MIG???

The limitation of the 110 volt machine is the maximum thickness they will join. The better 110V machines top out at around 3/8" thick (C steel) material. Welding material of that thickness also requires the machine to operate at full output. This means that you will weld just a few inches before the thermal overload protector kicks the machine out. Typically we are talking about a bead around 8" long at the most before the machine stops. That can drop to around 4" after it trips the first time.

You may have better luck with the stick welder if you try pushing the rod instead of dragging it. If you have been dragging you will notice a remarkable improvement by going in the opposite direction. Burn-thru will be reduced significantly. A 3/32" rod should work OK for you. Use one designed for sheet. (6013 is one)

There are also chemical aids that will benefit someone who welds thin material. A tube of heat fence (fits a standard caulking gun) is designed to apply a bead of heat absorbing material right next to the weld area. It will prevent warpage on thin sheet metal and is often used when welding is to be done in close proximity to a rubber windshield molding or other heat sensitive material. It need only be applied to one side to be effective.

In regard to machine choices there are many to choose from. Go with one of the major brands if you really want to buy quality. You won't regret spending a bit more.

We are soon going to be offering a machine formally manufactured by Miller of South America. It's now called Comparc and some will be offered as a MIG welder with a built in stick welding capability. Some machines are going to be combined with plasma cutting capability. The price will be very competitive as well. You can expect to see a lot more competition in this field in the next few years.

If I can answer any questions in more detail please feel free to e-mail me directly.
Steve

One way of cheating when welding thin metals is to use a copper or brass backer plate. I have some bar stock of these two materials from 14 gauge thick up to 3/4" thick. The thicker and wider the higher the cost too and this stuff ain't cheap to start with. I'd say for what you are doing and nice piece of 14 or 12 gauge copper about 1' long and 2" wide would be sufficient. This is easy to bend and match to the shape of the piece you are working on and won't empty your wallet. Shape it to the back of the weld area and clamp in place. This will help transfer the excess heat out of the work and also aid in keeping you from blowing holes in the weldment. A real cheap way to get a copper backer piece is to flatten out a piece of 3/4" or bigger copper tubing and use that instead of buying a special piece of bar stock.

As for the mig machines, go with a gas shield wire of the smallest diameter you can get like .023" This requires much less voltage and amperage to run and will put less heat into the weldment. The smallest flux core (non-gas shield) wire I have found is .035 and this will weld down to 18 gauge if you're real good with a welder, 22 gauge if you're real show off. .023" solid wire will weld down to 30 gauge without requiring a whole lot of skill. The trick most often used is doing a series of small spot welds rather than trying to run a steady weld bead.

That Cu back-up sheet works good on Al welding applications too.

We have the open-arc wire in .030" and it does weld sheet metal fairly well. Not as well as solid gas shielded wire though. A large part of that is due to the polarity the self shielded wire operates on.

What I have always liked about a good self shielding wire is how it complements the smaller machines at maximum capacity. They are not all created equal, as I know you are aware.