Yeah, hotter definitely isn't always better. When I did my shed roof last summer, I figured cranking the heat would speed things up—ended up with seams looking like melted cheese sandwiches. Took me a whole afternoon of trial and error to find that sweet spot. Honestly, sometimes I wonder if those recommended temp ranges are just rough guesses...
"Honestly, sometimes I wonder if those recommended temp ranges are just rough guesses..."
I get why you'd think that, especially after your melted cheese sandwich fiasco (been there myself!). But from what I've read and experienced, those recommended ranges aren't just guesses—they're usually tested pretty thoroughly by manufacturers. The tricky part is that ambient conditions, like humidity or wind, can really throw things off. Last fall, I welded some TPO on a breezy day and had to bump the heat slightly above the recommended range to get a clean seam. So yeah, guidelines are helpful, but you still gotta adapt to the situation.
The tricky part is that ambient conditions, like humidity or wind, can really throw things off. Last fall, I welded some TPO on a breezy day and had to bump the heat slightly above the recommended ...
Yeah, those temp ranges are solid starting points, but they're definitely not foolproof. Like you said, wind and humidity mess things up big time. Had a similar issue last summer—ended up dialing the heat back quite a bit because the TPO was practically turning into soup...
Yeah, ambient conditions can really throw a wrench in things. I've seen guys stick religiously to the manufacturer's recommended temps and still end up scratching their heads when the welds don't hold. It's definitely more art than science sometimes.
One thing I've noticed is that the color of the TPO can also make a surprising difference. Last summer, I was inspecting a job where they were welding white TPO on a blazing hot day, and they had to dial the heat way back because the material was already softening up just from sitting in the sun. On another job, same day, same conditions, but with gray TPO, they had to bump the heat up slightly because it wasn't absorbing as much heat from the sun. Weird, right?
Another factor I've seen overlooked is nozzle distance and speed. Even if your heat setting is spot-on, holding the nozzle too close or moving too slowly can turn your seam into melted goo pretty quickly. I usually suggest practicing on some scrap pieces first—just to get a feel for how the material reacts under current conditions. It takes a bit more time upfront, but it saves headaches later.
Have you guys noticed any difference in weld quality or ease depending on the thickness of the TPO? I've heard mixed opinions—some say thicker membranes are easier because they're more forgiving, others swear thinner membranes weld quicker and cleaner. Curious what your experiences have been...
I've only done one TPO roof myself (my own garage), but I used a thicker membrane and it seemed pretty forgiving. I practiced on some scraps first, like you suggested, and found it easier to control the heat without melting through. Can't speak for thinner stuff, but thicker TPO felt less finicky to me. Could just be beginner's luck though...
