Best way to fix this?

[StephenWhoDat]

I have a 3rd Gen with a crack in the frame under the grip. I still have the small piece that is broken off. Can this be welded or is there a better option for fixing something like this? Or should I attempt to sell "as is" to someone who can fix and who wants a 3953 since I have three of them? Thoughts?

 

[Muley Gil]

It can be welded. Back in the '90s, I dropped an aluminum 1911 frame. Of course, it was right where the mainspring housing retaining pin went. i tried to straighten it and it broke off. Took it to a shop and had it welded back on.

 

[cherrypointmarine]

Contact BMCM and ask him . He knows someone that does micro-welding . He posted about it in a thread of his about a 1066 that he cleaned up .

 

[VictorLouis]

Knowing how the grips mount, and what is stressed....it may not be a functional risk. Obviously, you'd want to disclose it on a sale if you go that route.

 

[chief38]

Assuming it is Aluminum (not very familiar with this model) you would need to bring it to someone that has a lot of experience welding Aluminum. Aluminum is a bit trickier to weld than steel. Once welded and trimmed back to original spec's, the finish would have to be repaired - but that is something you could attempt yourself.

 

[steelslaver]

If that was my gun I would repair it, but NOT by just welding back on the busted part. I would make a part about an 1" or more long of the same thickens and with the hole in it. Then machine off a matching spot on the frame So the hole was properly located. Bevel the frame and repair part and then weld in place. This would give a much larger weld area to share the load and the weld area on the bottom of the frame is non critical and only holds the grips and magazine in place.

Because.

Although you can weld the aluminum used for most gun parts, unlike steel or many other mild aluminums it will never be anywhere near full strength. The weld's heat affected zone will always be brittle. Does not matter if it is tig, mig or micro welded this will remain true. Micro welding is probably best because of the smaller heat effected zone so maybe on a none critical part, but I would never ever trust it in a critical area. Post weld HT will improve it somewhat. Notice how airplane are riveted and not welded thats because they use the same or similar aluminum alloys as gun frames. High strength heat treatable alloys.
Aluminum gun frames are usually 7075 or 6160

From the AWS (American Welding Society)

The 7XXX alloys are the ones that usually trip designers up. They are the very high strength Al-Zn or Al-Zn-Mg-Cu alloys that are often used in aerospace fabrication, and are supplied in the form of sheet, plate, forgings, and bar, as well as extrusions. With the few exceptions noted below, the designer should assume that the 7XXX alloys are non-weldable. The most common of these alloys is 7075, which should never be welded for structural applications. In addition, these alloys often suffer from poor corrosion performance in many environments.

A few of the 7XXX series defy the general rule and are weldable. These are alloys 7003 and 7005, which are often seen as extrusions, and 7039, which is most often seen as sheet or plate. (and used in bike frames)

6061 is more weldable but mostly only done in lap joints etc, because the welds are prone to the same cracking in the HAZ. If weld is where 2 piece are butted up to each other and the area between them filled with filler metal and that would include a crack, there is no other support area like when a lap joint is used to spread out the HAZ and increase the support area

 

[diyj98]

Although you can weld the aluminum used for most gun parts, unlike steel or many other aluminum it will never be anywhere near full strength.

I agree. Many steels won't be the full strength as well, but especially so for aluminum. I'm not sure I trust a welded aluminum frame if it was in a critcal area, but I have an aluminum tree stand that broke probably ten years ago. I knew the welder really knew his stuff that I took it to. It's still holding my 200 plus pounds every season after all these years.

 

[torizus]

Having that "small piece that is broken off" is a big plus for you, it may be worth looking into.
Worse that can happen is the hammer stops hammering.
Certainly wouldn't ever be a self defense grade firearm but work great for target stuff.

 

[Mrnurse]

7074 7075 is way tricky to weld in the aviation industry but is done daily by master welders at American. Airlines have Amazing Machine shops and Welding shops building and repairing some complex aircraft parts and ahhh hummm some non aviation parts.

 

[steelslaver]

They may weld 7075, but they are not doing it on butt welds on critical parts. I know several really really good aluminum welders and my brother is an certified welding inspector. The problem isn't the weld itself, but it what happens to the alloy in the area surrounding it affected by the heat. This area WILL become more brittle and the grain structure in theses areas the part will cause them to NOT be anywhere near 100% strength. In large sections with sufficient amounts of redundant load bearing you can get away with it. But, it will never ever be anywhere near 100% of its strength. Even the aircraft industry has to adhere to AWS standards.

They are working on a process to get a 100% strength weld on this aluminum thought. It involves titanium in the filler metal.

Welding many other structural aluminums is easy and I do it all the time and never worry about it

But like I said on that part I would not just weld the 2 little spots to hold the tab back on. I would replace a larger section and make the replacement piece with a the hole in it. Much stronger than a couple tiny welds that would have lots of heat affected zone compared to their section size.

That is the way you fix broken pieces of high alloy aluminum with weld. Make the weld in the best possible location to give it redundant strength and keep the weld as far as possible from the critical area.

That is why NOBODY welds up AR frames in critical areas or the crack an alloy revolver under the barrel etc etc. No way do do it in a non critical area, or an area with enough redundant strength to make up for the problems in the HAZ. You could make the weld, but it will fail.