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DeathBlade556
01-27-2009, 07:10 PM
Well I got tapped as the welder for RMUs mini Baja car we have some 4130 1" OD 0.120 &0.049 tube for the frame. I tried to use RMU's welder which is a 220volt Lincoln with ER80-D2 and 75/25% argon/co2 and I couldn't get it to lay a bead for shit,(something is wrong with it I guess) so I had to get my 110v lincoln with some ER70-S6 and 100% Co2. With mine I could lay a good bead. But the problem is is there any problems with using 100% co2 and 4130? I know ER70-S6 and ER80-D2 are both wires for 4130, and ever other board/source saids 4130 should be TIG welded not MIG. So any hints?

MF Steve!
01-27-2009, 08:13 PM
This question would probably be suited well for conversation on offroadfabnet.com Not to say there aren't a few people here that can answer the question, but about 50% could probably answer it over there.

cody
01-27-2009, 11:11 PM
regarding the lincoln 220 machine make sure you polarity is dcep meaning electrode positive. if the machine was setup for an innershielded wire then it would be set for dcen . i weld 4140 , ar 400 , t1 all bieng considered hard metals. the trick is preheating the work before welding and a slow cool down period , so no dunking it in the water .

DeathBlade556
01-28-2009, 09:08 AM
Ya, its got positive electrode checked when I went to see what wire they had in it. Doing a bit a research into it, on the lincoln they use A-D(on mine 30-100amp) and A-I(on RMU's 30-180amp) I could get a better weld on mine at D 100 amps then I could get at G on theres approx 120amps so there must be some thing else wrong. And not quick cooling it, Preheat would be a problem they dont trust us with blow torches, they will let us use lathes that could rip our arms off or welders that could electrocute us, or robots that dont have working laser shields so you could be clubbed in the head by a half ton of servos, but god forbid we burn our selfs with a blow torch.

wozz
01-28-2009, 07:25 PM
im no help on the welder, but 0.120 seems really thick for the purpose.

DeathBlade556
01-28-2009, 10:34 PM
Thats the minimum wall thickness for the roll hoop. SAE has some crazy things in the rule book.

wozz
01-28-2009, 11:18 PM
hmm I honestly haven't read the book lol, I thought we used thinner


Ok It looks like it just has to have the same bending strength and stiffness of 1018 "1inch od .120 so it doesn't have to be .120