I am making one of those panels next to a fridge, the dimensions will be 1.5 thick x 30 wide 92 tall. I recently made an identical one with 1/2 ply on both sides & it was lacquered a solid color & looks good. I just found the weight of it heavier than I like to deal with so I am wondering about using 1/4" with an MDF core on both sides & putting the ribs on 12 or even 8" centers. My question is do I have to worry about it being wavy at all. Rift sawn oak running horizontally clear coat.
maybe a full slab if the math works out, or even strips of foam if it doesn't. Thicker foam strips may just help prevent waviness. Foam will be just about as messy as mdf to work with.
Mike, years ago I made a 1-1/2" x 4' x 8' torsion box as an assembly table. The "skin" was 1/4" mdf as I wanted the surface to be flat. While I can't be sure, the ribs probably were 12-18 inches or so apart. I used 1 x 2's for the ribs purchased from a local borg. I glued and screwed (countersinked) the mdf to the ribs. It turned out dead flat with no wave at all. Keep in mind those inexpensive doors sold at the local borg are nothing more than a 1/8-inch skin (maybe 1/16-inch) with cardboard ribs and they sure are sturdy and do make a great assembly table. So, I think you should be fine with your 1/4-inch skin. Given your intended use, screwing the plywood would not look good. So clamping the skin to the ribs with, say, cauls during glue-up would avoid damaging the surface of the skin. Hope this helps. Jim
Hollow core doors are available in the size you require. Not knowing the application, one may be easily veneered or finished to your specification! They do stay flat and true and are quite inexpensive. What you are asking may be a lot of work and expensive to reinvent the wheel.
I have built a number of kitchens over the years and when this application happens I would use 3/4" plywood with a appropriate width stile on the leading edge. I was able to attach a cleat to the floor and the the upper cabinet was the upper attachment point.
I've done plenty like you describe as well, but he said, Rift sawn oak running horizontally clear coat.
Since I doubt he can buy RS oak with the grain running the short way across the sheet, I'm guessing he'll be veneering the final substrate, so I'd rather talk about how he intends to glue that. If contact cement, this is a big mistake. If he intends to use a vacuum bag with 1/4" mdf sides, on 18 or even 12" centers, even a shop vac will probably bend in between the ribs, so I'd advise you to get a helper if the weight is an issue, because your making the job harder than it needs to be.
If you need the horizontal grain on the front edge as well as the end, I'd veneer a larger sheet, maybe 3' wide, then cut a mitered corner so the veneer waterfalls around the corner for the front edge. That front edge along with the cleat on the back wall, floor and top is enough to keep it flat over time, and once the fridge is in place, nobody knows what the backside looks like.