Glad you mentioned the wind factor—I had a similar experience a while back. Was overseeing a roofing project on one of our buildings, and the crew was struggling big-time with their welds. At first, I thought they were just having an off day or something, but turns out it was the breeze coming off the lake nearby. Even though it wasn't strong enough to feel like a real "wind," it was enough to mess up the weld temps. Felt kinda silly afterward for not catching it sooner.
About the sunlight thing, I've noticed the same. One time we had two identical roofs being done at the same time—one shaded by trees, the other fully exposed. The shaded roof went smooth as butter, but the sunny one... let's just say it took a lot more patience and adjustments. Definitely seems like direct sun can push things into overheating territory pretty quick.
Anyway, you're definitely not alone in this. Seems like welding TPO is part science, part art, and part weather forecasting, haha.
Had a similar issue once inspecting a roof job on a super sunny day. The crew was getting frustrated because their welds kept looking sloppy, and they couldn't figure out why. Turns out the membrane was heating up way faster than they expected—like frying-an-egg hot. They had to dial back the heat gun settings quite a bit. Definitely agree it's a balancing act...and sometimes Mother Nature just likes to keep us humble, haha.
Yeah, been there myself—hot membranes can definitely throw things off. But honestly, dialing back the heat gun isn't always my first choice. Sometimes you actually need to move quicker across the seam or adjust your roller pressure instead. Lowering heat too much risks weak welds, especially long-term. It's counterintuitive, but I've found slightly speeding up movement, keeping the temp steady, and fine-tuning technique usually does the trick better. Just my two cents though...
"Lowering heat too much risks weak welds, especially long-term."
Good point, but I'd add a couple things from experience:
- If you're seeing smoke or discoloration, you're definitely pushing it. TPO shouldn't brown or scorch—if it does, back off a bit.
- Agree that speeding up can help, but sometimes it's just masking the issue. Technique matters, sure, but there's a limit to how fast you can move without sacrificing weld quality.
- Personally, I prefer tweaking the angle of the nozzle slightly or adjusting airflow before messing with temperature settings too much. Small adjustments there can make a surprising difference.
- Bottom line: if your seams are glossy and smooth without bubbles or scorching, you're probably in the sweet spot. If they're dull or rough-looking...time to rethink your approach.
Just my experience though—every job's a bit different.
Good tips overall, but I'm wondering—are glossy seams always the best indicator? I've had a few jobs where the seams looked perfect at first glance, shiny and smooth, but after a couple seasons they started lifting slightly. Made me question if glossiness alone is reliable long-term.
Also curious about airflow adjustments...do you find tweaking airflow makes a noticeable difference consistently, or is it more of a trial-and-error thing depending on conditions? I've messed around with nozzle angles plenty, but airflow always seemed like one of those "set it and forget it" things to me. Maybe I'm missing something there.
Totally agree on discoloration though—if you're seeing smoke or browning, you're definitely cooking it too hot. Learned that lesson the hard way early on...nothing like having to redo seams to teach you patience, haha.
