so im about to by a mig welder (135 amp lincoln) and it says it can weld aluminum.... i've always heard welding aluminum is very hard.. other than the special wire what would i need? and i am in no way a professional welder, but i have done plenty of small welding jobs and what not, and can make good beads on mild steel, but could a beginner like me make any decent welds on aluminum.... cause im thinking of modifying some endtanks on an intercooler

 

argon, teflon liner, larger tips. for welding anything like an innercooler i'd use GTAW (tig) actuaslly i just welded one last week and did use tig on it.

 

Never tried welding with my MIG welder, always used a spool gun. Regardless, with the wire welders the wire speed will have to be waay up there and you have to move the gun pretty quickly also.

If you welding near or on something nice, invest in a can of anti-spatter spray. It's really easy to weld aluminum with a mig, infact that's how all the featherlite trailers are put together. Just a heck of alot faster puddling than your used to with steel.

 

Not trying to hijack the post, but I'm three steps ahead of stevedave454 with trying to weld aluminum so I thought I'd see if my experience can help him, as well as myself.

I recently ponied up for a Lincoln 135 Plus MIG setup. I did some practice with mild steel and got good welds right out of the gate using the correct wire and 75/25 AR/CO2 mix.

One of the main reasons I bought the MIG was to be able to weld aluminum and stainless steel. I purchased the aluminum feeder kit, and rented a bottle of 100% Ar gas to try some aluminum welding before I do anything that is important. I tried to weld some 1/8" thick material that I had in the shop. I cleaned both surfaces with a stainless brush, and even pre-heated the parts with a propane torch (welding supply store recommended this to make welding easier and prevent cracks).

I was psyched up and ready and very disappointed when it didn't work well at all. It seems like I'm not getting any penetration into the parent metal. The aluminum wire melts and seems to only fuse to itself. Plus the weld looks boogered and is extremely weak (obviously since the parts aren't actually being fused). I don't get it. I've got all the right stuff! I tried cranking the amprage all the way up, and lowering the wire speed to try and build heat in the base metal, but the results were the same. I even tried reversing the polarity to see if it made a difference, but no dice. Any ideas/help?

 

http://www.lincolnelectric.com/knowl...compactmig.asp

 

Thanks for the info. Apparently regular polarity is the correct method. I'm going to try and weld some thinner material and see if it works better. Then step up. According to the info on the website I'm right on the edge of what a 115volt welder can accomplish. I don't plan to weld enough thick aluminum to make a switch to a 230 volt machine worthwhile, especially since I already have an arc machine that can weld up to 1/2" steel plate, and if I am welding material that thick it is going to be steel.

I will try again and post back with the results.

 

Hey! Just ordered a spool gun and a controler to convert a Hobart (Miller) 175 MIG for alum. useage. I'm pretty excited ;-) I tried welding without a teflon liner, just elevated the welder about three feet and kept the gun's line straight to help it feed somewhat. I got a few good beads on some thicker pieces the wire kept jamming up "birds nesting" The spool gun should be the cats' meow for what I wanna do bumper supports, radiator mounts, brush guards and what-not.

What grades of aluminum are best for welding? I've heard only certain stuff is good for strength and ability to hold together.

 

You nailed it. The aluminum wire is to soft to be pushed all that way through the liner (even with teflon) This is why they have spool guns. Off the spool and out. We have a new really trick aluminum welder at work that isn't a spool style. Its so new (3 days) I can't even pronounce the name yet! It is trick though. It is infinately adjustable and works really well. It should for $8500.00!! I also prefer tig welding for aluminum work. The heating the material trick is "usually" only used if you are welding really large, thick material.

 

clean it w/ new a stainless steel wire brush that you haven't used on anything else. You can purchase a new tig welder on e-bay from 200 to 400 bucks and it's worth it

 

You need to use a tig welder on something as thin and percise as endtanks. To mig weld with aluminum you need lots of amps 200 min. a push pull gun, spoolgun or a short gun kept straight. Use one size larger tip than the wire and use 100% argon.

 

To tig weld aluminum you use AC negative electrode with a pure tungsten,green band, in the torch.

