Aluminum, MIG or Brazing?

[JRoque]

Hi. I'm new to welding with one weld under my belt. No, I didn't weld under my belt... nevermind, I'm new to this.

For my second ever welding project, I want to build an aluminum door/gate for the side of my house. It'll be a 3' x 6' (~1M x 2M) door built out of 1" (~25mm) square aluminum tubing, 1/8" (~3mm) wall and mounted on two hinges. The steel one there now has corroded off the hinges and needs replacing.

I have a small Lincoln 25 to 135A MIG welder that can also do aluminum with an optional kit and aluminum wire. I would have to buy this kit plus a bottle of Argon to do the job.

On the other side, I have read online that brazing with newer rod materials from the likes of DuraFix, HTS-2000 and others is a good substitute for MIG welding. For that I would have to buy a maap gas kit (propane is not hot enough?) and the brazing rods.

Considering my application, and assuming the initial investment in either method is about equal, which way should I go? Will brazing the gate be strong enough? Will it stand up to the elements? Being new to welding, how difficult will it be to learn each method?

Regards,
JR

 

[shenion]

My experience with Aluminiweld and one other rod I can't remember was that aluminum brazing is ok for big cast stuff and great for filling holes. Still it takes a lot of practice to learn and careful application for it to work right (like needing to stir the weld pool.) It is also very slow work.

Aluminum MIG welding is a bit finicky to set up and get the right voltage, wire speed, torch length and travel speed. But once figured out, it is very fast. Expect the wire speed and torch speed to be twice that you are used to. A longer torch/work gap (1/2-3/4") also.

I would get some 0.035 4043 wire or 0.035 5356. Forget 0.030 4043 without a spool gun. Use a 0.040 or 0.045 tip as the aluminum wire expands a lot more than steel.

Don't know what the aliminum kit comes with. All you should need is wire, tips and argon.

1/8" will be about the limit of what a 135A MIG can do..

 

[JRoque]

Thanks Scott, thorough as usual.

I'm ordering the aluminum kit that comes with a new liner, drive roller, 4043 wire and tips.

Should I order an Argon bottle online or is it better to buy it locally? I've heard that some refill places won't work with any bottles they didn't sell. I have an Airgas shop close by, I'll give them a call and ask. Also, what size? They come in 20, 40 and 80CU. No clue how much I'll really need but would rather buy the smallest one that will get me through this job.

Regards,
JR

 

[shenion]

Normal gas flow is 20 SCFH (Cubic feet per hour). So, a 20CF tank will provide 1 hour of weld time (there is some wasted.) A 20CF would probably do fine.

I have a 125CF tank, lasts me almost a year of use (usually a bit every weekend.)

Best is to get a tank from AirGas. You can go out and buy a nice shiny new tank. Then take it to be "filled" and you get back a beat up used tank. They sold me my 2 tanks for a bit less than the best deal I can get for a new one.

I started with an 80CF and they swapped it for a 125 for $14 + fill.

The kit looks good as it has 0.035 wire and tips. 0.030 is too much a pain to use without a spool gun.