I am new to this forum, but have seen many questions and comments regarding welding as I have read through the archives. I am a welding instructor at a high school and applied tech school in Utah (19 years) and welded professionally before I began my teaching career. Most of the welding that we need to do on these classic ponies can be accomplished with the GMAW(also known as MIG) process (bodywork, floorpans, framerails etc.) One thing I tell my students to do on very thin material that I think may help some of you is to NOT try to weld long continuous welds. Rather, use short welds (spot welds if you will) to weld in floor pans, fender patches etc. Use the smallest wire available such as .023" or .030" though I typically use .035" . You want your voltage set fairly high so that the weld adequately fuses to the base metal. You then put the end of the wire in the weld joint and squeeze the trigger for a brief moment, around 1 second. Then move just beyond your "just deposited weld" and repeat. The high voltage will give adequate fusion, and the "spot weld technique" will keep the base metal cool enough tho avoid warpage. If the wire bounces off the plate (called stubbing) the wire speed is too high or the voltage is too low. Also, you should use an ER70S-X wire, the X being a variable, typically 2 or 6. Do not use an E71T-X wire as it is a flux cored wire which runs much hotter than the "S" or solid wire. Straight CO2 gas causes the arc to burn hotter, whereas a C25 gas (75% Argon, 25% CO2) burns cooler and typically gives a better weld finish....shiny with little cleanup versus satin finish and more glass (brown deposits on the weld)
This technique also requires very little welder skill...so easy a high school student can do it! Hopefully that helps some of you who may be unsure about this whole welding business and allow you git-er-done.
Gordon

 

Thanks for the tips, will probably put this one in my file. There are some projects that I am seriously considering buying a welder and trying to tackle myself. However, the local car club is trying to arrange a class with a welding teacher at the local tech college so I am waiting to see how that pans out prior to jumping in with both feet.

 

That's the most informative post I've read in a long time. I used to stick weld on Semi truck trailers to repair damage, and have used ARC welding techniques in machining, but never have used a MIG. My neighbor has offered some of his experience but he's totally hands on, and can't explain most of what he does and why it works.

 

i agree, that is a very good explination for a person who has never been around MIG welding.

 

EXCELLENT INFO!!!!!!!
im looking into doing some welding and you just saved me a lot of time
thanks

 

i think this should be stickied

 

Excellent info. thanks for the clarification on the C02 versus 75/25gas mix.

 

yes, sticky!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

its good information for beginners.

but its something that is just learned automatically when just goin out and doin it. i learned and taught myself at age 17. i replaced all the floor pans and MANY MANY other pieces and parts on mine and my dads mustangs.

 

Teacher your right on, your 1 second rule would depend on the equipment. for example the newer low end machines 110v. millermatic 140 yes 1 - 1.5 seconds, Lincolns 140 3 seconds. considering the voltage for 220 again 1 second for the millematic 180 and 3 seconds for the Lincoln 180. Why? the quality of the circutry. of cource this get compleatly reversed with other generations sucha as the MM135 amd the lincon 135 and Lincons 175/mm175, dont even try this with the harber freight, home depo units they dont compair. my credentials - distridutor for all welding equipment mfgs for 13 years, each generation is different and each mfg has there own claim to fame. Outstanding post