What is the Best Amperage for a Wire Feed Welder

By DaveSisk Date 07-09-2002 02:23

Hi folks:

OK, another question. Most 115V wire-feed welders seem to top out at around 85 - 90 amps. If I understand what I've read correctly, the amperage can limit the thickness of material that you can weld on ONE PASS, not necessarily an ultimate limitation. Is this correct? For instance, a 115V 90 amp welder could weld 1/2" thick steel plate, it would just take multiple passes to do it. Is this right? I'd assume you would grind out a V-shaped groove and then fill this in using multiple passes, right?

Or, do I have this totally wrong, and you simply can't weld 1/2" thick steel plate with a 90 amp welder period?

I'm trying to figure if I should run 220V power into my workshop, or if 115V is sufficient. I'm not that interested in high productivity and welding speed, I just want to be able to get a decent quality weld with a good appearance and minimal spatter. I'm not welding aircraft frames here, just some "wrought iron" furniture and maybe an occasional tractor attachment...<g>. I'm thinking about upgrading to a MIG welder from my FCAW-only welder, and I'm trying to figure if I really need a 220V/100+amp unit, or if 115V/90amp unit will be sufficient.

Thanks for all the previous answers!

Dave

By Goose Date 07-09-2002 03:01

I've owned two small 100 amp Mig welders in the past. The first was a small 90 amp pocket Mig that was a piece of junk. The second (I just sold it) was a Century 105 amp unit that was a nicer quality. These machines are really limited to light sheetmetal IMO. My Century would weld 1/8" steel, but the bead stood up and would not lay down nice telling me that the voltage was too low for complete penetration.

The projects your working on are thicker material which dictates a larger machine. Multiple passes might accomplish your goal, but the appearance will be sacrificed which I assume your furniture would require.

I'd say you really need to wire your shop for 220v. The 220v machines have higher outputs which is what you need. I'd say you should really consider investing in a unit with a minimum of 150 to 175 amps for your projects. Think of how long you'll own the welder to see how investing more now will pay off in the long run. A cheap/small machine like I had and then have to sell/upgrade costs more in the long run. I refuse to do that again...

I myself am currently buying a 250 amp Miller/Lincoln Mig so I'm not limited with future projects.

By dee Date 07-09-2002 22:51

Dave
Personally I would hold out for a 250 Amp or more gas shielded wire feed welder, and here's why:

I am a proponent of spray transfer for flat welds and use it whenever I can. The hot, fluid weld achieves deep penetration. Fast. I traded penetration and occasional lamellar tearing issues for control of that heat, and personally prefer it that way. Its worth the additional expense in equipment and time to adapt to the differences, in my opinion, as I apply it to my work on steel 1/8" or thicker.

My shield gas is about 80% (or more) Ar with balance CO2 and it is considered an all purpose mix in respect to modes of transfer... 25% CO2 is too much for a stable spray at parameters you may expect to achieve without a 3phase or engine driven model.

If the gas becomes an issue- I had a little struggle finding a ready supply for it-there is nothing wrong with going with the crowd, running 75%Ar/25%CO2 and staying in short-arc... you will still be glad you have the power when you consider duty cycle and how many multiple pass welds take how much extra time. I dont have the time to weld three beads where one would have sufficed and wait for the power supply & gun to cool down as well at < 20% duty-cycle at that [maximum] output.

I can always find a use for 220 V (50A or better) in my shop if I look hard enough, but If I were allowed only one machine it would be a stick welder (after OxyAcetylene if that counts) for its inexpensive versitility.

People buy and use those small machines all the time. Very satisfactory welds are created with them daily on thin # material. I considered a Miller at about 185 Amps but yielded to the thinking I described.

I found it to be an understatement to say the decision required consideration of many details, and suspect you now have food for more thought.

Good luck with your choice
D

I agree with these guys completely, in wire feed there is no substitute for power, even on thinner metals. 175/185 minimum, but you still may occasionally be looking for more. 250 will satisfy any of your needs, hold up well, and retain it's value if you ever want to resell it.

By stich585 Date 07-10-2002 01:47

Hello Dave. I would like to give you my two cents. From reading your questions I gather that you are needing different welding applications. In my opinion 1) You need to wire your shop for a 220v machine. 2) Quit looking for one cheap fix all and purchase the proper equipment. ( Most welding outfits will lease equipment reasonably priced.) I Would suggest narrowing your search down to finding the proper power source for your needs. I.E. M.I.G. unit with an optional push pull gun for AL or a ARC machine with high freq., T.I.G. torch and stand alone wire unit. The last in my opinion is your best bet. it covers all of your basic welding applications.
I know that it is frustrating to hear but in the end the aggrivation you save will be worth the cost.
Oh yeah, if you are just doing this as a hobby, concentrate on one thing at a time. Don't jump into aluminum until you have mastered carbon steel.
One more thing, when wire feed welding forget about amps and concentrate on volts and wire speed. This will help your penetration and fusion questions.

By dee Date 07-10-2002 18:59

Stitch,
I must conceed your point re TIG it is a process I do not use and smtimes regret lack of qualifications on it but offers overall superiority in nearly any evaluation

I think we should remember we stepped Dave's original budget up from 500 bucks to 1500 or more without spoolguns etc a point arises where it becomes cheaper to bring the stuff to a weld shop as more cost effective; payback on investment is a valid consideration. I thnk leasing is a good option we all forgot; it also gives chance to try the equipment and gain some experience and a point of reference for final decision. The idea is great.

I disagree, however, about finding a cheap fix; farms and many shops have been getting by with stick welders or a set of tanks and torches for ages. Dave aint gonna be weldin spaceships in that garage.

OxyAcetylene flames fired the entire industrial revolution and are a capable tool in trained hands- possibly available at the cost of wiring in the 220 V. no longer needed for it.

A GMAW spool gun, in contrast to a push pull, is fine for occasional use and offers convenient, small, relatively cheap wire spools of many alloys to suit unusual needs incl. aluminum, albeit at a somewhat heavier weight. Dave could easily match his equiment investment with the cost of various filler wires in 10lb spools; spoolgun spools are 1lb.

I too sense Dave wants a welder that is versitile. TIG is certainly top shelf, but there are alternatives. I have utilized them for many decades and continue to survive. Frankly I am thinking GMAW is overkill. Overkill can be nice to have and is more convenient than struggle, but tell that to a guy with an NO2 injected Chevy 350 engine driving his weed-wacker.

IMO: Rental idea certainly is the right start point.

Regards,
D

By RonG Date 07-10-2002 21:03

I have no idea what your application is but you should be aware that in many instances a good pre heat will do more than the most powerful welding machine made.

You need to look further than just the thick ness of the material.
Not trying to discourge you from getting a better machine.

Think in terms of heat sink. If the mass you want to weld can dissapate the heat faster than your machine can produce it try helping it along with some pre heat.

johnsonfrated73.blogspot.com

Source: https://app.aws.org/forum/topic_show.pl?tid=2464

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