How to Weld Polypro Plastic

Polypropylene is widely used in the construction and automotive industries. When cracks or breaks develop in a component made from polypropylene, the defected area can generally be welded. Like other welding techniques, there is prep work involved to ensure that the weld has the proper amount of penetration, strength and integrity. Prepping the polypropylene involves cleaning the weld area to remove contamination and beveling the sides of the weld joint. Proper bevels need to be performed to an adequate depth to allow the weld to penetrate a minimum of one-half of the thickness of the polypropylene material.

Instructions

1

Plug in the handheld plastic welder and set the temperature to 575 degrees Fahrenheit. Slide the tacking tip onto the air outlet nozzle of the plastic welder. Allow the welder to heat up while you prepare the connection.

2

Bevel both sides of the weld joint with the knife. Place the knife against one side of the joint. Pull the knife toward you, with the knife blade angled away from the direction of travel and the blade of the knife at a 30 degree angle to the material. Use long steady strokes to keep an even bevel along the entire length of the weld. Continue the process until you have a bevel that is one-half of the material thickness deep. Perform the same bevel on the other side of the weld joint.

3

Remove contamination from the weld joint by lightly cleaning both sides of the weld joint with a piece of emery cloth. Wipe the area with a clean rag to remove loose particles surround the weld joint. Slide the two pieces of polypropylene together, butting the edges tight.

4

Hold the welder, with the tacking tip lying flat on both edges of the polypropylene. With slight pressure, drag the tacking tip along the joint in one continuous pass to secure the weld joint. Remove the tacking tip with the pliers and set the tip on an area that will not be damaged by the hot tip.

5

Attach the speed tip with the pliers to the air outlet of the plastic welder. Allow the tip to heat to temperature.

6

Insert a length of polypropylene filler rod into the speed tip. Place the plastic welder against the weld joint. When the polypropylene liquefies, feed the filler rod into the weld joint as you pull the plastic welder along the seam. Examine the weld joint as you pull the welder. A proper weld joint will have a small puddle of melted polypropylene in front of the filler rod and along both sides of the filler rod.

7

Cut off the end of the filler rod with the wire cutters after the weld joint has been completed. Make additional passes on thicker material to completely fill the beveled area of the weld joint. You do not need to perform any additional prep work between passes.

8

Allow the weld joint to cool thoroughly before you apply any strain to the welded area.