how hard would this be to reweld... saw cut

[sharmanajusmc]

I don't have any pics at the moment but I have a saw cut mg34 receiver that I want to re weld, the problem is that the cuts themselves are about 4mm thick. all the directions for these I've seen is where two or more receivers are squared off and cut about flush then welded together, looks like this will need a 4mm fill with weld to get to proper specs. My question is am I likely to ruin this awesome reciever set by trying to do that much filling in?

[sharmanajusmc]

heres a pic

[CaptMax]

This all depends on your skill level and your welder. I've used a Miller SyncrowaveTIG welder and filled larger gaps than that before. Use a good jig and take your time. it can be done.
CaptMax

[ChrisPCook]

Not bad, but if it were me I'd try to get some small receiver scrap bits from someone here on the forum, etc...... wedge 'em in tight on the jig and weld em in, bevel them for good weld penetration....it can be a little tedious grinding down and fitting in the filler pieces, but IMO it's worth it... MAKE SURE YOU HAVE A GOOD JIG AND IT"S TIGHT....also double check the dimensions....there's a sticky on the saved threads of the 34 receiver dimensions....Chris...

[sharmanajusmc]

thanks for the reply CaptMax I appreciate it, with doing a fill this big is there anything I should keep in mind or any tips you or anyone else can give me? I'd say I'm not the best welder

[CaptMax]

I use an aluminum jig with copper backers. As someone previously said, bevel the edges to get maximum penetration.
Start at the corners and build up the edges until they meet, jump around from one side to the other never staying in one spot too long. Don't be in a rush! Double check all measurements as you go and allow a few thousandths for shrinkage. This should help you out. That is a nice kit, I saw it for sale too.
CaptMax
Ps. Don't be upset if you have to cut it apart and re-weld a couple times, it happens to us all one time or another.

[sharmanajusmc]

ok so the jig to get would that be the one that pirate has or?

[oakrodent]

I have filled larger gaps than that on some of my builds using a Mig Welder. It is possible. First you need to be a good welder to have safe/ strong welds with good penetration and fill. Second, you need a very good jig that has excellent heat displacement. I make all my jigs out of solid brass. Once you done welding you can't remove the jig. I let it sit for half a day to cool and then the last hour it sits in a bucket of ice water. The brass will expand and shrink more than the steel. The jig usually slides out of the receiver with very nice flat welds on the inside surfaces. Third, for a gap that large you really have to correct on your measurements and have external braces to stop the welds from contracting while your welding. I have built really large / thick walled receivers and very thin walled receiver with excellent results. No warping or shrinking. But just keep in mind. It's just steel, if you mess up you can always cut it back apart or fill it in. Just don't give it too much heat or use a cheap filler (wire) this can cause the steel to get brittle. So just don't be cheap on the filler. Just my 2 cents

[sharmanajusmc]

the jig that pirate sell on projectguns, will that work for this? or do i need something special since there is that much fill being needed?

[Bil]

Personally,I would use something else.Pirates jig would leave too much space for extra weld to get inside.Another thought-if you didn't reweld by filling,I think I would use bigger filler pieces,less heat in one spot.JMO. ---bil

[sharmanajusmc]

so where would I find another jig, is there someone on the forum that has these?

[Taurus454]

You could TIG weld it very easily. I would use a 4 ceramic, .040 tungsten bit, and 70 psi 1/16 inch filler rod. I use a tungsten bit sharpener and don't hand sharpen the bits. Be sure to set the AMP low probably 30-40 range to avoid burn through. Once you start you can adjust AMPs based on how the welding is going.

Any questions, give me a shout and I can give you more details. Always glad to help if I can.

Tom