My uncle swore by using a 4-inch drywall knife for seam glue, and I finally saw why.
He told me for years that the wider blade spreads the adhesive thinner and more even than a trowel, especially on a big commercial job. I always used my standard 6-inch trowel and thought he was just set in his ways. Last month on a 2,000 square foot office install in Tacoma, I tried his way on one room as a test. The seam practically disappeared after stretching, and I saved a bunch on glue. Now I'm wondering if this is a common trick or if I just got lucky with that particular carpet backing. What's your go-to tool for seam adhesive?
That part about the seam practically disappearing is what sold me! I've had the same stubborn moment with my dad's old tricks. He used a paint roller to spread seam glue, and I laughed until I tried it on a tight-loop commercial grade. It laid down so thin and even, just like your uncle's knife trick. Sometimes the old ways just work.