doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com What bad things happen when a double is nitre blue

I am curious as to what and when the damage is done to a double barrel that has been blued incorrectly (hot blue). I have heard the solder is or could be damaged by the process resulting in loose ribs. If a double has been nitre blued and survived the process with ringing barrels and no visible damage will it remain "OK" in the foreseeable future? Is there a possibility of any residual salts continuing to eat the steel and thus cause a loose rib later on? If the gun remains solid after a nitre blue would a proper slow rust browning mitigate the potential for a loose rib problems later?

Nitre blue and hot blue are 2 different processes. Double barrels that are soft soldered together must be rust blued. If a set of soft soldered barrels are hot caustic blued, the residue left behind attacks the tin in the solder and destroys the joint. This can take years to happen, but it will. Never ever hot caustic blue a set of soft soldered tubes, the residue is almost impossible to remove short of removing and relaying the ribs.
Steve

The Brownells Nitre Blueing salts are heated to around 600F which is over 200F above the melting point of most of the solders used in most sxs gun barrel assemblies. 60/40 solder melts well below 400F
http://www.brownells.com/aspx/ns/store/P...0BLUING%20SALTS

There will be nothing but separate parts left in the bluing tray if this is the case.

Thanks for the responses. One of my questions remains, if a double was improperly hot blued, would a proper rust bluing remove/neutralize any residual salts from the hot caustic bluing? I was told by a well recognized smith that if the gun is not presently showing a loose rib at this time the rust bluing will neutralize and or remove the residual salts from the hot caustic blue and help insure the guns ribs remain tight to the barrels. I looking for confirmation or not.

Re-blueing by rust blueing will not do anything to "neutralize" the effect of the salts, based on what Oscar Gaddy said. My recollection of what he said was that the salts started a conversion of the tin and it was an autogenous process that continued regardless of intimate continued contact with the salts.

From what I gather based on Dr Gaddy's information, I'd say the best that you could do would be to ensure all salt is removed by whatever means you think best. I would boil them for a few hours with the front sight out and a hole in the under rib, under the forend. After that, if they don't show signs of looseness, I'd use the gun until it became a problem, then re-lay the ribs after totally removing the old solder and re-tinning.

The ONLY way to be sure would be to strip and relay all the ribs(top,bottom,splinter) and the forend loop and then properly rust-blue barrels.