Bigvic

I am in the process of building a new shop which is a pre-fab bolt together kit. However, I am adding on a lean-to carport on the side of the building. I am planning on welding my rafter purlins onto the building's eave strut where they will travel down matching the roof pitch to be welded on top of 4x4 posts at the other end. On top of these I will place my cross purlins which will take the roof tin on top of them.

At first I was planning on renting a gas powered stick welder (no elect. on property yet), but then I started thinking I could save some money by borrowing a small generator and using my 110V MIG. It is an 80 amp CH gas mig. I am just a little worried about using this welder for structural members...especially since I will be on top of these purlins when I put on the tin.

The welder says that it can handle 12 ga -3/16" and IIRC the purlins are 14 ga. So will this welder work for this project? If all else, I guess I could come up with some brackets or plates that also incorporate bolts for insurance.

Any thoughts?

cbrich

You can use your MIG welder outside but there has to be absolutely no wind, I mean no wind at all, unless you use a flux core wire. Your best bet would be to rent a gas powered stick welder.

Nine Ball

iTrader: (38)

use the MIG, but go with a flux-core wire instead. The welds aren't as "pretty" but the penetration is better on the thicker stuff. Plus, you won't need any gas.

67RSCamaroVette

iTrader: (63)

when you weld with flux core, keep the wirebrush next to you (i like a wire wheel on a cordless) and brush the weld EVERY TIME that you stop. Don't get lazy and stop and start again, it's easy to do but will just turn out really bad. You need a clean surface to get a good spark, if you don't, it will spatter and drive corrosion down into the metal, then you'll spend more time trying to clean it up and fix it than you would if you just cleaned it first.

I'd gusset the beams, too, if you're worried about weld penetration.

Bigvic

I decided to use my welder in conjunction with some gusseted brackets that will basically make the whole ordeal a bolt-together affair that I will also weld together.

Thanks for your replies.