Welding or Brazing recommendations

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PK1

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I would appreciate some advice from those of you who have experience welding or brazing aluminum: I have made a side mount license plate for my motorcycle, and I am looking to assemble the pieces together. I would either need to weld the pieces together or braze them. I have made the small brackets for reinforcement otherwise vibration and wind forces can fatigue and brake the main bracket from the license plate holder. I have both a brand new mig welder with a spool gun, and a torch with aluminum brazing rods. Problem is, I have never welded anything nor brazed aliminum!

Brazing the main bracket to the license plate holder would be easy. I have machined a ~1mm groove in the plate so that bracket will stand on its own for either welding or brazing. I am trying to figure out how to fixture the two small reinforcement brackets to weld or braze. I suppose I could tack weld them in place and then weld, but brazing may be more complicated since heating the assembly up may melt the braze in other places while I work to braze the pieces in stages.

The main plate (largest piece) is 1/8" think (~3mm) and the brackets are 3/16" (~5mm). Any recommendations on the best approach considering I am a complete novice to both methods?

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Take it to a shop and have them tig it.

You can do it with a spool gun, but unless you have some experience working with it, its easier to make a mess than actually stick things together. You’ll also need a bottle of argon. Mig mix doesn’t work on aluminum. Makes a royal mess.

I find when I use my spool gun on my mig to do Al, I’ve got to hit it with a lot of amps and its hard to manage the puddle.
With tig, you dial in the amps you need and manage the puddle with the foot pedal. Much easier with tig than mig.

With small parts like you have, you really want tig to control the heat and not burn through or turn your parts into a puddle on the floor.

10 mins, tops, for a pro to burn your pieces together. I seen guys who tig for a living weld tin foil together. They’re that good with small, light parts.

Can’t help you with “brazing”. You’d likely need something like that “muggy weld” stuff because regular braze doesn’t work on aluminum. At least I’ve never had any luck with it. Makes a nice mess for me without sticking anything together. I think “muggy weld” is closer to a solder than a braze anyways.my understanding is that once you’ve started with “muggy weld”, you’re stuck with it as it doesn’t react to tig well (Too soft, takes heat fast and wets too much of the surface to get a good tig weld) Don’t quote me on that though…
 
Thank you both. I have an Argon tank - well an empty tank that I was planning on filling with Argon, but I think you are right about Tig welding.

I bought the mig welder a couple of months ago so that I had it on hand in case I ever needed it, but in hindsight I wish I had gotten an AC Tig instead. I could do everything with a Tig, but not the other way around...
 
MyLilMule said:
Like others have said, I would TIG that, not braze it.
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Yep, Tig it is. Question I need to answer is do I go buy a tig welder so that I have one for future use, or do I pay someone to do it for me. Hard to justify two welders when my welding work is at best minimal.

Purely for educational purposes, why would you not braze this?
 
since this is a “visible” part, I’d take it to a pro and have it tigged.

Then but yourself a tig box. Get something decent, not one of those 300-400 dollar things. Siggesting a box can take pages and pages of replies, so I won’t tey here other than say blue, red or green…as high an amperage as you can afford because Al takes a lot of amperage to start the puddle. Thicker Al, more amps. I wouldn’t go under 200 amps, preferring 250 amps as the lowest to consider.

Then practice, practice, practice. Tig isn’t a skill you pick up in a day or two. Thats why I say have this part done by a pro.
 
PK1 said:
Yep, Tig it is. Question I need to answer is do I go buy a tig welder so that I have one for future use, or do I pay someone to do it for me. Hard to justify two welders when my welding work is at best minimal.

Purely for educational purposes, why would you not braze this?
Click to expand...
Well, I have 4 welders, and my welding work is minimal. LOL!

I'd look into the Primeweld TIG225X. It's a 225 amp AC/DC TIG welder, also does stick of course. I've had mine for over 3 years and I love it. Plus thier customer service is second to none. The owners are very active on a Primeweld Users group on Facebook. The warranty is the best out there. 3 years, no questions asked, shipping included. I've seen users post in the FB group, get a response from Dustin or Gene (owners) on a weekend, and get a replacement machine shipped on Monday. For $869, it is just unbeatable, IMHO. Or wait a few more days for the 335 amp machine to come out - at more money - but what a machine that's going to be.

As for your last question, well, I can TIG weld for starters, and I've never had great luck brazing anything for that matter. LOL! Although, I have had great luck using TIG and aluminum bronze brazing wire on cast steel. :)
 
I concur with the others, take it to somebody who already has the skills. Then, buy a good AC TIG and go to work acquiring the skills for the next time. I've been TIG welding off and on for over 40 years. I still make a mess of aluminum jobs.
 
In general I use MIG much more than TIG. However, that also says I do steel much more than aluminum.

I have done MIG aluminum with a spool gun, but that was building up the edge of a 1/4" thick piece of a snowmobile frame that had ripped the mounting bolts thru the edge. I would not try MIG on aluminum much thinner that that. The warpage alone would be terrible.

I have had some success with aluminum brazing see:
https://www.hobby-machinist.com/thr...-window-regulator-mechanism.91146/post-831738
https://www.hobby-machinist.com/threads/2021-potd-thread-archive.103242/post-820961

Luckily I only had a single joint/interface to connect.
You are right to be concerned about reflowing your first joint while working on the second.....

Brian
 
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