DIY hot bluing


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martysport
January 25, 2011, 09:10 AM
I put a nice big scratch on my Pietta 1858's cylinder :banghead:
Looking at pictures various people have posted of their revolvers it seems a common thing the cylinders getting scratched.

The scratch was mainly just cosmetic so I tried to touch up with some cold blue I had, what a waste of time :cuss: it just took off what blue was left on the cylinder making it look terrible so I decided to have a go at DIY bluing.

1st I polished off what mess was left with some fine sandpaper finishing off with some wire wool to bring it down to bear metal and a nice finish.
I then made a hot blue homebrew and after a clean with acetone I hot blued the cylinder. When done I left it in a tub of old engine oil overnight.

What do you think of the results? I'm fairly pleased :D I might have a go on my Marlin 25N's bolt sometime.

http://martysport.webege.com/blue/1.JPG

http://martysport.webege.com/blue/2.JPG

http://martysport.webege.com/blue/3.JPG

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robhof
January 25, 2011, 09:26 AM
Darn nice, outright professional. I've had mixed results with cold blues on my guns too, it either looks pretty good or downright terrible.

junkman_01
January 25, 2011, 09:26 AM
That looks pretty fine to me. Can you divulge your 'home brew' bluing recipe?

Trad Archer
January 25, 2011, 10:41 AM
Very nice. Would love it if you didn't mind sharing your secrets.

martysport
January 25, 2011, 10:51 AM
That looks pretty fine to me. Can you divulge your 'home brew' bluing recipe?

Sure :) but remember to use common sense and protection!!!!!!!!!!!!!!!

Just normal household caustic soda (http://en.wikipedia.org/wiki/Sodium_hydroxide) and Potassium nitrate (http://en.wikipedia.org/wiki/Potassium_nitrate)

I mixed it in a 2:1 ratio with distilled water (aka demineralized water)

For the small batch I did here's the exact recipe I used.

1 litre of distilled water
650g of caustic soda
325g or potassium nitrate


1st thing is SLOWLY add the caustic soda to the water (I used a small stainless steel saucepan) stirring all the time untill it disloves. It will get HOT and if you add it too fast it will boil over and go everywhere!!!!! best do it outside as it gives off some nasty fumes too.

When thats done add the potassium nitrate (some say you can use sodium nitrate fertiliser 15-0-0 or 16-0-0 but as I couldn't find any I can't confirm or deny it works) slowly stirring all the time.
Once everything is disolved place it on some heat (I used a gas ring) and slowly bring it to the boil. When it is boiling place the part you want to blue into the solution bear in mind the part MUST be DRY and spotless. Place the part so it is not touching the bottom or the sides of the pan/pot, I just suspended it from a bit of old steel wire and a BBQ skewer.
If you read some other recipes/instructions it says it take between 10-40 mins, I can confirm that wasn't the case for me. It took about 2 hours!!!!! the water will evaporate so you will VERY CAREFULLY AND SLOWLY need to add some more water (at arms length wearing heavy gloves and full face shield) Keep the mixure so it's boiling well all the time but don't overheat it or the water will be gone in no time. A slow rolling boil is just that little bit too cold so bring it to a slow rolling boil and give the gas just a little tweek higher and that will be spot on :)

Once you are happy remove the part and place into a pan/pot of VERY hot but not boiling for 10 mins then remove from the hot water and place into a pot/pan/tub of old used engine oil overnight (or 30 mins if you can't wait :neener: )

Please remeber this is VERY dangerous, if you get hurt it isn't my fault.

damoc
January 25, 2011, 08:22 PM
very cool i just learned something new

thanks

Bluehawk
January 25, 2011, 08:58 PM
what role does the soda play in the blueing process?

o Unforgiven o
January 25, 2011, 09:07 PM
Why the soak in motor oil?

Also if you were to finish up the bluing process minus the oil (which I assume is a finishing step) could you do the bluing process over again for a deeper bluing to get a more robust finish?

Oh and one more thing, is there any way to get a more matte finish?

avan47
January 25, 2011, 09:36 PM
The matte finish is in the steel. The more highly polished the part is before bluing, the more highly polished the finished product will be. You might try finishing the part with about 240 sand paper before bluing to get a matte finish.

martysport
January 25, 2011, 11:25 PM
what role does the soda play in the blueing process?

I don't know the EXACT role it plays, better ask a chemist.

Why the soak in motor oil?

Also if you were to finish up the bluing process minus the oil (which I assume is a finishing step) could you do the bluing process over again for a deeper bluing to get a more robust finish?

To neutalise the bluing process, if not your part will corrode :)
You can use WD40 instead if you like, I used old oil and it worked for me. Try something else and see what happens, it might be better.

As for re-bluing, there is only so much that you can do. If you want it deeper leave it in longer.

arcticap
January 26, 2011, 12:05 AM
Please remeber this is VERY dangerous, if you get hurt it isn't my fault.

Understood, but if it comes out really great you'll get all of the credit! :D

Oyeboten
January 26, 2011, 06:36 AM
Hi martysport,


Thanks for sharing this!

I will try it.


Is the 'Blue' you acheived a Blue-Blue? Or a Black sort of Blue? Or, how would you describe it?


