Fix broken plastic pieces with plastic welding

Here's how I fixed some license plate light covers using some quick and dirty plastic welding. These covers are from a 2001 Toyota Tacoma and had cracked around the screw holes.

Finished shot of plastic piece repaired

To see what we're aiming for, here are some before/after/original shots:

2001 Toyota Tacoma bumper license plate light covers

It's not pretty, but these pieces aren't visible - they just need to function properly.

To begin, I cut off a piece of scrap plastic from an old stereo mounting bracket.

Cut filler piece from old stereo mounting bracket.

I marked the filler piece to get a rough outline of the shape I needed.

Marking plastic filler piece

Then I cut off and sanded down the extra material.

Cut plastic filler piece Sand plastic filler piece

The filler piece doesn't have to be a perfect match - you just need it close enough that you can melt it into shape.

Showing fitment of plastic filler

After the scrap piece was shaped, I melting together the two pieces pushing down and forward with the wood burning tip. The melting plastic gives off nasty fumes, so a respirator during this step is a must. I use this 3M Comfort quick latch respirator with these 3m cartridges.

Melting together plastic.

If you have any gaps you can fill them by melting in some plastic shavings.

Filling gaps with plastic shavings

After finishing the front, I flipped it over and melted together the back. At this point I had completely covered over the screw hole, but I just re-drilled that later.

Melting back piece

Once the repair piece was fully molded into place, I sanded it down to shape. You can see here the replacement piece is super secure, even while being hit with the high-speed Dremel.

Here's some shots of the finish pieces all repaired and ready for re-assembly.

Fixing plastic this way isn't necessarily pretty, but it's stronger than glue and you don't have to wait for the repair to dry before working with it.

Supplies Used

3M Comfort quick latch respirator Very comfortable to wear, and lets you quickly open the front of the respirator when taking a break, without having to undo the straps around your head.

3M Paint respirator cartridges Works with above respirator

Wood burner