New UZI builder, welding without a jig

[Eth727]

Any tips or suggestions for a new uzi builder that's going to be welding an Uzi receiver without a jig?
Thanks

 

[root]

Use thick or real heavy copper or brass bars for backing aluminum will work if that all you have it helps to prevent warping and blow through.
Tack everything far apart and go slow jumping around to prevent warping.
Use tig if you have it Mig and gas 2nd wire core 3rd and stick last.
Don't use them all that's the order for best welding finish.

You can use the top cover barrel and grip to get close setting without measurements. You will still need to measure though.
They are not a hard gun to build.

Have fun and post pix
Rich

 

[Eth727]

When I butt weld the front or rear pieces of the receiver do I leave a small gap or metal on metal. Where do I get the copper? Home Depot , ACE hardware.
Thanks

 

[dgleavitt]

Copper bars are best had from eBay in my experience

 

[slimshady]

When I butt weld the front or rear pieces of the receiver do I leave a small gap or metal on metal. Where do I get the copper? Home Depot , ACE hardware.
Thanks

Are you going to TIG or MIG? Typically, with MIG you want a very narrow gap so the weld can penetrate fully. The wire is basically shot into the gap and melts both sides together into the weld bead. TIG, OTOH, you usually butt them together with no gap as the TIG torch arc will go to one side or the other of the gap and it's hard to get the puddle started on both sides.

Copper can be bought off Ebay, but if you have a local scrap metal dealer they often have what you need for a little above scrap prices.

 

[Eth727]

I'm using a harbor fright fluxcore mig welder.

 

[root]

Do as slimshady said then and join butt the metal together.
Then cover your weld area with a type of masking tape. The thin 3/4 or 1/2inch wide stuff and spray anti spatter or Pam cooking spray on the rest of the gun. Remove tape and weld the clean seam.

The anti spatter stuff will help keep the flux spatter from sticking all over and save with cleanup.

Just degrease the parts between taping so the weld will stick to new areas when welding.
Cheap brake cleaner can be used to degrease.

Rich

 

[Eth727]

How about the ejector rivet? How do I bash that?

 

[slimshady]

Take a large bolt, file/grind it flat on the end and then drilll a divot in it approximately the size of the rivet head. Depth should allow the pre-formed head to sit in it just shy of flush with the bottom edge of the head. Make a second one. Clamp one vertical in your vise, assemble the ejector and rivet to the receiver and set the pre-formed head in the divot of the vertical bolt. Have someone hold everything level and use the second one with a hammer to smash the rivet. Make sure nothing has shifted between blows. If you don't care about looks, just smashing the bottom side flat with a big punch works too.

 

[Eth727]

Thanks I will give it a try.

 

[Eth727]

So I installed the ejector and grip mount. I did a test fit but the trigger doesn't work. When it's out of the receiver the trigger releases the hammer. It doensnt work in the receiver.

 

[root]

sear pad is probably hitting the receiver or repair channel.
May have to open the sear pad hole a bit with a small file.


Rich

 

[Eth727]

Oh okay I figured it out. I extended the sears when I put it through the holes. Now it functions. Thanks

 

[painted black]

Oh okay I figured it out. I extended the sears when I put it through the holes. Now it functions. Thanks

Hello, I wanted to follow up on your build. I am working on one and have not welded the fron Trion yet so I wanted to see how you kept the barrel, feed ramp and reciever aligned? I know lot of people use the dust cover for keeping the correct length. I was also hoping someone may have instructions or experience making an alignment bar or welding jig.

 

[thomas]

Did any of you guys have an issue with contamination even after dipping and sandblasting? I did some test TIG welds on some 14ga sheet metal which came out perfectly and tried the receiver with a TIGHT backing bar and had a ton of porosity. There was no oil smoke to speak of, but there was a ton of brown rusty-looking filth around the welds. Zinc maybe?

 

[ericthered]

If set the repair section uside down on a flat block or table, can align the demilled trunion flat with it. Obviously will have to have the sight ears hanging free so its resting on just the part the top cover fits on. Should be able to get it level on that axis then.