Looks like a Black sort of Blue in the images.

martysport
January 26, 2011, 09:32 AM
Yea, it's more black then blue. It's very close to the original finish of my Pietta 1858.

madcratebuilder
January 26, 2011, 09:59 AM
You can buy a ready made blue from Brownells called Art's Belgian Blue. You use boiling water, about six to eight applications with carding and boiling each time. Surface finish well effect the amount of gloss.

This was finished with worn 320 paper and has eight coats of Art's.

http://i32.photobucket.com/albums/d37/madcratebuilder/snuubie1101.jpg

martysport
January 26, 2011, 10:05 AM
Nice finish :) but it's not proper hot bluing.

I assume this is the stuff?

LINK to Art's Belgian Blue (http://www.midwayusa.com/viewproduct/?productnumber=958388)

mgmorden
January 26, 2011, 11:04 AM
Excellent information - thank you. Don't have a good project to use this on right now, but I'm definitely filing away the "recipe" for later use :).

Jim Watson
January 26, 2011, 11:21 AM
The main purpose of the caustic soda (sodium hydroxide, lye) is to raise the boiling point of the solution to where the nitrate will oxidize the surface of the steel to black iron oxide. That is usually about 285 deg F.

I have read but not tried that about any common fertilizer nitrate will work; potassium nitrate, sodium nitrate, even ammonium nitrate. But if you use ammonium nitrate, better work outside and stand upwind, the free ammonia will be rough.
The old gunsmith book recipes had all sorts of combinations of nitrates and nitrites but the simple solutions seem to work ok.

martysport
January 26, 2011, 11:38 AM
The main purpose of the caustic soda (sodium hydroxide, lye) is to raise the boiling point of the solution to where the nitrate will oxidize the surface of the steel to black iron oxide. That is usually about 285 deg F.

Its good to know how and why :) thanks.

AFAIK ammonium nitrate is banned in alot of countries :eek:
Great stuff for DIY explocives ;)

Bluehawk
January 26, 2011, 08:04 PM
Thanks Jim for that explanation!

The matte finish is in the steel.

If you want a great matte-black finish you will need to sandblast the parts before blueing.
If you want to experiment with fertilizer-grade pot nitrate be sure it's the soluble type and not the prill as the prill has clay in it.

Geneseo1911
January 26, 2011, 08:13 PM
Thanks for the awesome write up. I'm going to have to do this one of these days. I've always wanted a super high polish 1911....maybe I can just do it myself to an old Springer...

rhodco
January 26, 2011, 08:23 PM
Is this process just for steel, or do you think it would work for an aluminum frame as well?

swampgeek
January 26, 2011, 08:53 PM
Could a good rust inhibitor due the job of the oil bath? I have tried cold bluing with varying results.

Rhodco best I know you cant blue aluminum, you can "Black" it though, Birchwood Casey makes a product called Aluminum Black Link Here (http://www.brownells.com/.aspx/pid=4941/Product/ALUMINUM_BLACK). Dont get me lying on the how the process works but im sure it is just as easy as cold bluing.

junkman_01
January 26, 2011, 08:56 PM
Is this process just for steel, or do you think it would work for an aluminum frame as well?
DO NOT try hot dip bluing on aluminum. It will dissolve the gun!

Jim Watson
January 26, 2011, 09:06 PM
The sodium hydroxide in the hot blue will dissolve aluminum.

At one time it was popular to use Drano to strip the black anodizing off an aluminum part. I have seen some that looked pretty good, if you like a white grip frame on a blue Ruger, say. But there have probably been some ruined that way, too.

Jaymo
January 27, 2011, 12:42 AM
The original formula actually called for ammonium nitrate.
Sodium and Potassium nitrate are easier to get, and don't stink to high heaven.
IIRC, you can add manganese phosphate to the mix for hard-to-blue steel alloys.

For aluminum, you need to use an anodizing formula.

I've thought about Parkerizing, and then Duracoating my blackpowder guns. The Duracoat adgeres well to the Parkerizing, and will protect the steel from rust.


BTW, the only cold blue I've had good luck with is Brownell's Oxpho Blue.

bushrod2
January 27, 2011, 07:29 AM
Great job, beautiful results. I also will file away for a project this summer,THANKS

CHM
January 27, 2011, 08:20 AM
Maybe a dumb question: where did you find the ingredients to do this? Great results! I would definitely try it, but want to make sure I get the right source for sodium hydroxide and potassium nitrate. Thanks.

martysport
January 27, 2011, 09:10 AM
Maybe a dumb question: where did you find the ingredients to do this? Great results! I would definitely try it, but want to make sure I get the right source for sodium hydroxide and potassium nitrate. Thanks.

Where do you live? (USA, UK, europe?)

eBay is a good place :)


Here's an example if you live in the US for the potassium nitrate.

ebay link (http://shop.ebay.com/?_from=R40&_trksid=p5197.m570.l1313&_nkw=potassium+nitrate&_sacat=See-All-Categories)

Sodium Hyroxide is just drain cleaner you can get in any hardwere/supermarket store.

CHM
January 27, 2011, 11:08 AM
Awesome. Thanks.

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