Thread: Receiver welding needed!

Cheers for that guys! I'll hit them up Kotuku


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AR forged receivers are 7075 aluminium I think. 7075 aluminium is generally considered to be un weldable by arc welding (tig). It stress and corrosion cracks

If this was a normal bolt action you would drill and tap the receiver to fit a rail. Personally I would just buy a new upper but welding would be my last option.

Originally Posted by MassiveAttack

If this was a normal bolt action you would drill and tap the receiver to fit a rail. Personally I would just buy a new upper but welding would be my last option.

A pity that this has a lot less material to tap into compared to any bolt gun I have seen, and the whole alloy thing v steel.

I'm very interested in how the op gets on


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My suggestion is either chuck it, and get an upper with a rail, or...

Get a cheap "airsoft handguard" off aliexpress (such as http://s.aliexpress.com/NjYBRzE3 - search for 'ar15 handguard'), mount that to the front of the upper and use a one-piece scope mount like this (http://s.aliexpress.com/6RvQVvEn) to span the picatinny rail on the handguard AND the one you're wanting to fix to the upper. That should act as a jig to keep both rails aligned while you figure out how to permanently attach the rail to the butchered upper.

Use epoxy (I'd use Devcon or some other metal-filled epoxy) to bond rail to upper, and wait for it to cure before drilling, tapping and fastening with screws. I imagine there will be a gap between the rail and the upper that you'll need to fill with the epoxy. If you drill/tap before the epoxy is cured, you'll end up oozing epoxy everywhere.

Or, just chuck it and get a railed upper.

I'd buy a new upper. Failing that option I'd braze it with these. I have them in the garage and they work quite well.

10 Fluxless Aluminum Repair Rods & Bonus S/S Brush | Trade Me

I would not be putting any heat into any aluminium firearm part unless.
A you know exactly what grade it is and.
B you have it stress relieved then heat treated.

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Originally Posted by veitnamcam

I would not be putting any heat into any aluminium firearm part unless.
A you know exactly what grade it is and.
B you have it stress relieved then heat treated.

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The only good thing is that a ar upper contains no load on firing so no safety issues involved


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so I gave him a had and took this on. This is what I came up with.
http://www.nzhuntingandshooting.co.n...75/#post478798