how hot is too hot when welding TPO roofing?

Great points, especially about testing scraps first - can't stress that enough. I've also noticed humidity plays a sneaky role. On muggy days, the membrane seems to soften quicker, even at lower temps. Had a job last summer where the morning was perfect, but by afternoon, humidity shot up and welds started looking glossy and overheated. Had to dial back even more than usual. Definitely something to keep an eye on...

Yeah, humidity's a sneaky one for sure. Had a similar issue last year - morning welds were spot-on, but after lunch it got muggy and everything turned gummy fast. Ended up dropping temp way below normal just to keep things clean... live and learn, I guess.

Humidity really does mess things up quick. Had a similar headache with some DIY flashing repairs last summer - thought I was losing my mind until I figured out the weather was the culprit. Glad it's not just me...

"Humidity really does mess things up quick."

True, humidity can complicate things, but honestly, temperature control is usually the bigger factor when welding TPO. I've found that even moderate humidity isn't as problematic if you dial in your heat settings correctly and keep the weld area clean. Last summer, we had a project where the crew blamed humidity at first, but after adjusting the welder temp down slightly and slowing their pace, the seams bonded perfectly - even on muggy days.

- Yep, humidity can be a pain... but honestly, it's usually the heat settings that bite you first.
- Had a crew once swear up and down it was the humidity messing up their welds - turned out they were just running way too hot.
- Dialed it back a notch, slowed down a bit, and boom, seams were golden even in swampy weather.
- So yeah, humidity sucks, but don't let it psych you out. You've got this.