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Inkomodius · 10-22-2008, 05:27 PM

True! MIG welds are very hard and brittle. Any time I tack pieces together for slip rolling with a mig, they break if there is any deflection. Where as 7018, or TIG welding them provide a more maluable weld. I also learnt this from doing auto body, tack it with MIG then try to hammer form it, it cracks every time. Also if the vessle is a pressure vessel, I have never seen anyone use MIG to build them up here and up here all we do is pressure (mostly) because MIGs have a cold start and dont get full penetration off the start which usually leads to pinholes. Stick and TIG you can use your arc to preheat before applying filler metal.

10-22-2008, 05:27 PM	#2 (permalink)
Inkomodius Member Join Date: Sep 2008 Location: Grovedale, Alberta Posts: 28	Re: Interesting Welding Statement. True! MIG welds are very hard and brittle. Any time I tack pieces together for slip rolling with a mig, they break if there is any deflection. Where as 7018, or TIG welding them provide a more maluable weld. I also learnt this from doing auto body, tack it with MIG then try to hammer form it, it cracks every time. Also if the vessle is a pressure vessel, I have never seen anyone use MIG to build them up here and up here all we do is pressure (mostly) because MIGs have a cold start and dont get full penetration off the start which usually leads to pinholes. Stick and TIG you can use your arc to preheat before applying filler metal.