How To Seal Your Classic Truck’s Wood Bed for Long-Lasting Results
- Louis Jasso
- May 28
- 3 min read
by Louis Jasso
I’m Louis Jasso, a third-generation wood coating specialist and the founder of Kustom Grain. I’ve spent my entire life around coatings, paint booths, and custom trucks. Today, I run a specialty coatings supply company, Fine Finish Supply, that works with builders, shops, and DIYers all over the country. One of the most common questions I get from truck owners is: “What’s the right way to seal my wood truck bed?”
Let’s clear up the confusion. Traditional finishes like spar varnish might’ve been the go-to in the past, but they’re brittle, yellow fast, and make future repairs a nightmare. If you want a finish that holds up under the sun, resists moisture, and actually looks like it belongs in a show truck, keep reading.
Before you start brushing or spraying anything, make sure you follow these steps to save yourself time, money, and heartache down the line.
Tip #1 – Start With the Right Product (Not the Cheap Stuff)
You don’t build a classic truck with discount parts — so don’t finish your wood bed with a bargain-bin clear coat.
KustomKlear by Kustom Grain is the product I recommend to everyone — professionals, hobbyists, and show builders alike. It’s a non-yellowing, water-based industrial clear coat designed specifically for outdoor wood. Unlike oil-based spar varnishes, it stays clear, moves with the wood, and breaks down from the top layer — meaning you can refinish it without sanding back to bare wood.
Most of the “truck bed disasters” I’ve seen come from using cheap spar varnish that flakes, yellows, or traps moisture. Don’t let your finish ruin your project. Invest in the right coating from the start.
Tip #2 - Sand, Sand, and Sand Again!
Surface prep is where great finishes start!
Start by sanding your wood with the proper grit sequence. for example, if the raw wood still has defects from the factory, like sanding swirls, planner marks etc. you will want to start with an 80 grit sandpaper and work your way through the grits till you hit 180 or 220. i like to follow the grit sequence 80, 180, 220. this will ensure a properly prepared surface. this is especially important if you will be applying a stain before your clear top coat. Make sure not to leave any sharp edges as that can and will cause premature failure of the finish. Blow off dust with compressed air or vacuum, and ensure the surface is clean from sanding dust.
Pro tip: Pre-seal all of your end grain first with KustomKlear. It’s a simple step that can add years of life to your finish. End grain tends to absorb the finish and will likely require multiple coats.
Tip #3 – Apply Like a Pro (Even If You’re Not One)
You don’t need a spray booth to get a professional finish — but you do need to follow the rules.
Apply your first coat of KustomKlear using a spray gun (best results), mini roller (for cabinet paints/clear). Apply the product with a medium coat and let it dry for 2 hours, then sand lightly with 320-400 grit or a fine scuff pad.
Repeat the process for 2–3 more coats. More coats = more depth, more durability, and more protection.
** Make sure you seal the all sides of every board. Moisture doesn’t care if it’s hidden.
Tip #4 – Keep Your Finish Easy to Maintain
One of the biggest advantages of KustomKlear is that it wears naturally from the top down. That means you shouldn't have to remove the old finish when it starts to dull — just clean, scuff, and apply another coat.
Unlike spar varnishes that delaminate and turn orange, KustomKlear stays crystal clear and stays stuck.
If you ever see a worn spot, just touch it up. That’s it.
Tip #5 – Let It Cure and Then Show It Off
Your final coat should cure for 24-48 hours before hard use or reassembly. Let it sit. Let it harden.
Then bolt that bed back in, hit your local show, and watch people stop and ask how your wood looks so damn good.
Because the truth is — your finish matters. And if you followed these steps, you just joined the handful of builders who do it right.
Whether you are building a show truck, or cruising the daily, the right finish turns your bed wood from “just okay” into something that steals the show. And with KustomKlear, that level of quality is finally within reach — for pros and DIYers alike.
👉 Ready to protect your wood truck bed the right way?Shop KustomKlear now at KustomGrain.comHave questions? Drop a comment below — or shoot us a message. We’re here to help.