difference between cupper backing or ceramic backing?

[kingnero]

Are there general guidelines as to where to use either one?

Specific case: I've got a customer with a rifle barrel that is drilled through (90° from the long axis) (8 holes = diameter 10 mm at random places). It's regularly done in Europe to render guns useless. The customer wants it welded shot for cosmetic reasons. The inner appearance doesn't really matter as the action itself is also drilled and welded shut, however not very visible.
The purpose of this gun is that it will be put on show in a store for antiquities (not to be used).

It's easy enough to machine a cupper rod to the appropriate dimensions, although he wants ceramic backing as he's been told that's better. Normally we don't provide such (welding) services however in this case, as he's a friend of the boss, we have to.

We do have MIG, TIG and stick welders in our facility, also the option of chroming, hot Zn-layering, and bluing (which will also be done after grinding the welds to fit the barrel circumference).

I'd say Tig (low amps, never letting the barrel getting hot) with cupper backing, however I'm not familiar with ceramic.
Can they be machined, availibility, ... I'll find out if they are preferred for this kind of work.


Your opinions please?

 

[unclesyd]

What is the barrel made of?

Either one will work thought it might be easier to remove the ceramic.

It seems odd that if this gun is only going to be a show piece and the bolt is welded closed why go to all the trouble to keep the bore open. Why not use a steel rod or plug?

 

[kingnero]

Barrel is made of WW1-era steel. That's a euphemism for I have absolutely no idea. Does it really matter?


The less filler metal that goes into the barrel, the slighter the chances of it warping. Hence keeping the bore open instead of filling it up.


If both (Cu and ceramic) can be used, I'll go for cupper as it's easyer to acquire (we have it lying around) and no problem to machine to fit the barrel.

 

[DVWE]

I would put a pressed plug in each hole, and push it just slightly below the outer surface. That way, you only have a small amount of welding to do (less heat) and you don't have to worry about backing at all. That is essentially what we call a plug weld in the welding world.

 

[unclesyd]

Appreciate the feedback.

I'll try to contact a friend who works on on old guns, like to )3 Springfield Rifle. The reason I ask about the material is that some of the older barrels were made from the higher carbon steels AIS 1045/1050 which could be somewhat difficult to weld. The majority of today's barrels are from AISI 4140.
Many years ago when I worked in a foundry we melted down thousands of 03 and M1 Garand barrels that were spiked with a rod welded into the end of the barrel and bolt the closed bolt soldered.

 

[Compositepro]

You should not need to weld the plug. Just press fit the plug and grind flush. There will be no visible seam.