How to Apply Spray on Polyurethane Lining

Adding a layer of polyurethane spray to the truck bed provides protection from heavy tools.

Pickup truck beds see a lot of heavy loads and can receive significant wear and tear from use. Lining a truck bed with polyurethane is one way to protect the truck bed liner and keep it looking like new. Polyurethane liners work by bonding mechanically to a surface. It grips onto tiny grooves and microscopic ridges when it is applied. Do it yourself polyurethane liners are available for purchase at many automotive specialty shops. It is generally safe to use, but still requires the person spraying it to protect his skin from direct contact and his lungs from inhalation.

Things You'll Need

• 36 grit sandpaper
• Automotive prepaint cleaner
• Plastic sheet
• Tape
• Half-face respirator with chemical cartridges
• Polyurethane lining primer
• Polyurethane lining kit
• Mixing paddle attachment
• Drill
• Spray gun

Instructions

1. Sand down the area you are going to spray with sandpaper, and scuff up the coating well, focusing on the deep grooves of the truck bed. Clean the area thoroughly to get rid of any sanding debris with a prepaint cleaner.

2. Cover the parts of the truck that you are not going to spray with plastic and tape it down to secure it in place.

3. Put on your half-face respirator. Spray a light coat of primer over the truck bed. Let it sit for 15 minutes until it is tacky to the touch.

4. Follow the instructions on the polyurethane packaging to combine the containers correctly to make the polyurethane mixture. Mix with a paddle and drill until the color has completely blended together. Pour a small portion of the mixture into the spray gun hopper.

5. Set the air pressure of the spray gun to 50 PSI. Set the pressure between 45 and 75 PSI. Hold the spray gun 18 inches above the spray area. Hold the spray gun at a right angle and move it with your arm not your wrist. Pull back as you paint until you create a spray pattern that you like. Experiment with a light coating first until you find the texture that you want your truck lining to have. Coat all areas of the liner evenly.

6. Remove the tape and plastic sheet. Peel the tape towards the sprayed area to create a sharp looking edge on the truck bed. Let the polyurethane lining cure for 24 hours before use.

7. Drain the hopper once you are finished spraying the polyurethane and dispose of the remaining mixture according to your state regulations. Let the mixture residue harden in the hopper and gun overnight. Remove the hopper from the spray gun. Take out the front cone and washer of the gun. Remove the air shaft from the rear of the gun. Take out all the hardened polyurethane from the hopper and gun and then reassemble it.

Tips & Warnings

• The spray guns needs to have at least 17 CFM at 90 PSI to handle the viscosity of the polyurethane mixture.

• Use polyurethane spray-on liner in a well-ventilated area. Always wear a respirator when spraying polyurethane to protect your lungs from being damaged by inhaling the chemical fumes.

References

• Tonno Covers: Al's Liner DIY Spray in Truck Bed Liner Instructions
• Speedliner: Bulletproof Bedliners
• Discount Truck Accessories: Do it Yourself Bed Liner Spray In