double-gun question

[Long John]

Friends,

I have a question.

If you had to solder the barrels of a side-by-side double gun together what solder would you use?

Thanks for your reply.

John Cholin

[L. Akers]

A low temperature lead/tin alloy solder is used for this purpose.  The heat required to melt high temp solder may warp the barrels.  I would use 50-50 solder.  It melts well below 600 degrees and is the strongest  of the lead/tin alloys.  Remember the solder will melt and flow TOWARD the heat source.

[Tim Crosby]

 I can't wait to see where this is going, as in the finished product.

  Tim C.

[David Price]

Long John

Brownells has a solder that melts at a very low temperature and is supposed to be much stronger than plumbers solder. 
It is called force 44.  Also  get the liquid fluxt that they recommend. 

I use it to put my swivel breech barrels togeather and it is a pleasure to work with.  When I first purchased it I tested it by soldering two  six inch pieces of barrel that I had previousely cut off, placed one barrel in the vise and commenced to hit the other  several times with a very large hammer.  It stayed toigeather.  I have put many barrels togeather and have never
had any problems with them.

David Price

[Captchee]

 I have used force 44 and it works well . I also have used  silver solder . However if I  I was inclined to do the job again , I would build a furnace setup like jerry Huddleston has  and either high temp or braze the ribs .
Maybe jerry will chim in  with his details

[jerrywh]

The process I used is very complicated. I was told by two of the best American shotgun smiths that it couldn't be done. There is only one company that I am aware of in the world that brazes shotgun barrels together.  Razzini in Italy. They use a hydrogen furnace I think.
 In any case it is too complicated and expensive for the case at hand. I have a special electric furnace but that is the easy part.  I plan to write a book on some of this stuff when I get about 90.
   The common method used today is to braze the breech end together and solder the rest of the tubes. This is not difficult to do.
 A small flat should be filed on the breach end of both barrels where they join. If you look at a set of shotgun barrels you can see this. Clamp the two together at the breach. Lay them flat out on a piece of steel or even a board t keep them parallel. With a torch braze the two breech sections together. It is best to stay about 1/2" from the ends so as not to mess up the ends of the barrels. You only need to braze a section about 3/4" long.  Don't worry about warping. It doesn't matter down at the breech and will not weaken the barrels  just let them cool slowly. Don’t quench them.  The best solder for the ribs is the low temp silver allow. It has a melting point of about 430°F In my opinion.  
If you get  the high force 44 from Brownel be sure not to get the high temp.  The high temp has a lot of Cadmium in it .  Not good to breath
 Get an old junk set of barrels and practice on them.

[Acer Saccharum]

Is this rifles or shotgun barrels?

I don't know much about this business of double barrels, but I like the idea of higher temp at the breech. This could allow one to tack the muzzles together wit soft solder, then see how they shoot. If not shooting at the same elevation, melt the solder and reposition.

[Mike Brooks]

You have to use rosin for flux and 50/50. Acid flux will eat your barrels over time.

[jerrywh]

You don't need to worry too much about regulation of a shotgun.  Basically you want a converging pattern at 30 yds. Most  antique  shotgun barrels are not straight they actually bow in towards the center in the middle and the bores are about parallel for the last six inches or a foot and they look good like that. The gun will shoot were the last 6" of the barrel points. So when you set them up you will need to put some spacers in the middle at a couple of places.
  Like I said get an old set of barrels and tale them apart. Best not to get Belgian barrels because they will be brazed together. Get old American or English. Junk ones on EBay are cheap at times.

[Long John]

Thank you, all for your feedback.  It has been most helpful!

Its times like these when I must pause for a moment and think about how wonderful this forum is.  We are a community of gun-makers sharing our experiences and knowledge with other kindred spirits.  We are all crazy, of course, and some crazier than others.  But we are a community, helping each other.  That's a great thing if you take a moment to think about it.  I just did.

Best Regards,

John Cholin

[Clowdis]

The Force 44 solder from Brownells is fine and will go through a hot bluing process but I don't like the flux they sell for it. I seems to just turn black with me. I prefer the paste flux Oatey no. 5. Doesn't discolor and flows great. I've put double barrels together with this combination out of necessity but would prefer to leave this operation to someone else.

[gunmaker]

As a glutton for punishment, I'm thinking of trying a SXS...And as a retired welder why not wire weld the breeches about 1" top & bottom ?  70,000 lb. series wire should do it.  I'm going to weld up some stubbs and see for myself ?? any thoughts ?....Tom