Welding Tips and Tricks

Hey guys.

Just reaching out for your advice. I have had a few 3/8" 6061 aluminum plate welding jobs come through the shop this month and it tested my welding machine capabilities. I am using a Lincoln Square Wave 175. I had to weld up some 3/8" plate to 3/8" plate. As you know, the aluminum acts as a BIG heat sink. I tried just diving in and start welding and it didn't go well at all. I had the 175 cranked up all the way using 100% Argon, I am using a water cooled torch, so that really helped out a bunch! But, I just couldn't get the metal hot enough. The weld I attempted looked like crap.

I then switched to a mixture of 70% Argon / 30% Helium (this is what they had available at the store) and I also placed the aluminum plate inside my BBQ and warmed it up to 350 degrees about. (BTW, I was using an 1/8" 2% Thorniated Tungsten pointed tip on AC with a slightly flattened end using a dedicated tungsten grinder). This seemed to help, but I still couldn't weld the 3/8" aluminum like I have welded 1/8" or 1/4" aluminum with the same machine. It seems this 3/8" plate just was too thick for the 175 even after using a mixed gas and pre-heating the metal. The weld puddle seem to get much bigger than I wanted and there was a black "smut" ring around the weld. I seemed to have a lot of impurities in the weld too. I had cleaned the aluminum with a dedicated S.S. brush and then used Acetone to wipe it down. I even tried sandblasting a sample piece, but really no changes.

The mixed gas and pre-heating helped, but I didn't "conquer" the aluminum. It didn't weld up real nice as I can when welding 1/4" or less.

So, what was I doing wrong or, do I need a BIGGER machine? I contacted Miller and they told me the Dynasty 350 would do the job. Lincoln told me the Square Wave 275 would do the job. Not sure I want to spend that kinda of money on a welding machine.

Any advice would be appreciated and thanks in advance for the help!

Mike

Depending on how big the 3/8 plate is in size your defiantly lacking in amps . If your welding close to the edge of the plate you may just about get it done , but if it's a large piece of material and your near the centre is going to take all the heat out of it..

This is a job i welded a couple of weeks ago , 6082 T6 ....5/8 plate with some 1/2 plate and 4x4 x1/4 wall box....Done with a Murex 350is set at 210 amps using 50/50 Argon/Helium with a 2% Lanthanated tungsten and pre-heat..

The biggest issue i had with this was the 1/2 plate , which is the radius ended part , had been cut out on a water jet and left the cutting media imbedded in it...After lots of cleaning with an orbital sander and SS wire wool and brush it cleaned up reasonably well , but still not as clean as i would have liked..

If i'm welding large thick section aluminium i sit it on aluminium box section spacers to keep it off the large steel bench that you can see in the photo's , that thing just sucks all the heat out of the material..

Hi Jared.

Thanks for your response. I did elevate the aluminum off of the welding table with small spacers so that the welding table wouldn't suck the heat out of the aluminum plate. I was welding in the center of the plate, so it was taking a HUGE amount of heat/power to get things welding. I think my SW 175 just doesn't have enough power to weld 3/8" aluminum plate. My welds turned out to be about an 1/2" wide after trying to heat the aluminum with the TIG torch. And the black crap floating in the weld puddle was nasty. And my arc was wondering all over the place too. When I watch Jody weld, his arc is just so stable!

I am thinking my machine just doesn't have enough horse power to make it happen. I don't know what else to do, since I used a mixed gas, lots of preheat (soaked the aluminum for 35 minutes in the BBQ at 350. The only thing I didn't do was use DCEN instead of AC, maybe that would have helped too, I don't know.

The Miller Dynasty is running almost $9000.00 when set up to weld, CRAZY! I just hate NOT having the right equipment to do the job!

Thanks for your reply.

Mike

BTW, your welding looks really good on that aluminum!!! Nice work!


Mike

Welcome, Mike,

The smallest machine I'm comfortable TIGging 3/8" aluminum is the Miller SW250DX (which can do 310A at 10%), but for a serious weld, some preheat is required to overcome the duty-cycle, and while I really love to mix some helium, it's not required.

The Lincoln PrecisionTig 375 is also a good choice in the lower end of machines that will comfortably weld 3/8" aluminum.

Note these are both transformer machines, at far lower cost than that Dynasty, and I've had 6061 pipe welds x-rayed with welds from both machines.

Steve S

DC with 100% helium. Is got to be super clean though

steve
what do you think is the smallest inverter could weld
3/8" with?
craig

motox wrote:steve
what do you think is the smallest inverter could weld
3/8" with?
craig

Dude, it all depends how patient you are.

motox wrote:steve
what do you think is the smallest inverter could weld
3/8" with?
craig

I would think, with a thorough pre-heat, you'd want a machine with a 40% duty-point of 210 amps. You can stretch this with helium and/or practice.

It can be done on less, but it's hard on the machine, the operator, and the electric bill...

Steve S

I'd venture to say that it would also depend how deep the fusion is needed.

FuSNSp68l0U

Just wanted to thank all you guys for responding to my help request. The Everlast 325EXT might be a machine for me to look at for the welding of thicker metals especially aluminum. The Miller Dynasty 350 is very expensive and the Lincoln Precision Tig 375 is a little less, but still above the Everlast by a bunch.

I just need to do more research and take my time to make the right decision.

I have realized how much I struggled with my Lincoln Square Wave 175 trying to weld the 3/8" plate aluminum. I was eventaully able to weld the pieces together but the weld was not great and turned out much wider than I wanted.

