MIG welding and advice

[MrBasse]

Originally Posted by Justin Shelley

In order to weld Aluminum with a MIG you have to have a TIG gun. As far as getting gas I would contact a welding gas supplier near you and lease the tanks, OzarkGas is who I would contact first. They are extremely reasonable and highly qualified.

Originally Posted by Justin Shelley

It's because you have to have a completely different setup to weld aluminum then you do steel. I wouldn't say it makes it completely useless but it's expensive to keep both setups and time consuming to switch back and forth.

Be sure that you understand welding processes before you give out too much information. MIG and TIG are abbreviations for the same process (GMAW), but differ greatly in the fact that the machine, electrode, filler material delivery, cost, much more are dissimilar.

You can MIG weld aluminum, but as mentioned the contamination is hard to avoid if used for other materials. Also the quality of weld achieved from a MIG welder is generally not to the same level as one can get with a pedal operated TIG set-up. It should still be plenty fine for FRC uses, but don't expect beautiful flowing material spec rated aluminum welds out of the machine that the OP has.

For gas, check some medical supply shops and a quick google search for your area based on city alone brought up a handful of welding supply shops. Looks like you guys are in the Airgas supply area, as well as many others. Between Airgas, Delta, and Rod's you have your choice of 3-4 shops within ten minutes of the city listed in your location.

The best advice is to get some training from someone who knows what they are doing and then run through a whole spool of wire practicing. But, practice on the same material you will be using during the season. If you are buying a particular type of aluminum tubing, get a chunk of it. Buy a lot of usable drops from your supplier and start burning holes in those until you can get a reliable bead built up. Then start connecting pieces together and see what it takes to break them apart. Some of the most fun we had in welding classes was the "toss test." Just find some concrete and chuck a test weld in the air ten or fifteen feet. If it survives the landing then move on to the real part to be welded.

And have fun, welding is one of those addicting hobbies you never seem to stop doing once you start.

[FrankJ]

Originally Posted by MrBasse

... before you give out too much information. MIG and TIG are abbreviations for the same process (GMAW),

In practice MIG & TIG are very different. In MIG your electrode becomes the filler & is consumed. In TIG your tungsten electrode is not consumed & should never touch the weld puddle. While you can buy machines that do both the setups are very different.

[MrBasse]

Originally Posted by FrankJ

In practice MIG & TIG are very different. In MIG your electrode becomes the filler & is consumed. In TIG your tungsten electrode is not consumed & should never touch the weld puddle. While you can buy machines that do both the setups are very different.

Exactly right, but both MIG and TIG fall in the category of Gas Metal Arc Welding (GMAW) by using a shielding gas (Argon, Carbon Dioxide, etc.) rather than Shielded Metal Arc Welding (SMAW) using a flux coated filler material. What you said is exactly what I wanted the poster to look up and learn on his own.

[FrankJ]

Not to be confused with a flux core wire welder which looks a lot like a MIG.

[MrBasse]

This welding stuff sure does get confusing... We should all just switch to glue

[FrankJ]

Thermo Setting? Synthetic monomer? Synthetic polymer? horse glue? Or my personal favorite Gorilla glue?

[DonRotolo]

Originally Posted by FrankJ

Thermo Setting? Synthetic monomer? Synthetic polymer? horse glue? Or my personal favorite Gorilla glue?

Friction stir welding. That's what I want to try. I have my cordless drill....

Gorilla glue? Why in the world would you want to glue gorillas together?? (I can see why you'd want to glue horses together though - increased horsepower, of course).

[FrankJ]

Picture a gorilla on top of a pyramid swatting Frisbees out of the sky while holding one of the Refs. Then you will understand the need for the glue.

[DampRobot]

Originally Posted by DonRotolo

Friction stir welding. That's what I want to try. I have my cordless drill....

Handheld friction stir welder... Yeahbuddy!

SpaceX does friction stir welding to make their rocket bodies, it's really a extremely cool process. Worth a google for all those looking at this thread.

On a side note, I've heard the reason that we beat the Russians to the moon was because we had better welders. Ours could figure out how to weld tanks which were good enough to hold liquid hydrogen, whereas the Russians could only make kerosene tanks. We ended up with the slightly smaller and more reliable Saturn V for our moonshot, and they ended up with that massive kerosene powered rocket that looked like a Christmas tree--which turned out to be impossible to control in the sky.

[DonRotolo]

Originally Posted by DampRobot

We ended up with the slightly smaller and more reliable Saturn V for our moonshot...

