Hi,
I’m about to glue up my first 2’x8’ section of benchwork. I’ve got a 1"x4" fingerjoint pine box frame built up as a base, which is adequately flat. I plan to lay plywood on that and homosote on the plywood. I’m trying to decide on the thickness of the plywood. I was thinking 1/2" BC or AC exterior plywood and glue the homosote to the plywood with white wood glue. I’ll use coarse drywall screws to screw through the homosote and plywood into the frame. I’ll also use screws temporarily to clamp the homosote to the plywood in the open areas where there’s no frame.
Am I on the right track? What thickness of plywood is recommended? Any idea how much glue I will need?
Thanks,
Jim
Use latex caulking or one of the varieties of liquid nails as your adhesive and no screws are necessary – just put adequate weight on the top until the adhesive sets. I have used both, as well as industrial carpet adhesive, which comes in one gallon cans. I used the carpet adhesive on my latest HO scale layout and it seems to be sticking much better than caulking or liquid nails. CDX graded plywood would be sufficient for your benchwork.
1/2" over framing, 3/4" where unsupported by framing. That’s what I do. As far as homosote goes, if you can get it, by all means use it. My nearest supply of it is about 80 miles away, so naturally, I’m not using it. I just use beaded polyboard over the plywood. It makes a good sound deadener, especially if two layers are used. Well, that’s my 2 cents.
I use cleats underneath and screw everything from underneath sos when you cange it you can get at all the screws. The homasote I glue with Elmers carpenters glue.
I used 5/8" plywood as a base and then screwed and glued the homosote over the plywood using a few drywall screws and yellow carpenter glue applied liberally. Homasote makes a great base. You’ll really appreciate its qualities.
Heres a pic of my layout with the homasote applied over the plywood. As you can see, I also used spackling to cover the drywall screws I used in the homasote. I probably used a few dozen screws over a 11X2’ area.
In my last layout (N scale), I used Homasote glued to 1/2" fir underlayment plywood (5 Plys) with Elmer’s yellow Carpenter’s Glue. Since I was using the cookie-cutter method, there were places, especially along the main line, where I could clamp the Homasote to the plywood with various size “C” clamps to hold them together until the glue set. Be sure to use something between the clamp and the Homasote to prevent the clamp from denting the surface of the Homasote. A small block of 1X lumber works well for this. In yard areas where I couldn’t use clamps, I simply placed bricks at close intervals to weight the Homasote down until the glue set. It occurred to me that an alternative might be to run drywall screws through pieces of 1X lumber into the Homasote and plywood to spread the force over a larger area of the surface. After the glue sets, remove these holddowns and patch the screw holes with spackle. I’m not sure how using screws to hold the Homasote to the plywood permanently would work because the screws might have to be located and removed during later phases of construction.
An alternative is to screw into the Homasote from below. You’d want to use a clearance hole in the plywood, but the screws should hold quite well in the Homasote. That said, I’ve always glued my Homasote like RFinch.
my thoughts, your choices
Fred W
where it’s always 1900 in foggy coastal Oregon (but I can still smell the salmon sizzling on the grill)
For a 24" wide top, 1/2" plywood is fine as long as you have supports (1x4’s) underneith at proper spacing to avoid any sagging. If you really want to make sure it can take your weight climbing on top, you can use a double layer of 3/8" plywood to give you superior table top strength. This will give you a total thickness of 3/4" but with the advantage of more plys than a single sheet of 3/4". And, 3/8" is certainly MUCH easier to cut and to handle than a sheet of 3/4". Is it overkill? For a 24" wide table…sure it is,but you will have a table that you will not have to worry about ever.
