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MG MGA - 110V Spot Welder

I just bought a new 110V spot welder to start my inner rocker replacement. I have been practicing on scraps to improve my skills. After about 2 welds my breaker pops. Can anyone suggest what size breaker I need? The 20 amp ain't working
Thanks
Bill James
WRJ JAMES

Bill, I use a 240 volt spot welder and it frequently blows the 13 amp fuse. So assuming it's a similar welder apart from the voltage I would suggest a minimum of 30 amps..................mike
m.j. moore

I used a cheap Chinese 115-volt spot welder extensively a couple years ago. My shop has a 230v remote service box and very good electrical wiring, all 12-gauge (20-amp capacity) and 20-amp circuit breakers for (15-amp) wall outlets. When making lots of successive spot welds it would occasionally pop the circuit breaker (after a dozen spots perhaps) but only rarely, like maybe once every 500 spots or so. I used it on a couple different circuits (different breakers) and it worked as well on either one. It only blew the breaker a few times in my entire body sill project.

Thermal circuit breakers may have a "blow current" range of +/-20%, are temperature sensitive, do get hot with continued current draw, and they are not all exactly equal. You could try replacing the circuit breaker or swap it for a different one to see if that helps. Also suggest you do not plug a drop light into the same circuit while you are welding. The 1-amp draw for the light might be the difference between blow or no-blow on the circuit breaker.
Barney Gaylord

Hi I have no idea of your set up. What ever you do do not change fuses up. Find out whatever is on the same circuit, and turn it of. I had similar problem of not having enough power. I solve it by runing fat extension from 220v dryer plug, using only one side of the 220 to get 110. Just do not use the dryer at the same time. Ask an electric friend for advice, electricity is dangerous to your health/shock and property/fire
Martin
m zazvorka

It should say what size breaker is required, perhaps the welder is faulty. What ever you do don't over breaker the wire. To up-size your breaker to a 30amp, wire size need to be 10 gauge.

Bruce
B Suelzle

Some people have been known to put a small fan on the breaker box for extended welding sessions. Works fine, especially if you take the cover plate off the box so there is good air circ through the works.

However, you should not be having problems after 2 welds; check the contacts and connections in the box to see if anything is getting hot. Remote IR gun is excellent for the job. Check the welder nameplate to see what it calls for, and if it still blows with the correct breaker, find the problem. It is not unusual to discover a problem that was going to burn the place down next week without the welder. I found a bad main fuse pullout that was heating the circuit fuses. The wall was charred behind the box pullout area, but I had never blown any fuses before.

FRM
FR Millmore

Hey folks, it now appears that I will be in the market for a welder to restore the lower sill area on the rusty 1960. Any advice on what is the best approach for a novice?

Hey FRM, how is your daughter doing in college? REGARDS, Tom
Thomas McNamara

Thanks for all the help.

My house is only 4 years old and up to code, so I didn't think I would have a problem. I Plan on Going with a 30 Amp with 10 guage wire on a Dedicated outlet. I'll run the spot and Mig off that outlet.

Thanks

Bill James
WRJ JAMES

Never assume that ANY trade did its job correctly especially on a new house. There are just too many people trying to cut too many corners.
Is there a plate on the welder specifying current requirement? If so what are your requirements?
R J Brown

Bill, how long are you taking with each weld? I have the HF 230v unit but it seems to weld find with no more than about 2 seconds of weld time. I also let it rest at least that long between welds and after about a half dozen welds I let it rest for at least 30 seconds to cool down. These low cost electrical tools are very sensitive to overheating which will break down the insulation coating in the windings and short them out so keep them as cool as possible.
Bill Young

I'm still perfecting my spot welding skills. But I think less the 2 seconds a weld seems to produce the best results. I installed a 30 Amp breaker on 10-3 line right at the panel. All appears in working order.
After a few more practice welds, Im ready to start.
Thanks again for all the insight.
Bill James
WRJ JAMES

Thomas,
I have a small MIG: Lincoln SP-125 Plus. It runs on regular household current and has been very satisfactory. I have built two cars up from “basket cases” with it. Be sure to get yourself a helmet with an auto-dimming glass, it sure makes live a lot easier.
David Werblow

As has been said DO NOT, what ever you do, just change the breaker for a larger amp size. If you do do this and get luck, you will let the smoke out of the wires. If you are not lucky you will let the fire out as well and then you will get a new house.

The spot welder should have plate on it to indicate the amperage requirements. DO NOT plug the welder into a circuit that does not meet those requirements.

Also the distance you are from the voltage source (i.e. the panel) does make a difference, as voltage does drop the further you are away from the circuit breaker. That is why larger diameter wire is suggested. Use 10 or 12 gauge instead of 14.

Jim
JP Jim

There is a substantial difference in output current between 115v and 230v spot welders. The 115v unit is obviously power limited when it is built with a 115v 15-amp power plug and cannot (or is not supposed to) draw more than about 15 amps from the wall socket.

My experience is that the 115v welder takes about 4 seconds to make a very good spot weld on two layers of 18-gauge steel (.048" thick), slightly less for thinner metal, longer for thicker metal, a second or two more for three layers of steel. Given enough trigger time to heat the spot, it works perfectly well, just slower than the 230v unit.

When you make a good test weld, then separate the sheets with hammer and chisel, it should tear a hole in one sheet rather than splitting the weld joint. If you don't get welds the strong, you need more trigger time.
Barney Gaylord

Don't up the breaker size...something else is wrong here, and that ain't it. I have a cheap-o 110V welder that works just fine on a 20A breaker even at relatively high duty cycles.

Some thoughts:

Are you using an extension cord?

Is the garage outlet a looong way from the breaker (mine is in a subpanel in the garage about 20 feet from where I plug the welder in)?

20A breakers should be feeding the outlets with 12g wire, not 14g - so if your garage is up to code and relatively new, the wire feeding the outlets should be yellow, not white.

Is the breaker a GFCI?

Welders have voltage settings - mine has four. I almost always weld using "one" or "two". The higher voltage settings are too hot for thin metal, but I have used them for welding on the frame (no blowing breaker though). Try practicing using the lowest setting and adjust the wire feed speed - make sure that you are getting wire stick-out of 1/2" or more.

If you are using flux core, make sure you have polarity set correctly inside the welder (opposite of gas fed).

Lastly, read the instructions or on-line help for your welder's manufacturer to see if there is something else that might be amiss, or how to troubleshoot it. Welders have a large copper or aluminum transformer internally. If it is open or shorted, that could result in high current draw and improper operation. This can be checked easily with an ohm-meter.

JIM in NH
AJ Mail

What Jim says.
I had attempted to weld a new radiator support on a Festiva several years ago with a 120VAC mig welder. I couldn't get a clean weld, or much of any for that matter. My buddy said, "You need a welder." I responded, "I have a welder" and pointed to my mig welder, to which he responded, "You have a welding machine. You need a welder."
We got a welder and he couldn't do the job with my welder either. I had to take it to his house.
Later, I built a new garage and replaced the electrical. I found that I only had 14 gauge wire going from the house to the garage. Now I have 2 gauge. It won't happen again.
Mike Parker

This thread was discussed between 24/01/2010 and 29/01/2010

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