MIG Welders

[Georgia Flash]

I found this thread by doing a search so here we go guys lets start this sucker back up again!

No one answered the one guys question about the Campbell Hausfeld welder. I too have bought one of these except mine is the $299.00 version with the optional gas hook up.

Now the question I have is this. I tried to weld in a piece of sheet metal to cover a hole in the floor board and literally burned a hole through my existing floor and the sheet metal.

I had the welder set on the lowest setting that I could and still this happened. Whats going on here and what should I do? Please do not say just take it back and swap it! I need input input input

[Guest 400 ci 280z]

also any comments about century welders too

[Dave]

Were you using gas shielding and .023 wire?

 

Dave...

[Georgia Flash]

Nope, flux core and .35 wire

[Georgia Flash]

Also, how close do you put the tip or nozzel to the piece that is being welded? The owners manual is unclear about this. They say while tuning the welder you should "drag" the nozzle across the piece while adjusting the wire speed with the other hand. Is this to say you actually touch the piece of metal with the tip of the wire welder?

[jeromio]

Thick wire and no gas. This presents a big problem with the extremely thin sheet of the Datsun. If you have the dollars, I would strongly suggest getting a bottle of gas. I got the medium size tank for about $110. You also need a regulator and the welder must have the solenoid and plumbing (which you mentioned it had).

 

With the gas, you can run 6mm wire which doesn't arc as hot. Even then, you'll need the low setting and some finesse. It is possible to get decent results with the flux core, it's just harder to do.

 

Touching the actual welder tip to the work is a bad thing. Try putting the tip about an inch away from the metal. Start with a slow speed. You can move closer and also turn up the speed as you get things going (and not burning thru). If you're patching, put some new metal down with a good half inch overlap. What I've found works well is to weld thru the thin metal onto the new metal. But even then, you'll need to pulse the trigger. Otherwise you end up disintegrating the old metal with holes. Heat distant spots, in short bursts. Work back and forth. It takes practice. Once you get a pool of molten metal, you can grow it and move it. But you have to be careful, because it can get too heavy for the surrounding metal and plop off leaving a hole. With experience, it is possible to weld over a hole - even a large, quarter sized hole. But, generally, once the hole (and we're only talking good metal here, if it's a rust hole, then you gotta cut out a big piece until you get to only pristine metal) is dime sized, you really need to patch it with another piece of metal.

 

I recommend practicing with some thicker, more forgiving scrap metal. Try welding some stuff together, and then cutting thru the weld. Then examine the cross section and see how well you melded the too pieces together. It's very common to have what looks like a weld, and sort of holds together, turn out to be 3 fairly distinct layers of metal - the 2 pieces to be joined, and a loose bead. That's not good. The goal is to get the bead to lay flat, with no bulging. You want to burn thru and melt the two pieces, using your welding wire as just a medium to transfer the heat that you need to the 2 pieces. Then, when you cut thru the result, you can't really tell where the piece transitions to weld.

 

Oh, and please disconnect the negative battery lead and also disconnect any sensitive electronics (ignition modules, stereo, ECU, etc). And if you buy sheet metal to use for patching, don't get anything zinc coated - poisonous fumes that ruin your day by making you dead .

[Georgia Flash]

Thanks Jeromio,

I have two old car hoods to get some metal from these wouldn't have the afformentioned zinc coatings would they? One is off an 80's Chevrolet Caprice and the other is from a small Chrysler product. I have been thinking about getting the gas canister hooked up to my welder and may well do it now.

Again thanks to all for the input

[Pop N Wood]

I have century welder. Sorry to hear others have such a low opinion. Mine is a 220V, 145 amp DC unit. I got it close out at a SAMS club for something like $300 about 4 years ago. I have had zero problems and it seems to do everything I want it to do. Being 220V and DC means it is not exactly an entry level so maybe the quality of this model is a little better than the ones in the Sears catalogs? Of course I have never heard anyone say a bad word about a Lincoln or Miller so that says something.

 

Would like to second all the talk about getting a gas version. It is a little more money up front but cheaper in the long run due to the more expensive flux core wire. Also the smoke from the flux core wire is a killer. Harbor Freight Tools is a good source of cheap bottles. My brother welds for a living and swears by just straight CO2 for mild steel. He got a used CO2 bottle from an old vending machine place for about $15.

 

Also, as a fledgling MIG welder myself (I am a killer with a torch), I find getting decent welds in sheet metal is more of a graduate course than beginners. Once you burn a hole you have a problem. I have had some success filling them back in by doing short, 1 second burst just to build up metal around the edges of the hole. Once the hole is kinda goobered over you can weld through it to get a pretty weld again. Keeping everything clean (no paint or rust in the weld area) seems to help. Switching the polarity of the welder (positve to negative) seems to help but I can't remember which way worked best.

 

One other comment about wire. My century manual says wire should be thrown out if it is left open for too long...even the copper coated stuff...or it won't feed right. I am too cheap for that so I always buy the small spools. I have noticed older wire does slip a little more causing the weld to stutter and pop. A killer when you are working on sheet metal.

 

What is everyone's opinion of AC vs. DC welders? When is one better than the other? Also I have heard that welding on a car with a computer can kill the computer. Is this always true and what exactly needs to be done to prevent damage? Remove the computer?