"Precision" Gunsmith Welding

McMillen Precision · Thu Apr 09, 2015 11:27 am

Hey Everyone, im new here and am in need of some experienced advice. I have recently picked up welding to help my gunsmithing business out and soon learned it has become a necessity and extremely addicting. I digress. The point is, I can lay beads all day long, but when it comes to small TIG welds I have issues. I am running a small 165 amp tig machine with 1/16th 2% thoriated and 100% argon. From everything I have read, 1/16th should be ran between 50-90 amps and most of the time I really have no issues until it comes to welding bolt handles onto bolt bodies. I have many requests for custom handles on the Mosin Nagants, and while the manufacture of the handle is simple, the welding is what gets me. I have cleaned the metal, gave it an acetone bath, and still I have issues. This is a 3/8 inch shaft, sitting on a mild carbon steel body. Any tips on how I can make a good solid weld around the base of the bolt? Any help would be appreciated.

AndersK · Thu Apr 09, 2015 4:38 pm

Hi and welcome

What material are you trying to weld and what issues do you face?

It doesnt look like you have cleaned the mill scale off that rod.
You can weld it but it will be better if you clean it with a flap wheel first.

MinnesotaDave · Thu Apr 09, 2015 5:02 pm

McMillen Precision wrote:Hey Everyone, im new here and am in need of some experienced advice. I have recently picked up welding to help my gunsmithing business out and soon learned it has become a necessity and extremely addicting. I digress. The point is, I can lay beads all day long, but when it comes to small TIG welds I have issues. I am running a small 165 amp tig machine with 1/16th 2% thoriated and 100% argon. From everything I have read, 1/16th should be ran between 50-90 amps and most of the time I really have no issues until it comes to welding bolt handles onto bolt bodies. I have many requests for custom handles on the Mosin Nagants, and while the manufacture of the handle is simple, the welding is what gets me. I have cleaned the metal, gave it an acetone bath, and still I have issues. This is a 3/8 inch shaft, sitting on a mild carbon steel body. Any tips on how I can make a good solid weld around the base of the bolt? Any help would be appreciated.

First - only weld bright clean metal with tig - you probably knew that.

Second - welding beads is not practice for welding bolt handles - you have to practice welding small round objects onto flat objects.

Do this over and over until it's perfect - then weld bolt handles.
I would not weld this in the 50-90 amp range - too cold and slow.

Anytime you weld a new size material, in a new configuration or position - practice exactly that first on scrap.

After a few hundred hours experience you will only need a quick refresher weld before starting.
I always weld a test piece before the real thing unless I've done the exact same thing recently.

McMillen Precision · Thu Apr 09, 2015 7:05 pm

Well, what im more concerned with, is the amount of heat build up on the bolt body. The body is made of low, to mild carbon steel. The picture that i provided is a terrible picture prior to welding. When i did attempt it, it was clean and bright. The bolt handle itself is made of 3/8 hot rolled steel. Sorry that i didnt clarify that. If 50-90 is to low, what do you recommend for practicing the technique? Im sorry all the questions! im extremely new at this and the amount of weldind i do is very limited and very small haha.

Braehill · Thu Apr 09, 2015 7:56 pm

You haven't mentioned what filler rod you're using. I would personally try first with an ER70S6 rod and if I got porosity I would try a 309L stainless rod. Not sure if the stainless affects blueing though. Low and slow puts more heat into the part as the others have said, so you need to get to where you can get in and get it welded and get out.

Get some hot rolled 3/4" rod and some HR 3/8" rod and practice that joint until you can weld it well.

I'm at work and most images are blocked so I can't see your welds, sorry.

