Tig welding on the rear portion of a rifle receiver..

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Wanting to ask some of you guys as I've never done it myself..  I know it can be done and know it has been done to this specific rifle platform.. I feel confident I can weld it myself, but want to be more certain of my process..  I havent talked to my gunsmith buddy yet, but plan on before I do this, just to see what he thinks. The rifle is an old 1942 Soviet Mosin Nagant which shoots a 7.62x54r cartridge, just a tad bigger than a .308 by like .003... I suspect the material the receiver is made of is equivalent to 4140 prehard, no one knows for certain..  I plan to heat the receiver up to about 200 degrees then weld it with er70s6, then set the receiver back in the oven to slow cool to 200deg after welding, then take it down to like 150 for an hour or so, then just turn the oven off and let it set over night.. The area I'm wanting to weld is at the rear of the receiver over the top of the bolt, anyone familar with the rifle knows where I'm talking about...  I'll include pictures so you can get an idea.. The area where I'm looking to weld is a good ways from any crucial areas of the receiver, no where near the chamber or lugs.. these pictures are of unmodified recevers.. These pictures are of various modified receivers.. I'll include some more pictures in a following reply. tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:some more pictures of modified receiverstackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:I do some tig repair stuff for a gunsmith near me mostly on shotguns.I Tried using 70s 6 also and had cracking issues......Didn't pre heat or post heat so can't say if that would have fixed the cracking....BUT I did switch over to 308L  and the cracking stopped....309 might be better?The bluing had to be removed and I suspect that may have added to the problem.....Hope this helps....  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:I'ld call Eric. But he's been at ShotShow...http://www.youtube.com/user/Iraqvete...ch?query=mosinCity of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Originally Posted by tanglediverI'ld call Eric. But he's been at ShotShow...http://www.youtube.com/user/Iraqvete...ch?query=mosin
Reply:That mod is a "bridge" for scope mounting ? Take a horizontal mill and mill a flat about 3/16 deep.Fit up a piece of cold roll to whatever height and contour you need and get some low temp silver solder from Brownells. No need for welding at all.Toss it in the bluing tank.Done.Bubble gumTooth pixDuct tapeBlack glueGBMF hammerScrew gun --bad battery (see above)
Reply:You can get a low temp melt solder from a gun smith supply.  No welding. Easy to return to stock.Hey~!! It's a hobby. It's not supposed to make sense~!!
Reply:I have a Hammerli 22 that broke the shell ejector, which is part of the main frame. my gunsmith used 309 and heat sink, no pre or post heating.  700 rounds later, all is fine.Lincoln SA 200Esab Caddy 160Thermal Arc 201TSMiller Dialarc HFI don't like making plans for the day because then the word "premeditated" gets thrown around the courtroom....
Reply:I  thought that you Brucer would know what is best and how to handle this ; and Im sure you still do. Silver braze but Im outa my leuge now.
Reply:im interested to see the outcome. only experience I have was welding the bolt handle on in a way that would clear my buddies scope. I was scared out of my mind but he still uses it. that was years ago but I believe I used a 70 series filler.bosses stuff:trailblazer 325maxstar 200my stuff:sa 200fronius transpocket 180100 amp Lincoln w/f97 f350 DITKevin
Reply:Originally Posted by dubl_tI have a Hammerli 22 that broke the shell ejector, which is part of the main frame. my gunsmith used 309 and heat sink, no pre or post heating.  700 rounds later, all is fine.
Reply:Here's what you use.http://www.brownells.com/gunsmith-to...r-prod584.aspxBubble gumTooth pixDuct tapeBlack glueGBMF hammerScrew gun --bad battery (see above)
Reply:Originally Posted by BurpeeHere's what you use.http://www.brownells.com/gunsmith-to...r-prod584.aspx
Reply:+1 for silver solder or brazing. I read once that brazing is every bit as strong as welding where high temps are not expected.Miller Multimatic 255
Reply:brucer,I don't know the answer to your question,but I'd go to the weapon's guild forum and or the militaryfirearms forum,those guys helped me allot!either you LIKE BACON or you're WRONG!!!! "There are three kinds of men.The ones that learn by readin'.The few who learn by observation.The rest of them have to pee on the electric fence for themselves"-Will Rogers
Reply:@ brucer - cool.  Chad Dixon, in SD.  www.longriflesinc.com/index.html.  Chad's a CNC wizard, outstanding rifle builder, and an awesome dude.  Recommend contacting Chad for a consult."Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:Originally Posted by BurpeeHere's what you use.http://www.brownells.com/gunsmith-to...r-prod584.aspx
Reply:Silver braze strength is around 110ksi, that is nearly as strong as normalized chrome-moly used in bicycle frames.
Reply:If your planning on bluing this, stainless won't take bluing and neither will silver solder. I think there are fillers available from some gun parts houses that will color match bluing on the rest of the gun. If your going for a cerakote or something like that then it doesn't matter
Reply:My opinion is do not pre-heat as that will change the characteristics of the steel where the locking lugs are.Just TIG it, keeping the heat localized in the rear (Heat Sink).I've had various surplus receivers modified by a Smith in Missouri over the years and that is the way he does them.
Reply:I've been told that Rockmont Tartan TIG filler can be blued.  I have a bit but haven't tried it.http://weldit.com/products/tartan-tig/"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder