I totally get the frustration with trying to weld TPO in the heat. Last summer, I was patching a section on my garage roof—midday, direct sun, and the surface temp was way higher than I expected. Even with the welder set low, the membrane got tacky fast and I had to redo a seam that just wouldn’t bond right. I tried misting too, but it just made things messier. For me, early mornings worked best, but yeah... not always possible when you’re juggling work and weather. Sometimes you just have to pick your battles with the sun.
Honestly, I’ve had better luck just waiting for a bit of cloud cover or even working in the evening. Early mornings are nice, but sometimes the dew makes it tricky too. I actually found a cheap IR thermometer on Amazon—made a big difference knowing when the surface was just too hot to mess with. Sometimes it’s not even about the air temp, but those white TPO sheets soak up way more heat than you’d think. I wouldn’t bother with misting either… just seems to make things sloppy and doesn’t really cool it off enough.
I get what you’re saying about misting, but I’ve actually had a bit of luck with it—at least in short bursts. My roof faces south and by midday, those TPO sheets are like frying pans. I’ll sometimes do a quick mist just to knock the edge off before I start welding, but I keep it light so it doesn’t get sloppy. It’s not a perfect fix, but it buys me a few minutes when clouds aren’t cooperating.
The IR thermometer is a game changer though, no argument there. I used to just touch the surface and hope for the best... not smart. Now I try to keep the surface under 120°F if I can, but that’s not always realistic in July around here (central Texas). Early mornings are hit or miss for me too—the dew can be a pain, especially if you’re in a hurry.
I guess it comes down to what you’re comfortable with. For me, a little misting helps, but only if I’m careful. Curious if anyone else has found a better workaround for those brutal summer days?
Yeah, I hear you on the misting—sometimes it’s the only way to get the temp down enough to even start. I’m always a little wary, though, since I’ve seen guys overdo it and end up with seams that don’t hold up. That IR thermometer is a lifesaver, no doubt. I’ve tried throwing a tarp over the area for a bit to get some shade, but honestly, in Texas sun, it barely makes a dent. Early mornings are hit or miss for me too—dew just slows everything down. At the end of the day, I’d rather wait than risk a bad weld, but sometimes you just gotta work with what you’ve got.
That Texas sun is no joke—feels like you could fry an egg on the TPO some days. I’ve had to call it quits by noon more than once because the membrane was just too hot to handle, even with misting and shade. IR thermometer’s a must, but I still trust my gut if the welds start looking sketchy. I’ve seen seams fail after a summer or two when folks rushed it in the heat. Sometimes waiting for a cloud or just packing it in early is the only way to avoid redoing the whole thing later.
