DIY Truck Bed Liner Spraying Tips

If you have a truck bed that appears quite used or if objects tend to shift around on the smooth painted surface, then it may be in your best interest to add a bed liner to the truck. The most permanent of these liners are spray-on varieties, and you can add this type of liner to the truck bed yourself. Spray-on truck liners are made from liquid polyurethane materials, and you can add enough of the spray to form a layer that is anywhere from one-sixteenth of an inch and four inches thick. Most spray-on liners contain gritty materials to help provide grip to objects that sit in the truck bed. If you think this liner is right for your truck, then keep reading to learn about some tips to add the liner yourself.

Prepare the Bed Properly

Before you can add the spray-on liner to your truck bed, you will need to prepare the bed properly so the polyurethane material sticks. If it does not bond to the bed, then it can bubble up over time and come loose from the metal surface. This requires you to remove as much of the automotive paint and rust as you can so the liner can adhere to the steel underneath. While an electric hand sander with a piece of 120-grit sandpaper can remove the paint eventually, a hand grinder with a wire brush will remove the paint much more quickly. For this project, choose a cup brush with coarse carbon steel bristles. Cup brushes are shaped much like an upside-down cup with a hollow center.

Place your hand grinder on low speed and move the cup brush along the bed liner in a circular motion. Remove as much rust and paint as you can. If rust remains, then use a piece of 120-grit sandpaper to release the rest until no spots remain. Afterwards, use a scrub brush and dish soap to scrub the liner completely. Rinse all the rust and paint residue away with the help of a pressure washer. Set the washer so it releases 4,000 PSI of pressure if possible. This high pressure setting is able to strip paint, so it can release some of the leftover paint on the truck bed along with the paint chips and rust debris. When you are done, degrease the entire bed surface with the help of some trisodium phosphate. Follow the directions on the package to mix the powder with water and use a sponge to apply it to the truck bed. Use a hose to rinse the bed.

Buy the Right Sprayer and Apply Liner Correctly

Spray-on liners are meant to be sprayed onto the surface of the bed liner. This means that you will need to either rent or buy a sprayer device to add the polyurethane fluid. An automotive undercoating spray gun is the best choice to add the liner. These guns are meant to add smooth and even layers of rust protection materials or rubberized coatings to the bottom of vehicles. The sprayers come with a hand trigger nozzle and a small canister that sits underneath it. A hose attaches to the back side of the trigger handle and this hose attaches to your air compressor. This allows air to mix with fluid so a mist is released from the nozzle.

Make sure to purchase a relatively large air compressor with the sprayer so you will have a consistent supply of air during the spraying process so the gun does not stop in the middle of your spraying session. When you are ready, fill the small canister with the polyurethane liner solution. Some liner solutions will require you to mix two different compounds together. One compound is typically a hardening agent, so mix only what can fit into the canister so the liner fluid does not harden before you can spray it on the truck bed. Test the spray on a large piece of cardboard and then hold the gun about two feet from the bed liner. Pull the trigger on the gun and release the spray as you continuously move the nozzle.

For more information about truck beds and how to line them, contact a manufacturer through a website like