I want a machine that I can walk up and lay down a bead on 1/2" aluminum w/o any issues, maybe no preheat, and no mixed gas. Just fire up the machine and go! If I need to preheat, then I need to preheat.

Thank again guys for your help,

Mike

My Dynasty can do that, with out preheat its the 200 dx model just set it roughly at 70/30 and burn it i did 3/8 plate just the other day at 150 and welded across it so fast i almost had to keep the rod in it continuously but i had my machine at max penetration at 150 hertz

Your Dynasty must be better than mine! I have the same machine, and I sure can't get a good weld on 3/8" aluminum. That would require a groove weld with multiple passes. Not a good idea on aluminum. You might stick 3/8" together-but you can't get the penetration with the amps you have! And you sure can't get penetration at 150 amps!

3/8" aluminum with only 150A AC? I find that very hard to believe from what I've read, even if is a dynasty 200dx. I'm sure I'm not the only skeptic.....

Oscar wrote:3/8" aluminum with only 150A AC? I find that very hard to believe from what I've read, even if is a dynasty 200dx. I'm sure I'm not the only skeptic.....

With helium mix it's very doable or with preheat and straight argon. Most of all, it's operator skill. I've watched Shovelon do it. But he had many thousands of hours of experience behind a tig torch.

soutthpaw wrote:

Oscar wrote:3/8" aluminum with only 150A AC? I find that very hard to believe from what I've read, even if is a dynasty 200dx. I'm sure I'm not the only skeptic.....

With helium mix it's very doable or with preheat and straight argon. Most of all, it's operator skill. I've watched Shovelon do it. But he had many thousands of hours of experience behind a tig torch.

While that may be true, msumner made no mention of helium, which is why I'm partly skeptical of those numbers.

No one mentioned getting a 330ABP? Miller or Airco branded? 450amp single phase. Great machine frequency up to 100htz. Can be had in the sub $500 range.

Or even joint configuration.

I would get the Everlast Powetig 325EXT. Its in the 2,000 dollar range, 245amps at 60% duty cycle. 320 amps at 35%. I have the Everlast 250EX and its duty cyle is 250amps @ 60%. My machine has a very nice smooth arc. I have been welding 1/4 wall steel square tubing at 230 amps and can continually weld without stopping except for re-positioning and clamping. It came with a water cooled torch. The water cooler was around $300.00 and plugs straight into the back of the Tig machine. It powers on as soon as I turn on the Tig welder. I really like it. You can see Jody's review in the videos. If they would of had the 325EXT when I bought my 250EX I would of purchased it instead. You can always use more power. You can run the 325EXT on single phase power. Good luck!

Oscar wrote:

soutthpaw wrote:

Oscar wrote:3/8" aluminum with only 150A AC? I find that very hard to believe from what I've read, even if is a dynasty 200dx. I'm sure I'm not the only skeptic.....

With helium mix it's very doable or with preheat and straight argon. Most of all, it's operator skill. I've watched Shovelon do it. But he had many thousands of hours of experience behind a tig torch.

While that may be true, msumner made no mention of helium, which is why I'm partly skeptical of those numbers.

He also specifically said that he used no preheat! I would have to see this. I'm from Missouri, show me! When I weld .194 aluminum at work, I usually run about 190 amps, maybe 180 if I am using the 75/25 argon/helium. 150 amps for .375 material is just unreal to me.

soutthpaw wrote:No one mentioned getting a 330ABP? Miller or Airco branded? 450amp single phase. Great machine frequency up to 100htz. Can be had in the sub $500 range.

I agree - go big and weld happy

My machine is 60hz only, non-adjustable. I have not seen one that had adjustable frequency yet.

I see them regularly under $800, and sometimes under $400 (mine was $225).

MinnesotaDave wrote:

soutthpaw wrote:No one mentioned getting a 330ABP? Miller or Airco branded? 450amp single phase. Great machine frequency up to 100htz. Can be had in the sub $500 range.

I agree - go big and weld happy

My machine is 60hz only, non-adjustable. I have not seen one that had adjustable frequency yet.

I see them regularly under $800, and sometimes under $400 (mine was $225).

That little dial on the far right under the panel cover. Where the hf points are

soutthpaw wrote:

MinnesotaDave wrote:

soutthpaw wrote:No one mentioned getting a 330ABP? Miller or Airco branded? 450amp single phase. Great machine frequency up to 100htz. Can be had in the sub $500 range.

I agree - go big and weld happy

My machine is 60hz only, non-adjustable. I have not seen one that had adjustable frequency yet.

I see them regularly under $800, and sometimes under $400 (mine was $225).

That little dial on the far right under the panel cover. Where the hf points are

That is the high freq intensity knob, which only affects the intensity of the high freq spark.

It does not change the welding frequency - it is 60hz only.

MinnesotaDave wrote:

soutthpaw wrote:

MinnesotaDave wrote: I agree - go big and weld happy

My machine is 60hz only, non-adjustable. I have not seen one that had adjustable frequency yet.

I see them regularly under $800, and sometimes under $400 (mine was $225).

That little dial on the far right under the panel cover. Where the hf points are

That is the high freq intensity knob, which only affects the intensity of the high freq spark.

It does not change the welding frequency - it is 60hz only.

Heh I always just left it set at 100. Learned something new

Why would one need to change hi freq intensity?