MIG welding and advice
 

Today the robotics team walked into our machine shop to clean it, and found this:


It is a MIG welding torch.

Now, we do not know who left it there (we have our suspicions) but, if they are interested in letting us keep it, we would be VERY happy to use it. Myself and one other person on the team do have experience using a MIG welding torch, plus we could see if a sponsor would be willing to send us one of their professional welders for further instruction.

This would be the first time we had a welding torch, and the question arises if this room would be alright for welding.

We could get access to a table that we need for it, and we would probably either open a window, or, if needed, install a vent for the excess gases.

Next, in order to weld aluminum, the manual says we need 100% Argon gas. Where can we get this, and how expensive is it?

Thank you for the help. More pictures can be found on the blog here: http://robolions3397.blogspot.com/

Re: MIG welding and advice
 

I'd suggest getting some sort of booth setup with some kind of curtain as a door. The arc from an arc welder (such as MIG and TIG) is as bright as the sun, and can cause eye damage easily. If you cannot get a booth, make sure there is some sort of see-through welding curtain. That way you can safely see what is going on inside without being blinded. The arc can also cause sunburns to people nearby it. We have a heavy leather coat that our welders wear when they tig weld for that reason. (we don't MIG weld our aluminum)

(you can see the curtain we use in the pictures I attached, and you can sort of see the booths we have in the background. Sorry for the poor image quality, I had my friend record a video of me TIG welding with my phone, not the best image quality)

As for gas, yes. It does have to be 100% Argon. That can be bought at different welding supply stores. I'm not sure how gas refills go for us because we haven't needed to refill it during my time on our team, but the closest place I know is an Airgas store.

Praxair seems to be a really credible place to buy it too.

http://www.praxairdirect.com/Special...ons/Argon.html

I'm not sure on the price. I found on a website it is $.50 per 100 grams.

Hope this helps!

Re: MIG welding and advice
 

If welding steel is like stitches, welding aluminum is like brain surgery. It is challenging, and you absolutely must have competent instruction.

You cannot weld indoors without full and complete vetilation. "open a window" will not cut it. The room also needs to be essentially fireproof - sheetrock is not fireproof.

If you ever weld steel with that welder, it is useless for aluminum. If you dedicate it to 100% aluminum, and use the right supplies, then MIG welding (really, GMAW*) will work well for aluminum.

100% argon is not much different in cost from any welding gas. You will find that it is not a great expense, even if you rent the tank (common) and the regulator (usually you buy one), the cost of the gas is comparable to a nice dinner for four.

So, your next steps:
1. Can you really keep it?
2. Get someone who is an expert aluminum welder (not a steel guy who has done some aluminum. Trust me here) and have them help you...
3....find a good aluminum welding wire, and...
4. A source of gas, and....
5..Invest in a set of "aluminum only" tools (your welder will explain)
6. And personal protective equipment (mask, gloves, apron, etc)
7. Then find a location approved by the fire marshal (in most states you require a fire dept. permit to do indoor welding)
8. and practice, practice, practice. Then go and practice more. After 100+ feet of welding bead, you'll be passable.

This is NOT a lot of money, but step 2 for advice and instruction is critical...

Don

*Gas Metal Arc Welding
**Disclaimer: I know a lot about aluminum welding, maybe too much, but my eye-hand coordination stinks.

Re: MIG welding and advice
 

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.

Re: MIG welding and advice
 

1. I think we can keep it, mostly due to the fact that the only keys to the room that was in are in possession of our captains, our coach, and our teacher sponsor (who expressed interest in giving us a MIG welder).

2. We can do this. The guy who welded our aluminum robot last season ( http://www.chiefdelphi.com/forums/sh...light=Serenity) was a professor at the local Tech College, and is very good at his job. He can teach us.

3. What is an example of good aluminum welding wire?

4. We should be able to find some thanks to Justin

5. I will ask him tomorrow

6. We can get those

7. We might have an area in our school's wood shop (away from all of the wood) that would allow us to have ventilation and a curtain, and be fire-safe, we would check with this to be certain (to make sure it is no going to mix with the wood).

8. Sounds like a plan.

Thank you so much!

Re: MIG welding and advice
 

OzarkGas will be able to get you anything you need for welding; gas, wire, guns, etc.. And hope you have a great experience with your welder!!

Re: MIG welding and advice
 

I have done Aluminum TIG welding, I taught myself, (I think I did one steel TIG weld), I can TIG weld aluminum better than steel, which isn't saying too much.
1. clean the surfaces very good
2. use stainless steel wire brush( and only use it for this purpose)
3. electrode distance from material should be 1/2 the electrode thickness
4. when the weld puddle turns reflective, start inserting filler rod (you can melt through very quickly wspesially with thinner metals, so this takes skill)
5. practice, practice practice :D

not 100% shure on #3, been a while.

Re: MIG welding and advice
 

Always consult the manuals, and defer to experts. I am neither, just someone with a fair bit of FRC experience and a bit of welding practice under his belt.

