"Makes me wonder, is there a noticeable difference in weld strength or longevity when you're forced to slow things down and lower the welder temp?"
Had a similar issue when I did my garage roof last summer. My welder was acting up, so I dialed down the heat and went slower than usual. Honestly, haven't noticed any difference yet—no leaks or lifting edges, even after some heavy storms. Personally, I think consistency matters more than speed or temp alone...as long as you get a solid, uniform seal, you're probably good.
I've seen this a few times inspecting roofs, and honestly, lower heat isn't necessarily a bad thing—as long as you're patient. The key is making sure the weld is fully fused without gaps or bubbles. If you slow down too much, though, you risk overheating one spot and underheating another. Best bet is to test your welds periodically by gently probing the seam edges with a screwdriver or seam probe...if it holds firm without lifting, you're probably golden.
"Best bet is to test your welds periodically by gently probing the seam edges with a screwdriver or seam probe...if it holds firm without lifting, you're probably golden."
Good advice overall, but I'd add that relying solely on the "probe test" can sometimes give false confidence. I've seen seams pass the screwdriver test initially, only to fail after a few weather cycles. It's worth double-checking tricky spots after some temperature swings or rainstorms. Better safe than sorry—no one wants callbacks for leaks down the road...
Good advice overall, but I'd add that relying solely on the "probe test" can sometimes give false confidence.
Yeah, the screwdriver check is handy, but honestly I've found visual cues just as important. If the seam looks glossy or overly melted, it's likely overheated and brittle... learned that the hard way after a summer heat wave cracked mine open.
I get the point about visual cues, but honestly, even those can be misleading sometimes. I've seen seams that looked perfectly fine—no gloss, no obvious melting—but still ended up brittle after a few months. It's tricky because ambient temperature, wind, and even humidity can change how the material behaves at the same welding temperature.
Personally, I invested in a cheap infrared thermometer (nothing fancy, just a basic model from the hardware store), and it's made a noticeable difference. It helps me dial in the temperature more precisely, especially on hot summer days when surface temps can fluctuate wildly. The screwdriver test is still useful, but combining it with an actual temperature reading removes some guesswork.
Not saying visual checks aren't valuable—they definitely are—but relying on them alone feels like gambling with your roof's lifespan.