I have never before seen the words "smaller" and "Saturn V" used in the same sentence. Wow.

[Ian Curtis]

Originally Posted by DampRobot

Handheld friction stir welder... Yeahbuddy!

SpaceX does friction stir welding to make their rocket bodies, it's really a extremely cool process. Worth a google for all those looking at this thread.

On a side note, I've heard the reason that we beat the Russians to the moon was because we had better welders. Ours could figure out how to weld tanks which were good enough to hold liquid hydrogen, whereas the Russians could only make kerosene tanks. We ended up with the slightly smaller and more reliable Saturn V for our moonshot, and they ended up with that massive kerosene powered rocket that looked like a Christmas tree--which turned out to be impossible to control in the sky.

For what it's worth, this is one of those great sounding stories that is almost certainly false. The Soviets never invested in hydrogen rocket engines, despite repeated funding requests from Korolev, who was basically their Von Braun. As such the Soviets were way behind, particularly because the military had been building the engines for the Saturn V long before NASA even planned to go to the moon. The military recognized that the engines are typically the schedule driver on aerospace projects, and figured they could develop vehicles to go with them later. Or another way, they just wanted bigger more expensive toys than the other branch, since the Air Force and the Army both wanted in on the missile game.

The N1 was actually lighter (still weighing several million pounds) and shorter (still nearly 350 feet tall), than the Saturn V, but it had a ridiculous number of rocket engines (43!!) compared to the Saturn V's 11. It also had an additional stage to make up for the performance loss of Kerosene vs. H2.

Taming Liquid Hydrogen is a wonderful book (if you're a huge nerd like me ) that NASA put together that describes the technical and political challenges of designing the Centaur upper stage that is still in use today.

I love Kerosene Christmas Tree... great name!

EDIT: Moral of the story I forgot: Rocket development (and aerospace product development in general) is so complex it rarely gets held up for just one thing.

[EricH]

Originally Posted by DonRotolo

Friction stir welding. That's what I want to try. I have my cordless drill....

Originally Posted by DampRobot

Handheld friction stir welder... Yeahbuddy!

SpaceX does friction stir welding to make their rocket bodies, it's really a extremely cool process.

Handheld stir welder? Try a mill instead, it'll work slightly better. (Trust me on this. I spent a good portion of my work day today on one of the SpaceX stir welders--and that's actually pretty typical for me.)

BTW, friction stir welding is one of the FEW new technologies with almost no practical application to FRC robots. Maybe the sheet metal bots could use it, but even they'd have a hard time. Not saying it isn't cool to watch, though.

[bake]

Wow, A lot of confusion about welding here. MIG (GMAW) and TIG (GTAW) are not related at all except that they use an electric Arc. For your application with your welder a spool gun would probably be the best bet for Aluminum MIG. It is difficult(but not impossible) to push the soft aluminum wire through the liner. Argon is the correct shielding gas. The filler wire will have to match the material being welded. Cleaning is the key to Aluminum. The oxidation that forms on Aluminum has a higher melting point than the Material itself. Wipe parts clean with Acetone. SS wire brush to remove oxidation. MIG Aluminum is difficult but can be done. If you have any specific welding questions I can probably steer you in the right direction.

[MrForbes]

Just to throw a monkey wrench into the whole discussion....in 2011, we built a steel robot chassis. A freshmen borrowed a MIG welder, and did all the welding. If you use thinwall steel tubing, the weight isn't really very much more than using thicker wall aluminum. And MIG welding steel is easy. Even I can do it.

[MrBasse]

Originally Posted by bake

Wow, A lot of confusion about welding here. MIG (GMAW) and TIG (GTAW) are not related at all except that they use an electric Arc.

Not a lot of confusion, just different discussion from different sources. Both use an arc, both use a stable shielding gas (many times the same type of gas too), neither make use of flux due to said shielding gas, and both commonly (MIG always) use a filler material added to the arc to create strength in the weld. The book I used for my welding classes lists TIG as a GMAW process that is also known as GTAW. The more acronyms you throw in the mix the more confusing things get. Tungsten is a metal and that is where the M comes from in GMAW, so I don't feel bad about saying what I said. If the world has changed since then and dropped my views, I'm happy to change my ways.

While this thread has remained educational, it has completely derailed off topic, which is so strange for CD...

That being said, if I was the OP I would make use of that welder and build a steel chassis. Every time we build an aluminum chassis, we swiss cheese the thing for days to make weight. Every time we build with steel we come in comfortably under weight.