Using cut off wheels to grind welds

[chevynut]

Sure, weld two pieces of sheet metal together, grind them flat to form "one sheet", and then cut through the weld area with some tin snips. You'll know exactly where the weld is.

That wasn't really my point Robert . I do believe the ER70S-6 wire might be harder than the sheetmetal. It is probably alloyed differently.

But what I wonder about it why a TIG weld with ER70S-6 rod would be any different than a MIG weld with the same wire. Have you done the cutter test with a TIG welded sheet? I'd sure like to see some hardness testing done to prove or disprove that claim. I'm sure a TIG fusion weld would be different than one made with the rod.

[567chevys]

I think many people's problem with Mig is that they are reluctant (skeered) to add enough heat. I have always adjusted the heat for full penetration welds first and foremost, then adjust wire feed to prevent blowout, then control weld size (heat applied) by duration of trigger pull. IIRC, the -7 welds above were with the machine set at the factory recommendation for 16ga steel, even though the panel is 19ga... I also did similar welds with the machine set at 3/16" steel heat setting, and trigger duration was less than 1 second, and absolutely NO BLOWOUT. It was just something I was playing with the see what worked best. I'd suggest for anyone to cut out some sheet like I did above and play with their machine's settings, try 16, 14ga, up to 1/8" heat settings and see what it does for your weld dots. Control weld size with duration. Find the sweet spot for you machine and use it.

Robert, you are very correct with what you are saying , all machines have a sweet spot !

Thanks Sid

[MP&C]

....I wonder about it why a TIG weld with ER70S-6 rod would be any different than a MIG weld with the same wire. Have you done the cutter test with a TIG welded sheet? I'd sure like to see some hardness testing done to prove or disprove that claim. I'm sure a TIG fusion weld would be different than one made with the rod.

I haven't done the cutter test with Tig, but most of the guys on the metal shaping sites, especially the coachbuilders, state that O/A and Tig present softer welds than Mig. Most of the theories out there are above my head, so here's a good discussion on it. See what you make of it..

http://www.allmetalshaping.com/showthread.php?t=1287

[carls 56 (RIP 11/24/2021)]

thanks for sharing Robert.

[metalman57]

Welding gas can make the difference on how the puddle flows. When you compare TIG to MIG be sure you use the same gas / wire.

[567chevys]

Welding gas can make the difference on how the puddle flows. When you compare TIG to MIG be sure you use the same gas / wire.

Metal Man ,
Tell me how to used same gas for both types of welding , Tig uses Argon , and with a few exotic metals you use Argon-Helium . Mig uses 98/2 , 75/25 and last 100% CO2.

Sid