How do you weld plastic?

To weld plastic, clean it with rubbing alcohol, drill holes at the ends of the crack, and warm the edges with a hair dryer. Melt plastic scraps with a torch lighter, and fill the crack with the melted plastic. Warm the repair with a blow dryer, and smooth with a spoon.

1. Clean the area to be welded

   Pour a small amount of rubbing alcohol on a paper towel, and rub the edges of the crack to clean them.

2. Drill holes at the ends of the crack

   Drill a small hole at each end of the crack to prevent it from spreading.

3. Warm the plastic

   Move a blow dryer set on the highest heat setting over the plastic around the crack. Be careful not to burn or melt the plastic.

4. Melt plastic scraps

   Hold a torch lighter close to a HDPE plastic scrap. Do not let the flame touch the plastic. Wave the flame back and forth to evenly heat the piece.

5. Fill the crack

   As the plastic becomes translucent, drip it into the crack. Work the plastic into the crack with a screwdriver.

6. Add a second layer

   To ensure a tight seal, melt a second piece of plastic and add a second layer over the first, pressing it over the edges of the crack with a screwdriver.

7. Smooth the weld

   Go over the welded area with a blow dryer. Smooth rough areas with the back of a metal spoon. Trim any excess plastic off with a razor blade.