stitch welding with Flux core...yeah I know...

[mugendork]

Alright, I am debating. I have access to 3 MIG welders...gas-less... I want to stitch the interior before I shoot paint. Right now all I have access to is basic flux core gas-less mig units. Has anyone done it with reasonable results. I don't care if I have to clean up the welds with a grinder later, my only concern is the quality of the weld. What are your guy's thoughts?

[EJ253]

whats the amperage on the gasless migs?

i dont know much, but i would say use ~140amp, body sheet metal is about 18 gauge i think
but who cares if you get a little spatter, i wouldnt grind the welds later, that seems like you could easily mess up a perfectly good seamwelding job by adding unnecessary heat which could possibly warp it or comprimise the structural integrity of the spot welds

any one can correct me if what i said is inaccurate, im still learning too

[luisgonz]

Dont do it looks like shit on a donkey dick.LOL hahahaha Use gas for god sake. Dont be cheap.

[donkayroo]

140 is way too hot and will burn thru...penetration will be fine if that's what you're concerned about. 90 amps is still too hot but the majority of cheap Kragen, Harbor Freight, etc flux core migs are 60-100amps so that's what you'd have to work with. If you're desperately set on fluxing you're seams go with the lowest setting and work slow enough for good penetration but fast enough so you don't burn a hole in the sheet. It'll burn thru easier than you think if you can't go as low as 30amps.

Function over form...but if you don't have welding experience now is not the time to practice. Have someone with experience do it or at least teach you. The welds will look really ugly no matter how experienced you are. If the metal ain't cleaned to it's bare bones, it ain't gonna be a great weld.

No offense, but it seems you don't have much experience welding. Ask the guys who are loaning you the welders to give you pointers.

To be honest, you really should get some practice time on similar gauge metals before you even attempt to touch the electrode to your chassis. Read some welding books if your pals don't provide detailed instruction. At least with books you can take them to the crapper with you...or your laptop.

Get scrape metal and weld the crap out of junk pieces so you get a gist of how to set the correct amperage and wire feed. Burn thru pieces, mess with wire feed speeds, play with amperage settings, all on similar metal you plan to weld.

A flux weld can be as strong as a shielded gas weld (depending on the application) but only if you stay within the optimal heat range, practice rule-of-thumb welding etiquette, use the proper handling techniques, blah blah blah.

My buddy and I used a cheap-o Harbor Freight flux MIG and had awesome results fab'n downpipes, exhaust systems, sheet metal, bumper supports, intercooler brackets, etc. despite the rancid ugliness of the despicable porcupine splatter. We're sick of the ugliness and hassle of the smoke, splatter, flux dust...so we're getting a better welder in the near future. The splatter is sharp and will scratch the crap outta you if you're not careful.

Good luck. Overall, you can get the same rigidity results if the welder knows what he's doing. It'll just look super ghetto. Petroleum jelly may help mask the areas you don't want splatter. But when the metal heats up that stuff can liquify.

[Jung918]

Flux actually runs hotter then soild wire. I dont see anything wrong with it as it does the job.
I would say not to do it yourself if you are new to welding. Even if you get some practice on scrap pieces, it takes months if not years to master it. It isn't just simply melting to pieces of metal together. There are many other factors that can play a role in how well the welds come out.

If you choose to use flux core, I would at least run a flap disk or a wire wheel afterwards.

[mugendork]

Thank you guys, your input is appreciated.

[S14DB]

With Flux core welding you need more control to get a very smooth wire feed speed. Cheap units won't have good wire control which will ad to the problem.

You will have 2 major problems. Slag or FUD in your weld and Bubbles.

Slag comes from the fact that it is hard to get a good gas envelope from flux. Always starting will be messy cause it takes time for the envelope to form. The weld will be uneven due to the envelope waxing and waining.

Bubbles are going to be the real pita with the sheet metal. The gas formed from the flux will not bubble out of the weld fully if your power is wrong and you go to fast.

This is far from ideal in automotive applications. Especially stitch/seam welding. You will not spend enough time to create the envelope. The thin metal will not leave much material to grind away the slag and bubbles.

-Don't flux anything thinner than 20ga.
-Don't flux anything that needs to be finished/painted
-Flux takes much more skill then MIG as the tolerance in the settings is more critical.

I would not recommend flux for your application as it will look like your car has herpes.