I am a retired machinist with most capabilities for my own gun interest. I am looking at restoring a Diana grade superposed that had salt wood and as a result has some shallow rust spots on the top bbl. about 3" from the breech. While I welded all my life, never learned to TIG as I have a lifelong friend still active in his machine shop business who is really good at it. Questions are, what should I do to the spots in preparation for the welding. Bbls. will be rust blued so what would be a good filler rod, and can I expect the spots to not show after the rust bluing assuming I do a good job of draw filing to blend in ect. Thanks, John Hancock

Since the fill metal will not be an exact match of the welded metal, I doubt that you will get exact match of the bluing. I suggest that you call Browning and ask their techs/ engineers. I believe that most barrels are soldered, not welded.

Have some engraving done over the spots that you fill in.

I've done a lot of work that was black oxide coated after welding. The best blend that I've found is ER70S2 or S6 depending on the base metal.
The latter being used for metal that is not or can not be prepped as well as it should.

As far as Prep work. Strip it down to bare metal. A metal acid primer prep works well just watch where it all goes Keep it away from the solder joints.

Now tell your buddy To use 1/16" tungsten or smaller. Low heat input and over fill the pit with filler as to avoid weld sink and excessive hardening of the weld. This will allow you to file and polish back to as near the same surface level as you started without going to deep into the existing base metal.

Keep in mind you are welding on the breach of the gun where most of the pressure is during firing. Tell him to take his time and don't over heat anything. And don't go dunking the barrel in water to cool it down between welds or after.
Feel free to contact me directly if you need any other questions answered.

quote:

Originally posted by 22WRF:
Have some engraving done over the spots that you fill in.

Good idea.
They do that already on the welded on breach guns

quote:

Originally posted by The Shottist:
Since the fill metal will not be an exact match of the welded metal, I doubt that you will get exact match of the bluing. I suggest that you call Browning and ask their techs/ engineers. I believe that most barrels are soldered, not welded.

I would not call Browning; the price they quote will be about 3 times what this guy would charge. Art's Guns. He does great work and specilizes in Brownings. He did a 20 ga S'posed salt gun for me at 1/3 what Browning wanted.

http://www.artsgunshop.com/

Jim

Hello John,
Far from retired injection mold maker/ tig welder here....

Put the barrel in the lathe and re-crown it. Save the long chips from crowning and you now have filler rod in parent metal
that will disappear when blued. It's how I weld exotics that I don't have filler rod.

As far as prep for welding over rust....scrub the hell out of it with a stainless steel tooth brush. Run low amps around 50.

Thanks to all for the advise, re the metal to use for fill, I have a set of superposed bbls that were damaged beyond use and will get my bud to use some material from them on the Diana, Thanks again. John Hancock

Hey that's the way my "uncle" did the numbers on the MAC trucks :-)

quote:

Originally posted by ted thorn:
Hello John,
Far from retired injection mold maker/ tig welder here....

Put the barrel in the lathe and re-crown it. Save the long chips from crowning and you now have filler rod in parent metal
that will disappear when blued. It's how I weld exotics that I don't have filler rod.

As far as prep for welding over rust....scrub the hell out of it with a stainless steel tooth brush. Run low amps around 50.

Has anyone ever tried a laser welder for something like this? Seems it would be the perfect tool for this kind of job.

It is but the rates to get a shop that has one to weld this stuff up ain't cheep. My area Laser micro welding is $150 an hour, Standard micro welding $75 an hour.

Any form of micro welding would be IDEAL for this but not entirely necessary if the man with the torch in his hand is worth his salt. You can get damn close to micro welding levels with a regular old tig machine and some practice

quote:

Originally posted by kcstott: if the man with the torch in his hand is worth his salt. You can get damn close to micro welding levels with a regular old tig machine and some practice

Yes this is correct. In this case as in most, it isn't the arrow but the indian.

Our shop minimum for micro welding is $75

I have to raise my rates

You know, the way you describe it sounds to me like the junction of the receiver where it meets the top rib.

Look carefully..the receiver body is machilned to meet the top rib quite closely. The ribs are soldered and not infrequently, some flux has been trapped, resuling in rusting later down the road.

If that's the case, you would not want to weld. The rib should be removed and reset. Make sure the other ribs are solid before re- rust bluing.

If you trust your buddies welding, get some
3 1/2% Nickel rod from Brownells. I have used it for all sorts of pistol welding and have never had it blue different than the parent metal. I Tig a lot and its great stuff.






I have had no problem with it hot blueing. I don't know about rust blueing though. I would recommend MAX pre and post flow on the weld though.