First off, congratulations! Welding is a great resource to have, and although MIG welding is more difficult with aluminuim, don't let that stop you. Compared to TIG welding, MIG is faster to setup, so you can run more beads, but is more difficult to get right. Finding the right wire feeds and power levels are very important to getting good results. Think of it this way: although our main student welder and I love TIG welding aluminuim, he welded two full 1/16" alu frames last year with good results. MIG is still a great way to go.

I wouldn't recommend welding in there, at least not just with a window open. Others have more experience with this, but we weld in a dedicated booth with one of those welding safety curtains. The walls are plaster, I believe, but the floor is some type of concrete or sheetrock. We weld on an (unfortunately not flat) metal table. Keep in mind, technically, exposing even concrete to high temperatures can have disastrous consequences. (Such as when doing aluminuim casting, the molten aluminuim can vaporize moisture in the concrete with, shall we say, dangerous results. Welding shouldn't get the concrete close to those temperatures, though, even if you weld right on it.) So, be safe. We also use a fume hood. In your case, I'd consider welding outside. If you use appropriate safety equipment, don't weld tired, and have proper training, welding isn't dangerous, and it's quite fun. Don't be scared away. That said, consult experts and manuals first.

One last thing, this probably isn't the first time you've heard this, but welding is hard. Like really hard. Welding practice is not only a lot more fun than CAD practice, but essential to getting good results. You're going to need at least several days in the welding booth before getting even passable results. Also, warping is a real issue. Weld on a surface you KNOW to be flat, and check everything's squareness after tacking and every weld, squaring everything again if appropriate. Weld carefully, and be smart. Oh yeah, and in case I haven't said this enough already, listen to those with the most experience (the experts).

Good luck, have fun and be safe!

Re: MIG welding and advice
 

Sorry to derail the thread a bit, but why would welding steel make a welder no longer fit to weld aluminum? The obvious answer is that it messes it up in some way (just as crimpers that have been used as pliers will never crimp again), but how?

Re: MIG welding and advice
 

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.

Re: MIG welding and advice
 

In a former life time, I TIG welded steel & aluminum with the same equipment. Aluminum generally needs a bigger welder, a HF starter & is pickier with the shield gas.

MIG is slightly different. Since aluminum is softer, you generally need a spool gun rather than having the wire feed in the welder so the wire does not kink.

As previously stated. Have an expert help set up the machine, advise you what you need. & teach you how to weld. The thinner the pieces you are welding the more difficult it becomes.

Re: MIG welding and advice
 

Well, maybe it was a slight overstatement. In reality, if you buy a new gun and hose (and drive wheel for some welders), you can swap them for steel and aluminum.

The issue is one of contamination: A tiny bit of steel dust (even at the molecular level) will cause your aluminum welds to fail or be very weak. For this reason, you must take extreme care that no steel of any kind - dust, grinding debris, or even the residue from a welding gun used for steel - gets on or near the aluminum. That's also why you need a stainless steel brush and must dedicate all your aluminum welding tools to aluminum only.

In the automotive world, where aluminum repairs are common, it is almost universally mandatory that a body shop have a dedicated aluminum roof in their shop. Just being in a corner "away from the steel" is very insufficient. At the very least, a curtained-off area that you wash down with water before using anything is required (for car repairs, which are safety-sensitive).

Again: A good aluminum welder will tell you all this, along with helping you find good wire and other supplies.

Welding IS fun, but it really is hard, too. Worth It.

Re: MIG welding and advice
 

New just arrived:
1. The MIG welder is ours

2. We happen to have an old welding booth at the school! We will just need to replace the old Steel table with a new aluminum one, get the gas (which our teacher sponsor is going to try to get the school to provide) and some equipment, and we are good to go.

3. Our local welder is happy to come in and teach a few of us to weld aluminum.

4. The nearest OzarkGas supplier is 30 minutes away, we are gonna see if we can find someone closer, preferably local.

Thanks for all the help, it looks like 3397 will have ourselves some welding next year.

Re: MIG welding and advice
 

All I can say is good luck.
My expectation you will be very disappointed after spending the $ to swap it over to aluminum welding just to find out that the machine/welds are not able to reliably meet your needs. If you want a consistently good weld with a low machine cost tig welding has the advantage over mig welding. (The cost of Mig welding with this welder is not worth the investment. You need a spool gun that pulls the wire out not pushes the wire out. If you use this welder with soft AL wire, it will make a birds nest in the unit. The best way to mig weld with Al you will need a new lead with a pull drive in the head of the gun. It is NOT worth upgrading this welder! Yes they have the adapter to be able to weld AL with this welder but please do your research before you put any thing into this welder.) If you are welding anything 1/8" or under you will be more pleased with a tig welder because you will be able to control your temp, looks better and it will produce the clean and strong weld without porosity! For example look at this welder,
http://www.millerwelds.com/products/...p?model=M00337
Best of luck.

