how hot is too hot when welding TPO roofing?

Yeah, wind can definitely mess things up, but heat matters quite a bit too. With TPO, I've noticed around 90-95°F ambient temp things start getting tricky - you gotta adjust your welder settings carefully or you'll end up scorching the membrane. It's not just about the air temp either; direct sunlight can push surface temps way higher than you'd think. I usually check surface temp with an infrared thermometer before starting, just to be safe.

Also, if you're welding in hotter conditions, you might want to speed up your passes slightly or dial down the heat setting a notch. Too much heat and you'll see discoloration or even bubbling, which weakens the weld. If you're unsure, try a few test welds on scrap material first - saved me from headaches more than once.

I've definitely noticed heat being tricky too. Last summer I tried patching a small section on my roof around noon - big mistake. The membrane got super soft and I ended up with bubbles everywhere...lesson learned, early mornings from now on.

"The membrane got super soft and I ended up with bubbles everywhere...lesson learned, early mornings from now on."

Yeah, that midday heat can really mess things up. I've been holding off on a similar repair because I'm worried about exactly this issue. Did you notice if the bubbling went down once things cooled off, or did you have to redo the whole patch? Just trying to gauge how forgiving TPO is with these kinds of mistakes...

Yeah, that midday heat can really mess things up.

I've had a similar experience - ended up with bubbles all over the place after welding in direct sun. From what I saw, the bubbles shrank a bit once things cooled down, but they never fully disappeared. I ended up redoing the worst sections just to be safe. TPO seems forgiving to a point, but once you cross that line into "super soft," you're probably looking at a redo. Early mornings or cloudy days are definitely your friend here...

I've noticed that too - once TPO hits that gummy stage, you're pretty much toast. Had a buddy who swore he could weld at noon in July, ended up with a roof looking like bubble wrap. 😂 Curious though, does anyone know if adjusting the welder temp down a notch helps at all when it's blazing hot out? Seems logical, but maybe it's just wishful thinking on my part...