I've gotten myself a hollow core interior door slab for use as benchwork. I'm finally going to try my hand at something larger than the little circle of track I've been fiddling around with. Question........ my previous attempts used 1/2" plywood in the benchwork. I was surprised at the warping this suffered. In reading threads at this site, it seems that a number of folks are of the opinion that painting only one side of the plywood, while leaving the bottom unpainted could potentially have caused the warping. So........ should I paint both sides of the door this time to head this problem off? Or is warping less of an issue just by the design of the door?
I would paint or seal all exposed wood surfaces. I found that this minimized any warpage of the wood. It also depends on the grade of wood used in the door. Stay cool and run steam.....
I 2nd what Bob said. My very first layout was a hollow core door and I did not paint or seal the wood. I went ahead with scenery and at first all was well. After I got back from college for a semester my layout looked like a roler coster:angry: Paint the door with a good latex in an earth tone, it will seal and help with scenery later.
Paint both sides! You can also paint the edges, but this is a good practice rather than an essential. As paint of most any sort dries, it contracts. This contraction can get very powerful over the expanses of a door. If you paint both sides, the forces of contraction usually even out. You should use the same type of paint, but not necessarily the same grade. For many years while I was building furniture, I had a slop grade of varnish or lacquer that I used on the back sides while I put the good stuff on the surface. The advent of sprayguns made this too much trouble for the slight advantage of cost. Before I quit a few years ago, I just sprayed all sides.
My advice: don't use any paint! My last layout was an all-door job - it started life in a very humid Virginia garage before migrating upstairs. No problems with warping at all in spite of not having been painted. A hollow core door consists of two thin panels (usually luan) separated by a honeycomb material that's good in compression. If you paint then each luan sheet is getting paint on one side only. Given that the honeycomb material is bonded to both sheets it may not be a problem if you paint but my experience is that it is unnecessary. Use a good support for the doors. Pairs of steel wall stud rivetted back to back to make longitudinal I beams is strong, light and stiff. Use screen door clips to secure the doors to the beams as it's hard to drill through the flange of the channel from underneath.
I'm on a door, and I painted both sides with dirt-colored paint. You can paint some cheap trim, mitre cut the corners, and nail it on the edges for a nice finish. If I were to build on another door, I'd do it exactly the same way again. In fact I might use a panel or two on the next big layout.
I have a 2" foam sheet glued to the top surface of my door, so no paint for me. Once the fascia and backdrop are on I may just forget that there's a door under there! I agree with Mark4Design, there should be no need on a properly constructed door.