 

well a ceriated tungsten will last longer since it takes more heat, but that isnt the subject here, I havent seen any great sucess with getting pretty welds with a mig on aluminum, functional yes, for the intercooler i would also rec. tig but alot of manufactures use mig and alot of those are automated so that might explain it, removing most of the human factor. as with any aluminum welding proper filler and clenliness is important though the manuals say to scrub it with a new stainless steel brush, alot (the aluminum oxidation in much harder than the base metal and if not removed will not allow proper penatration) and then cleaning with MEK yes the same stuff used as hardener in bondo to clean it then weld it, then if you stop you must clean the oxidation again before continuing also the aluminum will get shiney just before it melts so if you can see the arc area get shiney as you are starting with the mig that should be about the right time to start moving, also 1/8 stock being butt welded should be beveled some to get better penatration

 

You absolutely want to do that job with a tig. Aluminum welding uses way more amperage then steel welding and puddle control is much more difficult. We have aluminum migs and tigs here as well as we design and build aluminum robotic welding cells (ie Ford GT frames) and for something as thin, and precise as what you want to do, you need the puddle control that comes with a tig welder. I'm not saying don't learn how to mig weld aluminum......I'm just saying don't do it on this particular part. I'm pretty sure the welder your looking at will not have enough nuts to weld aluminum properly. Getting proper penetration when welding aluminum is difficult and usually requires a min. of 200 amps.

 

Ditto on that...use a tig welder and you are going to need alot and I mean alot of practice before you should even attempt to weld something like an aluminum tank, aluminum is the hardest metal to weld, if your heat is to low you wont get penetration and just alittle more heat and you just melted through the aluminum...takes years to learn how to do it right!!!

 

Yeah some good info has been posted, but i doubt stevedave wants to spend 2k plus on a ACDC tig with close to 200amps, let alone learn how to weld with a tig. Either call a welding shop and get it done there, or try using 5356 alum. with your Lincoln 135 which has a stronger tensile strength, compared to a 4043 alum which tends to bend easier in the drive rolls. I would not try to use any heavier wire then .030 alum with that 135amp mig. Im not sure what size wire you tried to weld with, but chances are your alum wire was at least .035 or .045, which is alot more common with small 1lb spools because they are meant for spool guns which normally have power sources capable of larger wire.

 

Wire speed is how you control your aperage with most welders, I would say you were cranking the voltage and turning down your current by turning down the wire speed.

 

I weld aluminum with a Miller on AC high-frequency pulse TIG.
Ive used a few Lincolns capable of aluminum, and they were decent.

Problem with the MIG is the wire likes to blow right through
the metal.. Yea, you might run a solid consistent bead for the
first 30 seconds.. then, the aluminum heats up.. it's inevitable
you'll blow through.

Too cold and you might as well use duct tape to fuse the two!

Pulse is the way to go, does it have that option?

 

Just a tip, when I was welding alum with a MIG I found that using a push method was much more effective then a pull method. I use pull most of the time for steel, but I found it easier to get good penetration in alum with the push method.

 

Screw MIG welding aluminum. Unless you have a proper setup, it's worthless as far as strength goes.

 

One more thing not mentioned.

Yes, you must use a stainless wire brush but even that isn't good enough. To get a good weld, the metal must be very clean. Even new untouched aluminum is dirty. The best way to clean it is with a rag and some acetone.

I've never tried aluminum welding with my 110v MIG at home. All the aluminum welding I've done was on a 220 machine at work with a spool gun. As much as I'd like to try it, I've never had a chance to do any TIG.

If I need anything special done such as weld a bung in one of my fabricated valve covers etc, I'll spend the money and give it to someone with a lot of experience to do it.

 

Spool gun MIG is the ideal setup. other wise, have fun bird nesting that wire even IF you are using Teflon liner.

 

I couldn't agree more about the liner. I wouldn't say a spool gun is ideal though, least not for me. I've had an aluminum gun for two years now and had good success w/ making parts.

I wish I would've skipped the spool gun and saved towards a TIG- in the first place.

The spool gun works great for larger items like bumper supports, radiator mounts, I even repaired a "fin" on the bottom of an outboard motor for a guy. They are great for production purposes or larger parts fabrication. Forget about welding thin sheet metal -anything- with a spool gun though. The welds aren't as pretty and a majority of the things I'd like to make out of aluminum would require to hold fluids/pressure like rear diff. cover, coolant tank, etc.. The tig would be a better investment.

 

Yup. And as far as TIG machines go, my "professional" opinion of using one 5 hours a day says go with an inverter. Initial cost is higher, but has less current draw and more stability, along with more features.