Trying a reweld build

[turbosc20]

I bought these cut receiver from apex. I'm gonna try reweld the rear section of the receiver. Already welded the 3rd pin hole.

 

[Fodder4Thought]

Nice. Keep us updated!

 

[turbosc20]

some welding and grinding

 

[hvymax]

That looks like undercut/underfill after grinding. I see what you did to prevent burnthrough/welding to backer but you need to be sure your welds are tied in thoroughly or you might be producing a "widowmaker". Of course after you get it welded you will need to heat treat and temper. John B QC1 CWI

 

[Markp]

That looks like undercut/underfill after grinding. I see what you did to prevent burnthrough/welding to backer but you need to be sure your welds are tied in thoroughly or you might be producing a "widowmaker". Of course after you get it welded you will need to heat treat and temper. John B QC1 CWI

While the AK receiver doesn't take that much punishment and I doubt it would be a widowmaker, longevity of the receiver might be a concern. The welding would be better if you had used a filler piece and welded that in, instead of trying to bridge the gap. TIG welding would also improve the quality of the weld and rid it of some of the obvious porosity.

Mark

 

[turbosc20]

This is my concern as well. I was thinking about cutting it back in half where I welded with a saw and fixing all the welds on the inside and then use a thicker welder wire. Is flux core any good? I'm currently using mig .025

 

[carryaglock]

PM SENT!

 

[rob-cubed]

Nice! There's some good experience over on The AK Forum on rewelds... way outta my league but keep posting your progress!

 

[hvymax]

This is my concern as well. I was thinking about cutting it back in half where I welded with a saw and fixing all the welds on the inside and then use a thicker welder wire. Is flux core any good? I'm currently using mig .025

For crappy grade mild steel flux core is fine. You will want to anneal the whole thing afterwards so the steel will be evenly soft and unlikely to crack but probably will affect longevity. If you share my concern that you may not have produced one contiguous piece of metal you may want to recut and if considering filler pieces true up your ends to ease fitup. Remember you need thorough penetration and tie in regardless and unless you can match alloys you are probably best off annealing.

 

[Markp]

This is my concern as well. I was thinking about cutting it back in half where I welded with a saw and fixing all the welds on the inside and then use a thicker welder wire. Is flux core any good? I'm currently using mig .025

Flux core is crap...

MIG is ok, but you are trying to fill in far too much gap, you would be far better off if you had a second receiver to use for filler material, or at least order some 4130 steel of the same thickness. Standard ER70 wire/rod should be fine.

You don't want to anneal it, you want to heat treat the entire receiver properly,quench it, then relieve it... 400 degrees for 45 mins or so, and allow to air cool SLOWLY! Stress relieving and annealing are two different things, to really make hardened steel "soft" you need temps above 700 degrees C and perhaps as high as 900 degrees C depending on the carbon content. Unless you are planning on shooting this alot, stress relieving would probably be sufficient given the thickness of the steel on milled receivers.

 

[mbenz85]

Flux core is crap...

+1

I would seriously look into switching over to shielding gas for your MIG set up. A bottle of 75% argon and 25% CO2 blend will greatly improve your weld. You should get a much cleaner weld. The .25 wire is a good choice for avoiding burn through and too much weld on thinner material. I would avoid bridging that big of a gap with just weld. As mentioned previously filler pieces would be a better approach. I have not worked on a receiver before so good luck and keep us posted!

 

[Jerry M]

Aren't the cut AK receivers machineguns??? If so, stop what you are doing. If I am wrong, I'll apologize now.

Jerry

 

[turbosc20]

It's considered scrap metal.

 

[Markp]

Aren't the cut AK receivers machineguns??? If so, stop what you are doing. If I am wrong, I'll apologize now.

Jerry

Thankfully, they are scrap metal as noted above... additionally they count as a US part for 922(r) once rewelded.

Mark

 

[aquaman]

how did this turn out?

 

[armed ferret]

how did this turn out?

well it's been 2 years, if an update hasn't been posted, i wouldn't hold out hope.

 

[turbosc20]

Wow I forgot all about that project.

I warped the metal on one side and ran out of mig gas so I put it on the back burner.