I just about have my benchwork built. I am going to use homosote on top of the benchwork. Should I use 1/4" plywood underneath the homosote? I will be using Tortoise motors mounted underneath for my turnouts.
Thanks
Beetle
You should use at least 1/2" plywood and better yet 3/4". I built my layout with 1/2" plywood and homesote and i very happy with the results. However all the old timers who hang around the LHS tried to talk me into 3/4".
Split the difference. I used 1/2" on my original effort and am now getting ready to put on an add on section and I’m planning on going w/ 5/8".
The plywood is a good idea if you are installing the homosote flat. Thickness should be a function of span. 3/4 inch is gross overkill unless you intend to plop otherwise unsupported plywood atop a couple of leg sets (like the cheap folding banquet tables, which are 3/4 inch particle board.) 1/2 inch can span 24", while 3/8 would be adequate for the frequently-recommended 16 inch joist spacing.
Of course, if you are operating 1:12 live steam, you might need 3/4 inch ply - and something on top of it that is rated fireproof.
It is sometimes easy to forget that our benchwork needs to support picnic table loads, not a full scale house party.
Chuck.
Good quality 1/4" plywood is adaquate. 1/2" is ideal. 3/4" is overkill. The last layout I built, I used 1/4" plywood and 1/2" homasote, I never had any problems with sagging.
Nick
Thanks for the replies. I think I will go with 1/2". I hope to start cutting plywood next week.
Thanks again
It depends on the span between risers or cross members. The longer the span the more sagging you will get over time.
Agreed. For the loads we’re talking about, including its own propensity to sag, 1/2" ply supported with spans shorter than 20" will be bulletproof…well, you know what I mean.
1/4" plywood is OK…if you cut it into 3/4" strips and make spline roadbed of it. Also support it every 16" minimum. Also are you using 1/2" homasote or the premade roadbed stuff? The premade stuff is sorta thin and will need at least 1/2" ply under. Also depends on how well its supported. One could also glue it to 2" pink foam and do OK. However the foam needs good support too.
In my last layout, I used 1/2" Homosote glued, with yellow carpenter’s glue, to 1/2" plywood. This was supported on risers no more than 16" apart. I had no problems with this arrangement as far as sagging or stability. It sounds like you have pretty much made up your mind to use Homosote. While it does have the advantage of holding track nails well, I can tell you from my experience building my last layout that it is a mess to work with. When you cut it with any kind of saw blade, e.g., sabersaw, it creates a tremendous amount of dust. Be prepared to do your cutting outside or be prepared to do major house cleaning when you’re done cutting inside. Some will tell you that you can eliminate the dust during cutting by using a knife blade in place of a saw blade in your sabersaw. I tried this and found it is slow cutting in the extreme.
I’m about to start a new layout and I plan to use 2" extruded foam insulation board glued on top of 1/4" plywood. This technique has been described extensively elsewhere in this forum. Most people are using latex-based caulk to glue the insulation board to the plywood and to glue the track directly to the surface of the insulation board or to cork roadbed where a ballast shoulder is desired. I’m convinced that this is the easier and cleaner way to go. Check out the references to the use of foam insulation board for bench tops in this forum.
Bob