I have an idea that I'd like to try that is my own stupid idea and I have the money to burn and I don't care if it's stupid or efficient or economical so we can get that out of the way.

I'd like to frankenstein weld some 6061 stuff to a lower for testing out a theory.  Having some trouble finding 6061 lowers and I know someone here knows exactly where to point me.

Thanks in advance!

5d tactical has 80's
Juggernaut
Gat Guns
Alex Pro


FYI: You can weld 7075.
Unless the thingies you want to weld to the lower are exclusively 6061, then I understand.

80 percent  Arms.
Gorilla Machining.
80lowers.com
80percents

*All 80 percent lowers.

If you're thinking of extending the magwell similar to an FAL, I tried that years ago, when I was swapping lead with a very well organized gang, and needed to reload without taking my eyes off the threat.  The only problem was that it worked only with GI mags and a few other mag designs.   Pmags and most other modern mags would not fit.  I wasn't trying to develop a product for mass production, just increase my chances of staying alive.   I used an ancient 20% lower that was apparently made from 1100 series aluminum, and it was so soft it began twisting at the pivot pin, eventually causing jams.   And the bare aluminum upper, that came with the lower, from a gunshow, was another factory reject.   The 1" reamer got loose and chewed up the insides.  Someone cleaned up most of the damage but the hole was so big the bcg rattled around and I got an eye full of back blast on every shot.

I have TIG welding experience, but when I tried welding 7075, it took a massive amount of amps and didn't look very professional.   My advice is to start with an 80% from a known seller, that will confirm it is 6061.

Good luck.   Looking forward to seeing your design.

Not if you want the weld to have any kind of strength.

Most rifle-use lowers see little force at all outside of the trigger/hammer pin forces and the bolt catch. A drop-in trigger solves a bunch of that.

John Norrell was very successful in welding lowers back together using 100% aluminum rod.

If you have TIG experience you should or now know 7075 is generally un-weldable unless you want a decoration.

https://blog.blackadvtech.com/why-is-welding-7075-aluminum-impossible

You have posted on here before (several years ago) some new technique that permits 7075 to be welded.  Something about TIG electrodes being inoculated with some other substance - carbides?

I can't remember.

I think I remember you posting something about that a few years back in one of the Let Every Man Be Armed threads.

I got a sample of those special rods, and had some test coupons welded up. Also used the common 6061 filler (5631?).
No immediate difference in strength or ductility between the two.

I went ahead and had some trigger and FCG holes welded up on some Armalite pattern AR10 lowers I messed up. I think I used the magic rods on one, and the regular crap on the other. Welded fine, but I don't have access to my materials testing lab any more, so.....no micrographs or grain samples.

I still have some of these sample 'magic filler rods' that supposedly allow one to weld 7071-T6, if anybody wants a couple. I hounded that company for over a year to get the sample. Be warned, they're Chinese, so who know what the hell they actually sent.

Metal-Li was the company, they're vacant from the web now.
This was the article that led me to them. The prof in the article connected me.
https://newatlas.com/welding-aa7075-aluminum-alloy/58449/

Edit, I found them, they're still in business
7075 welding rods

Oh, I did the research, and at that time everyone said it was unweldable.   Naturally, when I hear that, I just have to try it myself.   Lots of bullshit on the internet.  I used 7075 and 6061 and I think the rod was 4043.  It was a mess.   I kept cranking up the amps till I maxxed out the machine at 300 amps, which was enough to melt the protective liner on the TIG torch because I hadn't set up the coolant system yet.  Totally ruined a $200 set of torch cables/lines.

The alloys melted together, but it was just an experiment.  No immediate cracks but I did not put any kind of load on the piece.  I had no idea to the strength of the new piece so it hit the trash can.

Most billet lowers are 6061.  

My goto is a 5D, 80%

For reference.  On racing bikes back in the 90s, 6061 was welded by makers like Klein and Cannondale.  Both made great frames.  Cannondale ground their welds to hide the slop but Klein welders could lay a bead and finished looked like it was brazed.  

7075 frames were all bonded to Al lugs.  They didn't do well with many having galvanic corrosion and disbanding issues at the lugs.  6061 is easily welded by pros.

Yep.

Those threads were great, except most of the parts I bought/received were either defective or airsoft stuff.   Glad other recipients got better parts.

Calling my rifle a frankengun would have been a huge and undeserved compliment.  It was a pile of junk parts that had one malfunction after another.  Not anything anyone would have wanted in an actual firefight.   I needed something reliable that could hit a softball at 200 yrds.

Thousands of 7075 bicycle frames are TIG welded successfully every day.

The sheer number of 80 percent grafts in use should have put this debate to bed long ago.

Yes it can be welded. No, not everyone can pull it off.

Who welds 7075?  I haven't bought a metal bike in 20 years.

The tech paper from UCLA came out around 2019 about the 7075 nano tech welding. Very little has been fielded outside the lab since then and industry wise its still considered not weldable for any real use other than cosmetic or filling voids in molds.

I work in automotive and our processes included welding / joining aluminum frame sections and structural riveting.
I know of no industry that welds 7075 for any kind of commercial application other than some mold repair to fill voids.

I like trying new technology for old problems and one that sticks in my head was a "new" arc welding rod to stick weld aluminum. I asked our weld supplier about it and he grinned and said he would bring me a pound of rod to test. That shit burned like a Chinese firecracker with horrible green / yellow arc and fumes from the flux that would knock you down. Weld deposit looked like shit.

What manufacturer ?

Are you confusing 7075 with 7005 ????

Polestar/OEM and Huang Wei are 2 that OEM 7075-T6 fusion welded aluminum bike frames.

Stateside it just hasn't caught on unfortunately. Probably because many accept 7005 or titanium substitutes. That and it's difficult/damn near impossible to perform a cosmetically pleasing 7075 finish weld (like the majority of cyclists will expect on a $2-$3k frame set).

Titanium carbide.

"Thousands" may be an inaccurate statement, an actual estimate being difficult as anything China is guessology.