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Old 02-12-2013, 9:59 PM
submaniac submaniac is offline
Join Date: Jul 2007
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Default Those Durafix aluminum brazing sticks really do work on ARs/M16's

Just thought I would share this in case anyone with an AR ever needed metal repair. Those brazing durafix or whatever aluminum brazing sticks really do work. I thought I would just share my experience on it.

This is what I started with on the m16 project

This is when I first brazed on the magazine well on it.

Notice that it is gray and frankly, looks like a mess. After the braze sits for a while it turns gray like that. If you polish it, or run it over with a wire wheel (which is what I did here), it shines up.

I purposely left the seam think and kind of sloppy. The deal is that when you braze one part of the receiver, it heats up the entire receiver which may make what you just put together want to melt a part. The way to fix that is just to make the "weld" thick, so when you heat another part of the receiver it won't melt.

Once everything is put together, I will grind it down.

I tried grinding down just a portion with the sandpaper thingy on a dremel to demonstrate what I am talking about

It really does grind smoothly so that I can't tell where the "weld" begins and where the original metal begins. Once this is together, I have no doubt that I could get it to the point where no one could tell by visual that it's been put back together.

I was screwing around with the "weld" on the receiver and other things I put together. That stuff is actually pretty strong. I think it is probably just as strong as the original aluminum, if not stronger. Things I've put together with it, I can't pull it apart.

The stuff is more elastic than aluminum. Like on the aluminum of a reciever, if you try and bend it, it will crack. The brazing stuff you can actually bend it (to some extent or another).

I had problems using it at first. I had stripped off the anodizing with lye. When I first tried using the braze it was heating up, but just not sticking. I had to use the dremel with the sandpaper wheel to take off a top level of the receiver surfact in order to get it to stick. I think there must be some anodizing or oxidation on the top which prevents it from sticking. It usually recommended to use a stainless steel brush prior to brazing, but that's still not enough. You have to remove a top layer of aluminum to be able for this stuff to stick. And it has to be hot in order to stick. But once it does stick, it does really work as advertised.

It is a little sloppy to use however. It does liquify easily so instead of sticking together it has a tendancy of liquifying and spreading all over the place. You have to get used to it to really be able to control it.

I put on one side of the magwell so I needed it in place to align the take down pins with the front and back. The magazine test fits into the repaired side of the magwell. And with the rear clamped in place, the rear lines up as well.

I am also using a spare side from another demilled receiver to align the holes.

I can't attach the rear portion of the receiver with the buffer tube until the holes for the autosear are welded shut (no braze will not be good enough for that). So it may have to wait until that is done.
Many thanks to the AK-Build team...California's version of Khyber pass.
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