Chances are the guy at the supply store is just a salesdork. He just knows what he hears. Listen to your instructors. Try it and you'll probably be going to one bottle too. The guy who taught me to weld would not allow mix in the shop!!!! Only straight argon. Try the same psi setup as mix (I use 18 psi) and go up or down and see if you can find the best setting for your torch. The regulator that come with the "home use" mig machines aren't that accurate. When you find the lowest setting that works, mark the gage with a Sharpie and your good to go.
nothing worse than contaminated welds..( except for cracked or broken) porosity and weld contamination is what you will be asking for, not welding clen steel can lead to bad penitration, and possible falure of the weld.
Brak-cleen works great on sheet metal where an excess of flapping beats the shit out of the steel. Make sure chase your wet rag with a dry rag to wipe off what little white sediment is left..... Repeat after me, welding is FUN!
I try to treat the weld area as if I was going to paint it. By that I mean, I clean it with the flap or grinding wheel and then wash it with degreaser or surface prep, something that evaporates rather quickly. This process takes off the obvious rust and paint and the wash takes off the oil and other "unseen" contaminants. Works for me. The mig is very particular and won't weld unless the metal is clean. It's like a built-in test that if the mig acts up, the area isn't clean enough. A problem I've run into lately is the area that is pitted and has recess in it making it almost impossible to get those little areas clean. How do you guys get that stuff out and get the area clean? Thanks
Blast it with media (whatever you have) try to work a small CLEAN spiral wire brush into the recess then wash it out with brake cleaner.
If you guys invented it - we sure bought a bunch of it here in Michigan!! Anybody who has been "low man" as a tech in a body shop in a place like Michigan has learned (some the hard way) to get 'er shiny 'fore ya weld er up. Some like to think you can cook out the impurities, but why use all that heat?? Grinders are for cleaning, torches, arcs and migs are for welding. Just ask yourself - whats gonna happen when this breaks?
Hey Dusty, want some more rust? I got a whole bunch of it swept up in the front of my garage. Free, you only pay the shipping!
Kevin,,you are right about getting the surface down to clean metal,,,yeah,,,everywhere you touch it and the humidity over the time it takes to finish all the welding,,,yeah,,,you are going to have to do some more cleaning ie. sandblasting,soda,walnut or flapper wheel,,, That's just part of the process,,,at least the way I do it! HRP
I weld and fabricate for a living and have done for a long time. This is interesting reading from some guys who know what its about. Isn't it funny that some who don't know will disagree with you. For the guy who uses brakeclean, I sometimes use methlylated spirits for stuff that will be tigged, including the filler wire. I think in the USA it may be called denatured alcohol??? Off topic alittle, and not recommended for your automobile, but for maintenance and repair work, where clean steel is not always possible, you can purchase consumables that are more tolerant of rust, paint or dirt, etc.
It's shop policy here to have your car completely blasted before any thing else. I then decide if I have enough time to do the needed repairs (welding) right away. If not then its DPed as soon as its vacuumed and blown off. I use clean dry air and a new scotch pad to lightly scour and dust off the surface. Afterwards I use a slow degreaser... When I was still in the "hell" of collision body work I saw many welding no-nos. The one that sticks out the most was when a hacker welded on a frame section to a still rusted and undercoated frame. The car drove off and later collapsed. Before any one jumps on me...I tried along with a few others to bring this guy to the attention of the boss. As with most collision shops the "dollar" won out and this guy still works there. The hacker makes the boss so much money, that it was cheaper to buy the customer a new car than to fire the cash cow! And this was in a big name dealership here in Dallas...
I am qualified to say after 8 plus yrs. in welding in all phases & conditions you guys are leaving something out . My boss was an asshole when I first started in one shop & he always said make the parts fit tight or you F'n fired, you got that ? So may I say that in a lot of situations you got to clean like a doctor AND fit the F'n things right GAS,TIG,MIG it don't matter. Clean & tight. Sounds good don't it?
I didn't always clean the metal in the past, but it REALLY does make a difference, AND makes you a better welder. Blasting, grinding, or even wire brushing can do the job. If you are panel welding, dont forget to clean the BACK of the surfaces to be welded (they can be a bitch to reach) but the back surface can pollute the weld just as quickly as the front!
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