Urethane bumper covers are often discarded
because of broken tabs and bolt holes. These bumpers can easily be repaired
using an airless plastic welder. Because thermoset urethane bumper covers do
not melt, you do not get a true fusion weld. Instead, the repair is similar to a brazing process. Grind the area to be repaired to expose clean
plastic and taper the plastic to a point. Expose sufficient area of plastic for the rod to bind. Grind the opposite side also, making sure to
expose an area sufficient for the rod to bond to, and grinding the plastic to a point. Apply aluminum body tape to the location
where you’ll be creating the new tab. The aluminum tape is stiff and
can handle the heat of the welding. After the tape is in place, melt the polyurethane
rod onto the tape, making sure to melt the rod onto
the existing plastic as well. Continue melting rod onto the tape
until you connect the tab and the thickness matches
the original thickness of the tab. Allow time for the rod to cool before
peeling the tape from the opposite side. Just as you did on the other side, melt rod
onto the existing plastic across the tab and the existing plastic at the other end of the tab. Smooth the tab and feather the rod onto the
plastic while the melted rod is still hot. Use a rotary tool to remove excess
plastic and to shape the tab. Be sure to remove excess plastic
from the opposite side as well. Finish shaping the tab with an abrasive disc. Here, we are using a right angle drill at a low-speed. Avoid using high-speed grinders
to prevent melting the plastic. Even though this is not a true fusion weld, you can
see here that you can create a very strong tab on urethane bumper cover using
the airless plastic welder.