Re: MIG welding and advice
 

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.

Re: MIG welding and advice
 

If that MIG unit is less than 200A (it says 125 on the front) you'll likely run into some issues with aluminum.
As mentioned you want 100% argon as well.

My Hobart 210MVP has a spool gun but there's limits of what you pull off with low power delivery.

Re: MIG welding and advice
 

You will probably only be able to weld up to 1/8 maybe 3/16 inch aluminum plate with that machine. We have a 180 amp Miller TIG welder on campus which can weld a little under 1/4 inch Al. When we have our robots welded, some of our thicker components (1/4 - 1/2 inch) have to be taken to our welders off campus shop with a more powerful machine.

Re: MIG welding and advice
 

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.

Re: MIG welding and advice
 

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.

Re: MIG welding and advice
 

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

Re: MIG welding and advice
 

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

Re: MIG welding and advice
 

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

Re: MIG welding and advice
 

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

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

Re: MIG welding and advice
 

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.

Re: MIG welding and advice
 

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.

Re: MIG welding and advice
 

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

Re: MIG welding and advice
 

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 :cool:) 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.

Re: MIG welding and advice
 

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.

Re: MIG welding and advice
 

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.

Re: MIG welding and advice
 

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.

Re: MIG welding and advice
 

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... :ahh:

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.

Re: MIG welding and advice
 

Get the PN, call Lincoln, make sure you can use it to weld aluminum before you go through any more hassle. They will also be able to give you PNs for the appropriate equipment you'll need (spool gun, gas controller, wire, etc) Also consider keeping your welding table surface steel, it will be easier to maintain in general.

I think that if you keep your expectations realistic, you'll do fine welding aluminum. However, those realistic expectations may be no welding anything thicker than 0.093in in aluminum.

Having said that... MIG welding aluminum can be tricky. It isn't rocket surgery, but requires careful setup and very clean equipment and material. The setup chart inside the cover is a good start.

http://www.weldingtipsandtricks.com/
^IMO this is the best online resource for welding. Not exactly text book, but Jody REALLY knows his stuff and how to get it done. Pay careful attention to his MIG welding Tip series.

I think you mean to say "spool gun" as there is no such thing as a TIG "gun" only TIG torches, at least in general. It may be semantic, but these things matter.

100% Ar is suggested by many, but is not always the best shielding gas. A helium/argon mix is best for welding aluminum (TIG or MIG imo) because helium has much better heat transfer properties. This lets gas-cooled torches run cooler, and transfers more heat to the work. Both of these increase the capabilities of the welder. I like 50/50 mixtures, but even 25% helium makes a big difference. Helium also helps create a more stable MIG arc.

^ Agree 100%. Thin-walled steel (think 0.035in) can have a comparable weight to aluminum tubing of similar strength. Welding it is a helluva lot easier. Just keep some sharp drill bits (step drills are great for this) around, learn how to use riv-nuts, and don't cheap out on the hacksaw blades (Lennox bi-metal blades are the best IMO).

My qualifications on this topic:

-Formerly ASME & AWS certified TIG welder for alloy steel and aluminum
-2 years of experience developing MIG welding wave-forms (specifically for titanium), researching welding theory as well as experimentation. A lot of this effort's success was a result of understanding and implementing argon-helium mixtures.
-Taught welding for a year in college, also started and ran my colleges welding lab (BTW: I started every student off welding aluminum with 50ar/50he gas, no big deal)

Re: MIG welding and advice
 

Absolutely correct.

However I rarely do that because I have a handy propane torch to preheat if need be and my welder is getting up there in power capability.

So I was curious (it's been a while) I called AWISCO where I buy my gas and they are getting back to me about the cost difference between the custom mix of 25% Helium / 75% Argon (I bought my previous tank elsewhere and apparently this was something unusual for them) and 100% Argon.

Last I looked the cost of the mixed gasses can reach a point where the cost of savings of the machine (though a donate machine can skew this) can make more sense to buy a more powerful welder (because it's cheaper over usage). Course if your usage is really low maybe it doesn't matter.

You can get a welding gas mixer but they are not typically cheap.

Re: MIG welding and advice
 

It's true that helium is pricey, and helium prices have spiked recently. My last price out was (in round numbers) $100 for Ar and around $250 for 50/50 (special order). This was for a 300ft^3 bottle refill. FWIW I have used 50/50 and 100ar with a Lincoln Precision TIG 375, their top-end TIG machine at the time, and much preferred 50/50 for aluminum as compared to 100ar.

At work we use a gas mixer, that was a little over a grand. I'm sure one could make their own crude gas mixer for not huge amount of money though, i.e. just 50/50, not 10/90-90/10 like a high-end mixer.

Looking around on the internet, some people think 50/50 is too much helium and suggest between 25/75 down to 5/95. Last time I checked 50/50, 25/75, and 10/90 are available OTS.