How to Weld Plastic Sheets

Plastic sheets can be welded to form everything from vases to ductwork and everything in between. Welding plastic sheets requires a hot air gun and a plastic filler rod with the same chemical makeup as the plastic sheet to be joined. The hot air gun has a heat dial that sets the temperature of the hot air used to melt the plastic sheet. On the end of the hot air gun is a metal tip. The tip directs the hot air to the plastic sheet and can have a filler rod guide that allows you to feed the plastic rod into the plastic sheet joint.

A plastic sheet joint is where two sheets intersect. Both sheets need to have a 30-degree bevel. The bevel allows proper adhesion of the plastic filler rod. The bevel should go down two-thirds of the plastic sheet's thickness. For example, a 3/16-inch sheet should have a bevel 1/8 inch deep.

Making a plastic storage box with plastic sheeting is a great way to learn how to weld plastic sheets. The seams of the box offer practice welding plastic sheet joints in orientations other then flat.

Things You'll Need

• 3/16-inch white PVC plastic sheet
• 3/16-inch diameter white PVC rod
• Tape measure
• Permanent marker
• Table saw
• 12-inch combination square
• File
• Hand-held hot air plastic welding gun
• 3/16-inch welding tip
• Wire cutters

Instructions

1. Measure in 12 inches from one end of the white PVC plastic sheet with the tape measure and place a mark with the permanent marker. Set the guide on the table saw to cut on the 12-inch mark. Plug in and turn on the hot air gun. The gun's instruction booklet will have a table that has the sheet type (PVC) and the dial setting required to join the plastic sheets. Turn the dial to the correct setting. Let the hot air gun warm up.

2. Cut the PVC plastic sheet on the table saw. Turn the piece of plastic and make another 12-inch cut. Repeat the cutting process until you have five pieces of plastic sheet that are 12 inches by 12 inches. Set the table saw guide to cut 4 inches.x

3. Cut two pieces of PVC plastic sheeting that measure 4 by 12 inches. You will use these pieces to test the temperature of the hot air gun.

4. Remove the burrs from the five 12-inch square pieces and bevel one 12-inch side of each 4x12-inch piece with the file.

5. Line up the two 4x12-inch pieces of plastic sheeting lying flat on the table, with the beveled ends facing skyward and touching each other. Place the hot air gun at one corner of one of the plastic sheets, away from the joint. Hold the hot air gun 1/2 inch away from the sheet. While holding the gun, look to see if the surface of the plastic is starting to liquefy. If the surface melts, place a piece of plastic filler rod into the tip.

6. Aim the hot air gun at the center of the plastic sheet joint, 1/2 inch away from the deepest part of the bevel. When the plastic in the join starts to melt, feed the filler rod into the joint as you pull the hot air gun down the seam to reinforce the welded joint. Stop the weld after you have welded the plastic sheet joint approximately 3 inches. Release the filler rod and pull the hot air gun away from the joint.

7. Grab the filler rod 1 inch away from the weld joint. Pull the filler rod to ensure adhesion. On a proper plastic sheet weld, the filler rod will not tear away from the plastic sheet. Examine the weld around the plastic filler rod. There should be a slight bead of melted plastic on both sides of the plastic filler rod. If there is burn marks anywhere on the welded joint, turn the heat of the hot air gun down 20 degrees.

8. Lay one of the 12-inch square pieces flat on a table. Lay the other four 12-inch square pieces flat on the table. Slide each 12-inch square tight against each side of the 12-inch square piece lying on the table. Run the flat front edge of the hot air gun tip along the plastic sheet joints, pressing down firmly to tack the sheets together.

9. Gently stand two of the 12-inch square pieces upright. Align the pieces so that the vertical edges touch. Run the tacking edge of the tip down the seam to hold them in place. Stand another 12-inch square piece upright. Align the seam and tack them together. Perform the same process on the last 12-inch piece.

10. Weld the plastic sheets together using the plastic filler rod. As you feed the plastic filler rod and pull the gun, watch the front edge of the rod. You will notice a small bead of plastic in front of the rod. The bead is a sign that proper adhesion is taking place. Weld around all seams on your 12-inch square box.

11. Allow the seams to properly cool. After the box is cool, it will be watertight.

References

• Plastic Sheets and Supplies
• Work Experience

Resources

• Plastic Sheets and Supplies
• Plastic Welding Tips
• Hand-held Hot Air Guns