Len

Thu Apr 09, 2015 8:24 pm

McMillen Precision wrote:Well, what im more concerned with, is the amount of heat build up on the bolt body. The body is made of low, to mild carbon steel. The picture that i provided is a terrible picture prior to welding. When i did attempt it, it was clean and bright. The bolt handle itself is made of 3/8 hot rolled steel. Sorry that i didnt clarify that. If 50-90 is to low, what do you recommend for practicing the technique? Im sorry all the questions! im extremely new at this and the amount of weldind i do is very limited and very small haha.

You are building heat in the part by welding at too low a current... Spending too much time getting the area you want to fuse "hot enough" gets everything hot.

The rulebook is a suggestion-book. You can do this with a 1/16 tungsten (and I would), but you should have your welder set at 150A. Get in, weld a short bit at high current, and get out. Short bursts of heat, and let it cool.

Patience, in all things.

Steve S

McMillen Precision · Thu Apr 09, 2015 8:36 pm

Thank you all so much! I'm heading out to the shop now to get some practice in! Thank you all again! I'll post pics soon!

LtBadd · Mon Apr 13, 2015 8:15 pm

McMillen Precision wrote:Thank you all so much! I'm heading out to the shop now to get some practice in! Thank you all again! I'll post pics soon!

Let's see some updated pics, as Steve said a 1/16" 2% thoriated tungsten will handle up to 150 amps, if you're welding a lot near the upper limit (of a 1/16" tung) then move to a 3/32" tungsten

pgk · Tue Apr 14, 2015 10:20 am

Couldn't you just braze it? Less heat input...

exnailpounder · Tue Apr 14, 2015 5:27 pm

pgk wrote:Couldn't you just braze it? Less heat input...

Gunsmiths are like machinists...picky picky picky and they need to be. Guns are precision instruments and need to be smithed as such. Who would be happy to take a prized weapon to a smith and get it back with a brazed on part? I don't know about anyone else but I would be pissed.

LtBadd · Tue Apr 14, 2015 7:51 pm

exnailpounder wrote:
pgk wrote:Couldn't you just braze it? Less heat input...
Gunsmiths are like machinists...picky picky picky and they need to be. Guns are precision instruments and need to be smithed as such. Who would be happy to take a prized weapon to a smith and get it back with a brazed on part? I don't know about anyone else but I would be pissed.

Well I can't say I know anything about gun smithing, however to even consider a brazed joint the mating connections would need to be a machined fit to assure a proper braze

echosixmike · Wed Apr 15, 2015 7:38 am

Bolt handles are typically silver soldered (brazed) on, but this design won't work for brazing IMO. S/F....Ken M

McMillen Precision · Thu Apr 16, 2015 10:41 am

Alright, well as for what was mentioned about brazing. It does have its uses, and can provide some use in the shop. However, most times for us it comes down to using silver solder for things like sight ramps and sling barrel rings for safari rifles. Low heat, almost no torque applications. Tig welding has opened my eyes to a lot of advantages in my business. I listened to everyone's advice and ran it at 150 amps for short durations and it turned out results MUCH better. I appreciate the advice because it did pay off. Clean up was a breeze and gave a much stronger weld than I could have ever imagined! I cant wait to get more TIG jobs and bolt handle builds!

Prior To Clean up

Finished Bolt Handle prior to paint

LtBadd · Thu Apr 16, 2015 7:04 pm

McMillen Precision wrote:Alright, well as for what was mentioned about brazing. It does have its uses, and can provide some use in the shop. However, most times for us it comes down to using silver solder for things like sight ramps and sling barrel rings for safari rifles. Low heat, almost no torque applications. Tig welding has opened my eyes to a lot of advantages in my business. I listened to everyone's advice and ran it at 150 amps for short durations and it turned out results MUCH better. I appreciate the advice because it did pay off. Clean up was a breeze and gave a much stronger weld than I could have ever imagined! I cant wait to get more TIG jobs and bolt handle builds!

Prior To Clean up

Finished Bolt Handle prior to paint

That's good news, and thanks for the photo's. That first pic reminded me of a job I had welding a shaft onto a putter, the form was somewhat similar.