![This is a failed test-splice on a PTFE (Teflon) single-ply expansion joint belt. If you use a heat-seal iron like the one in this photo you might want to replace it with a smaller, hotter iron. A 120V extension cord can only provide so much current, so concentrate it in one spot instead of spreading it out!](https://interepinc.com/wp-content/uploads/2016/07/14714391_1686942744956970_5432253715195101184_n.jpg)
This is a failed test-splice on a PTFE (Teflon) single-ply expansion joint belt. If you use a heat-seal iron like the one in this photo you might want to replace it with a smaller, hotter iron. A 120V extension cord can only provide so much current, so concentrate it in one spot instead of spreading it out!