Unless I can find some Polyurethane rods this won't happen, I tried using some slivers of the scrap bumper, and it just won't melt properly, as soon as it dries it turns to powder and natually..won't stick
I'm using a $50 heat gun that I picked up at Home Depot a while back, plus a heat gun welding tip that I shimmed to make fit, it's capable of welding 1050 degrees, I'm setting it at about 350 tho, it takes forever to melt it at that heat, but any hotter starts to burn it