One of my desk tops is actually a solid core door. It spans across two filing cabinets, making for a nice, long work surface. The top has an attractive birch veneer skin which I never bothered to seal. I figured I would get around to it some day, and that day finally arrived. In addition, because the door is just 1-3/8″ thick, I was afraid it might sag in the middle. Given that I had to clear everything off my desk anyway, I decided to add some reinforcement underneath.
Choosing A Finish
My friend Nick Probst, a cabinetmaker in Oakland, CA, recommended an oil-urethane product called Arm-R-Seal. Made by General Finishes, it has an excellent reputation for yielding a beautiful, long-lasting topcoat.
I started by sanding all surfaces with 120 grit sandpaper, followed by another sanding with 220 paper. Since it was a fairly large surface, I used an orbital sander. After carefully wiping off all the dust, I rubbed on the first coat of Arm-R-Seal. You can see in the photo below how it definitely darkens the wood, but it also brings out the grain quite nicely.
Rather than having to breathe fumes in my house, I put the door on two sawhorses in my yard. The first coat was completed in the late afternoon, and by early evening I covered it with a clean tarp. The birch veneer was porous enough that it readily absorbed the first coat. The next morning I rubbed that coat with 0000 steelwool, followed by a second rub-down with Arm-R-Seal, satin finish. Here is what the birch veneer looks like after four coats, each with a successive ‘rubs’ of steel wool.
Easy As Pie
I stopped after seven coats. I was thinking of maybe going for ten, but I really needed my desk back and was about to take a trip. It takes hardly any time at all; just a little elbow grease. After almost every coat I waited for perhaps two hours, and then covered it with a tarp. There were squirrels messing around in a tree above, and I really did not want anything dropping on the drying finish. An oscillating fan helped speed up the drying process. You will notice that after so many coats of Arm-R-Seal plus the steelwool treatments the surface is super smooth — almost slippery.
Adding An Aluminum Strongback
Even after several years of use, the door was still as straight as could be. Still, I opted to add a 48″ piece of aluminum angle iron to prevent any kind of distortion. I used a jigsaw to ease the sharp corners. It is important to install plenty of strong screws, and not the ones used for drywall, as they can break. Make them plenty long so they get a good bite. Most of these doors have particle board centers, which have far less integrity than solid wood. If you look carefully at the photo below, you will notice that the angle iron does not sit centered between the left and right edges. I installed it slightly further toward the left, which is the rear edge of the desk. This was done to prevent scraping my knees.
By the way, I moved the door indoors and applied the last coat just before leaving on a 5-day trip. I cracked a few windows, and when I returned the urethane odor was entirely gone. Have fun with your refinishing project, and feel free to ask any questions, as always!