When I shown how to slow rust blue I was told that this process will not effect the low temp solders used on older double guns. This makes complete sense to me because older double guns were rust blued and had low temp solder joining the ribs and barrels. I just wanted to clarify that this is correct in all cases of guns.

Just started to take in small work slow rust blueing barrels only and had a customer bring something to my attention. Apparently he took two Winchester 21's to a high end outfit and they told him that the barrels would need to be seperated, resoldered with high temp, and regulated. I can only assume that they did this to strengthen the joint and to allow for hot caustic blueing? Problem is you could tell the guy thought I was FOS in saying slow rust blueing will not effect the solder or loosen anything.

What says the braintrust.

I would be suspect that the ribs may have been loose before. Rust bluing should not cause any problems on an M21. I would want to make sure the barrels and ribs are sound before I accepted the work.

Makes sense. Doesnt seem worthwhile to do all that work if the joints were good to start with, especially on a 21. But I've heard some crazy things...

Slow rust bluing will not effect the solder or loosen anything.

rust bluing, slow or otherwise, takes place at a max of 212 deg F ...

Since we are on the subject, I was also under the impression that the temperature of hot caustic blueing isnt what seperates barrels, but the corrosive salts dissolving the solder.
Most low temp solders flow around 400-450, and hot caustic blueing only gets up to 270-290ish.

quote:

caustic blueing

KEY WORDS!

Aaron, you're right; it's not the temperature that disolves the solder.

Ithaca tried the hot-blue method one of their last runs of NID shotguns assembled just after the War. Didn't work out.
The solder got contaminated and started to break down. No way to stop or fix it but to strip the ribs and resolder.

They ended up scrapping the bbls and selling off the completed stocked actions and forends years later. All 16 and 20 gauges.

I did some work for a gunsmith in the 60's &70's that did his own hot bluing and mixed his own salts up,, a 'Mr Chemist' at heart.

He was convinced that hot blue could be used to do SxS bbls with the addition of a small amt of potassium cyanide to the salts. It would, he said, block the reaction of the salts upon the solder.
I think it (bluing salts) attacks the tin in the soft solder, or at least that's what I recall,,could be wrong,,it's been a long time.

He did quite a number that way. I never recalled him saying any coming back but then again it's not the type of thing you'd boast about if they did! There's a few things in life that are like that.

I do know a couple of the many barn cats that used to wander the shop areas died from tracking thru the precipitated dust in the hotbluing room and then stopped to lick their paws.
Nasty stuff,,I stayed right out of there.

quote:

Originally posted by 2152hq:

He was convinced that hot blue could be used to do SxS bbls with the addition of a small amt of potassium cyanide to the salts. It would, he said, block the reaction of the salts upon the solder.

Funny, I was skimming through Dunlop's book last night and I noticed that he mentioned that adding a small amount of _______ cyanide would to hot bluing salts would allow them to be used on guns with soft solder.

I though it seemed interesting, and dangerous....

quote:

Originally posted by JBrown:

Funny, I was skimming through Dunlop's book last night and I noticed that he mentioned that adding a small amount of _______ cyanide would to hot bluing salts would allow them to be used on guns with soft solder.

I though it seemed interesting, and dangerous....

yikes... mad as a hatter?
morning Jason .. hope you had a great hunting season

You're exactly right Aaron, it's the caustic salts that eat the solder and not the temperature of the bluing bath. I've rust blued hundreds of double barrels and have never had any issues with solder. I'm also not sure I understand why anyone would want to strip down a 21 and relay the ribs just for the hell of it. Model 21s were rust blued at the factory and in my opinion they shouldn't be reblued in any other fashion. The only time a rib needs stripping and relaying is if it's already loose or if the barrels have been hot blued once before, but never just so you can hot blue the barrels. A number of modern doubles can be hot blued because the companies are using solder like Brownells hi-force 44 or an industrial comparative where there is no lead. Other than that the only other doubles I would hot blue are the Spanish and Belgian guns with brazed ribs.