More on rust blueing a barrel.

[ccdjg]

There was quite a lot of interest about rust blueing in an earlier thread http://www.airgunbbs.com/showthread....t=rust+blueing, so I thought I might share the results of one of own mini-projects which I have just completed. Basically I had made an octagonal pistol barrel as part of another project to build a reproduction antique air pistol, and I wanted a sympathetic antique grey-black finish rather than a deep glossy black. I have only experimented with hot alkali blueing in the past, and although I could get excellent results (here is an example: http://i135.photobucket.com/albums/q...stored.jpg?866 ) you have to admit that this sort of black would be out of place on any antique weapon. So rust bluing seemed the best way forward.

After reading through Angier's great book "Firearm Blueing and Browning" I was more confused than ever by the vast array of rusting recipes, some containing as many as six different metal salts. Working on the theory that simplicity is best, I eventually opted for a 2% solution of ammonium chloride ("sal ammoniac"), which according to Angier was used to recondition first world war rifles when no other chemicals was available, and could give a good deep black finish. Ammonium chloride had the added advantages of being completely harmless, cheap, and readily available from the internet.

The barrel was polished to a satin finish (a high polish is not recommend for rust blueing) and is shown at the top of this composite picture: http://i135.photobucket.com/albums/q...psd931c88b.jpg. After thorough degreasing with acetone followed by toluene (any solvents like white spirits or methylene chloride would have done) it was wiped over thoroughly with the ammonium chloride solution (rubber gloves!) and suspended inside a plastic container above some kitchen paper towels soaked in water. The whole container was placed in an airing cupboard (you need an understanding wife for this part) to ensure that the whole system got warm, and not just the water at the bottom. If you just heat the base you are liable to get condensation on the barrel with lousy results. After 24 hours the rusting was rather patchy but after boiling in water for 5 minutes and rubbing down, you can see from the bottom of the picture that the results weren't too bad. The process was repeated again http://i135.photobucket.com/albums/q...ps0c6ce767.jpg
and then repeated for a final third time http://i135.photobucket.com/albums/q...ps65b3a1ea.jpg

I found that the rusting became much more uniform and satisfactory as each pass progressed and I am sure that I could have continued with one or two more passes to get a much deeper finish, but for me the result after the third pass was ideal, so I called it a day. I was very happy with the result when the barrel was fitted to the rest of the pistol.

[Troubledshooter]

Thank you for posting that, John.
I've only ever attempted some minimal cold blueing in the past, with varied results, so I'm sure your post about a relatively hazard free method will give food for thought, should the need arise.

[thisisdonald]

Yes dave, im reading this!

Great post john.. thanks mate..

[Peter Dunkley]

Thanks john. I am certainly going to have a go when the weather gets a bit warmer. My problem so far is finding a boiling tray big enough.
The ammonium chloride tip is good news. I was wondering what to use. There are several brews available in the states but not here.

[Garvin]

Thanks for that tip, John. As David says, a non-hazardous blueing technique is most interesting.

My attempts with cold blue gel haven't been anything to write home about, except dunking new steel screws in the stuff seems to work brilliantly - it's obviously the kind of raw surface the chemical really likes to bond to.

[ccdjg]

Thanks john. I am certainly going to have a go when the weather gets a bit warmer. My problem so far is finding a boiling tray big enough.
The ammonium chloride tip is good news. I was wondering what to use. There are several brews available in the states but not here.

Instead of a boiling tray, have you thought about the steaming method for converting the brown rust to black? You could use a plastic drainpipe and a wall paper stripper steamer, connecting the two with a suitable hose pipe. It doesn't matter if the barrel or gun touches the sides as this step is not sensitive to this.

I used this technique to steam a length of wood for bending and it worked fine.

[Troubledshooter]

Another excellent tip, John.
Keep 'em coming.

[thisisdonald]

Instead of a boiling tray, have you thought about the steaming method for converting the brown rust to black? You could use a plastic drainpipe and a wall paper stripper steamer, connecting the two with a suitable hose pipe. It doesn't matter if the barrel or gun touches the sides as this step is not sensitive to this.

I used this technique to steam a length of wood for bending and it worked fine.

very interesting - you know I think you could actually use the same container for both processes... if you designed it right!.. Ill be having a bash at this, and if it works, Ill have a stainless boiling tank with electric immerser for sale!!

[Peter Dunkley]

Instead of a boiling tray, have you thought about the steaming method for converting the brown rust to black? You could use a plastic drainpipe and a wall paper stripper steamer, connecting the two with a suitable hose pipe. It doesn't matter if the barrel or gun touches the sides as this step is not sensitive to this.

I used this technique to steam a length of wood for bending and it worked fine.

SOLVED Why didn't I think of that??

[T 20]

Great post John

I've been having trouble with rust formation in damp weather with Fume Bluing so your information is a great help --- thank you.



All the best Mick

[valboskie]

Yes dave, im reading this!

Great post john.. thanks mate..

very useful information john thsnks for sharing

Donald I will have to up the tempo In getting my rifles ready for bluing you will have tbis cracked by the weekend lol
atb
David

[big bad bear1]

fantastic tip, but what could those of us who don't have airing cupboards use to maintain a warm enviroment if you know what i mean?
atvb
Dean

[ccdjg]

fantastic tip, but what could those of us who don't have airing cupboards use to maintain a warm enviroment if you know what i mean?
atvb
Dean

In actuality you don't have to have a warm environment, its just that the warmer it is the faster the rusting. If you just keep it somewhere in the house at a comfortable room temperature it should still rust OK in 24 hours. Why not put it in front of the telly so that you can watch it rust - much better than some of the current programs on the box.

[micky]

That's a great bluing job, it's the ideal finish on any old gun as it's not over the top well done.

[big bad bear1]

In actuality you don't have to have a warm environment, its just that the warmer it is the faster the rusting. If you just keep it somewhere in the house at a comfortable room temperature it should still rust OK in 24 hours. Why not put it in front of the telly so that you can watch it rust - much better than some of the current programs on the box.

how very true lol