by veefre Sat Jan 16, 2010 4:22 pmPolyethylene is a very slippery kind of plastic, and not much will stick to it.
The windshield washer fluid tank on my '67 is black polyethylene (I think). It sprang a leak where the sharp edge of the holding bracket hits it off location. It hits off location because the wiring harness has pulled away from the "firewall" just above the tank, and interferes with the fit.
I tried epoxy glue - it soon cracked when I installed the tank and started leaking.
I tried 3M Marine polyurethane sealant. It wouldn't stick to the poly.
Finally found something called "Poly-Weld" at Tap Plastics. It's an epoxy specifically for polyethylene. The only catch is that one must use a flame spreader on a propane torch and briefly sweep the (roughened) area to be bonded with just the lower temp faint yellow tip of the flame. After that, apparently, the surface is slightly altered and becomes charged and receptive to glue.
Anyway, this Poly-Weld seems to have done the trick. I also filed down the sharp edges on the bracket, as well as shimmed (with rubber faucet washers) the bracket out from the "firewall" a bit to make it easer to mate with the tank. Also clipped a zip tie that a previous Cobra alarm installer had cinched way too tightly to the washer fluid hose, the wiring harness, and God knows what else. Now the tank is much more easily installed and the Poly-Weld seems to be holding back the flood.
So far, so good.
The windshield washer fluid tank on my '67 is black polyethylene (I think). It sprang a leak where the sharp edge of the holding bracket hits it off location. It hits off location because the wiring harness has pulled away from the "firewall" just above the tank, and interferes with the fit.
I tried epoxy glue - it soon cracked when I installed the tank and started leaking.
I tried 3M Marine polyurethane sealant. It wouldn't stick to the poly.
Finally found something called "Poly-Weld" at Tap Plastics. It's an epoxy specifically for polyethylene. The only catch is that one must use a flame spreader on a propane torch and briefly sweep the (roughened) area to be bonded with just the lower temp faint yellow tip of the flame. After that, apparently, the surface is slightly altered and becomes charged and receptive to glue.
Anyway, this Poly-Weld seems to have done the trick. I also filed down the sharp edges on the bracket, as well as shimmed (with rubber faucet washers) the bracket out from the "firewall" a bit to make it easer to mate with the tank. Also clipped a zip tie that a previous Cobra alarm installer had cinched way too tightly to the washer fluid hose, the wiring harness, and God knows what else. Now the tank is much more easily installed and the Poly-Weld seems to be holding back the flood.
So far, so good.
