What's the max thickness of mild steel that can (should!) be welded with a 105 mig?

About 3mm flat out.

The stats on the SIP Trade Weldmate T105P - Gas

Says 4.5mm mild steel.

If you grind a v shape into the join you can increase the depth you can safely weld to, maybe make more than one pass is necessary.

John

Ta!

instead of doing multiple passes, do the christmas tree technique.

Basically you're doing triangles, (this might not explain well).

start at the left of the vee and fire up the welder, pool some weld, now move to the right side, pool some weld, move forwards and to the middle to make your triangle, pool some weld.

Now, move down half the distance you've just moved forwards and out to the left side. Pool some weld, move to the right side, pool some weld, move forwards and to the middle, pool some weld.

Hopefully you can see you're doing overlapping triangles. This technique should be used for welding verticals but it works like this as well. It puts a lot of heat into the piece as you never turn the welder off, its continuously on (which may be a bad thing if you're worried about heat affected zone).

If you leave a 1mm gap between bits to be joined you'll also find you get good penetration both sides as the weld will creep through.

ps when i say pool the weld i mean hold the weld at that point for a second, not start welding, wait, move the nozel start welding wait.

www.mig-welding.co.uk

quote:

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Originally posted by thunderace
www.mig-welding.co.uk

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You can weld super thick metal with a poxy little welder but it'll take shed loads of passes and the duty cycle of weaker welders isn't that great so you'll need to give it a breather every couple of minutes!!! (that's assuming you can notch it anyway)...

make sure you TEST your welds, there is the potential that it will look great but have very poor peneration - practise lots, destroy lots and then decide whether to trust your life to some structural welds.