Mig Welding a barrel

Brambles

Brambles

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Will mig welding on a barrel stress it or hurt it in any way?

I have a rear Iron sight dovetail that I want to fill. I'll use a low setting since its not structural and keep the welds small, and take my time not to overheat the metal.

I see that people weld up rust pits on actions, although smaller than the dovetail the result is the same.

Is this an accepted method of closing up a dovetail or is it bubba'ing the rifle?
I don't want to bubba this rifle but if a gunsmith is going to do the same thing then It's something I can do, I'm more than capable with my welder.

Thanks

Brambles
 
i would buy a dovetail blank and install instead of welding which can cause changes to the metal. The blank looks kinda classy.
 
A blank fitted in and draw filed to fit the barrel contour and then lightly welded in any gaps, followed by draw filing, polishing and bluing would work... too much to fill in by welding alone in my opinion. Sometime just a blank filed down and finished looks good without welding.
 
AFAIK, cosmetic restoration welding done on firearms is usually done with TIG. You would certainly want to use an anti-scale compound in the bore.
Personally, I think a dovetail filler is a better way to go.
That would be a standard 3/8" filler. Brownells sells them, they are not difficult to make.
Just a comment about PH barrels. I have found them to be harder than others. I would be very leary about welding on one.
 
The oldtimers that I have read, say that there is the possibility of forming a tight spot on the bore, from the stresses of the heat and cool of welding.

The recommendation was to avoid it if possible, or to do it prior to relining a barrel, if it was being done to erase historically inaccurate work.

If it is a stock dovetail that might be of use in the future, I'd go with the filler piece and leave it at that.

Yours, so it's your call.

Cheers
Trev
 
Guess I'll break out the file and barstock...or take it to gramps and make one on the milling machine, gotta learn how to use it sooner or later.

First I have to cut and crown the barrel, I'll shoot it before I go to the trouble of filling the dovetail, if it doesn't shoot, I'll scrap the barrel and put another one on, but I can't see it not shooting half decent.

Thanks guys
 
"TIG also produces a welding heat is that is confined between the weld and base metal at the point of fusion and produces a narrow heat affected zone."
This was quoted from a popular welding site with permission.

Tig is the way to go!
 
Tig does have more/better heat control, but it is not necessary in this case, and mig or tig would make too much heat, if you were to do it all at once.


use your mig, stack tacks, and sit there with a wet rag of cold water, tack or two and cool, constantly cool it again and again, and it wont affect the metal too much.
 
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"...where does a guy get one..." Brownell's sells them according to the size of the dovetail. Welding isn't a good idea.
 
In welding up 4140 the concern is the hardness caused by the heating and rapid cooling at the interface of the weld and base metal. If this can be confined to the surface with a MIG weld, it would likely be OK. Otherwise, the barrel has to be pre-heated (about 900 F should do) and post heated (hotter. about 1100F). Otherwise, the base metal becomes very hard and brittle and may fail. In truth, I don't like welding on a barrel regardless. Regards, Bill.
 
Brambles said:
Will mig welding on a barrel stress it or hurt it in any way?

I have a rear Iron sight dovetail that I want to fill. I'll use a low setting since its not structural and keep the welds small, and take my time not to overheat the metal.

I see that people weld up rust pits on actions, although smaller than the dovetail the result is the same.

Is this an accepted method of closing up a dovetail or is it bubba'ing the rifle?
I don't want to bubba this rifle but if a gunsmith is going to do the same thing then It's something I can do, I'm more than capable with my welder.

Thanks

Brambles
Click to expand...
any kind of welding on a barrel or any thing will warp ,
period. even a spot weld will warp a barrel. a dovetail
blank is the way to go. use 290 locketite which is the
penertrating kind for assembled parts. u can make a dovetail blank in 5 min with a hacksaw and file. ask any welder.
 
Hey I can maybe help you with this as I'm a professional welder but not a gunsmith.

Gun barrels have a certain temper and a certain molecular stress pattern/design. Just like if you want to temper a tool you heat it to glow then fast quench it in oil. When your barrel is drawn (before machining) they do indead do heat treat/temper your barrel (though in a process MUCH MUCH more engineered and controlled then tempering a punch or someother tool). So when you take a tig and say hit it with 2200 celcius heat (just to round the corners) you are in effect changing the molecular pattern and stress designs (NOT a good idea). I've seen lots of work done on barrels (I.E m-14 supermatch the factory brazes something on the gas valve.) Brazing can be an effective way to fill a hole but you have a different finish now (shinny if polished and green if you don't). but it happens at significantly lower temperature and will not melt steel.

hope that helps.

cheers,

aninchlow
 
Thanks for the replies Ya'll, I'll spare the barrel the welding and fab up a dovetail insert.

So far its pretty unanimous that it isn't a good practice to weld a barrel, and since I'm Anit-bubba. I'm not gonna do it..


Thanks

Brambles
 
welding has its place but, NOT A RIFLE - BAD BAD IDEA. You use a mig to fix your car or to build a tool box, NOT TO FIX A RIFLE!!!!!!!!!!

Life may not be fun some days but not worth killing yourself. (do not weld on a gun.)
 
Welding is done on guns all the time. There is absolutely nothing wrong with welding, if it is appropriate. Bolt handle alterations are done regularly. FWIW Winchester used electrical spot welding to attach front sight ramps on post-64 M94s. Most sophisticated job I've seen involved two Mauser actions. They were cut, parts swapped, and .22-.250 and magnum length actions resulted after being TIG welded back together. Receivers, bolts and magazines were welded.
 
tiriaq said:
Welding is done on guns all the time. There is absolutely nothing wrong with welding, if it is appropriate. Bolt handle alterations are done regularly. FWIW Winchester used electrical spot welding to attach front sight ramps on post-64 M94s. Most sophisticated job I've seen involved two Mauser actions. They were cut, parts swapped, and .22-.250 and magnum length actions resulted after being TIG welded back together. Receivers, bolts and magazines were welded.
Click to expand...

WOOHOO! yep. don't get me wrong there mister. There are places you can weld on a gun, but NOT the barrel. A barrel gets its strength and its accuracy from uniformity. WOULD welding a dovetail mount to fill it in hurt the barrell? = PROBABLY NOT..... BUT it will change the metalurigic & molecular spec/design/composition of the barrel = BAD = potential saftey & [more importantly ;)] accuracy.

Welding handles on bolts is not going to affect the actual firing of the gun. In fact my handle on one of my pin drivers is welded on then machined.

Spot welding is also VERY different. When you weld a horizontal line along a high pressure pipe you need to do quite a few things to "reset" the way the molecules sit (take the proverbial twist out of them). Spot welding is used because it has such a low IMPACT on the metal around there is no great heating effect because the temperature is lower and for less time. (especially on a large mass like the rear dovetail.)

Doing the TIG dance on a couple of actions isn't a big deal either (as long as the work is clean and machines out fine). The only real "stressed - under fire" part is the bolt head where it locks on the lugs. (or so I believe) so you could weld a flag pole to the actual bolt if you wanted it wouldn't change the "functioning" of the gun..... but you would look like a dork :D.

Course I know metallurgy not gunsmithing so take things I post with a HUGe Lump of Salt - and you did say "where appropriate."

cheers,
 
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