has a magic cold blue that will do complete guns, is absolutely permanent, and has been used on thousands of guns, all of which have turned out perfectly. Pardon my skepticism.)

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