I have the same topic going in the General Discussion forum. The three or so paragraphs below is one of the replies I received. After reading it I realized overkill is better than finding later that I cut myself short. My decision is to go with 3/4" Birch for strength and no worry of warping. The cost is more but as stated, you spend so much on the trains and everything else, why slack on what is supporting everything.
I used 3/4" plywood on my layout for three reasons:
1. Peace of mind. You're going to invest $100's, of not $1,000's in materials on the layout, not to mention years of work on it, and pinch pennies for $50 or so and HOPE you didn't cut yourself too thin? Unless you plan on moving your layout around town weekly, go for the most robust design you think you'd ever need, and then step it up further an additional notch, and sleep comfortably for the next 30 years.
2. Overkill in strength. I wanted to be able to climb on the layout and not have things move. If you have track on risers ANY vertical deflection of the base will kill you, as it'll be magnified 100 fold. I've found myself shimming the track with pieces of paper to get the final alignment perfect. If your layout is sagging even 0.10" you'll see it in the running of your trains.
3. Sound control. Heavy boards transmit les sound than thin and lightweight boards. If you want a quiet layout you generally need to build a solid layout.
That's my $0.02.
Mark in Utah
I think Mark's two cents makes sense!
Bill
Any of the commonly available sheet goods will be fine for the top of the benchwork, as long as it is securely anchored to the framing. You can use 1/8" luan and staple it down if you want, or you can use 1 1/8" T&G floor underlayment. Properly fastened, both will be equally flat. Properly fastened, of course, is the key. Either use pneumatic tools (nailguns/stapleguns) or predrilled screws. If you're using plywood ripped down as framing members, predrilling is even more important, otherwise you're likely to split the plys, as reported previously. Predrilling eliminates this problem. If screwing, do yourself two favors: first, use square drive screws. Second, do not use drywall screws. They are very brittle, a function of their hardness.
One consideration regarding the heavier plywoods is that they can, if warped, exert so much force on framing members they're attached to that they can win the tug of war and pull the framing member out of shape. While rare, this is not impossible. Thinner plywoods and MDF/particle board do not bear this risk, and using stout framing members also mitigates the risk.
Additionally, both sides should be equally "sealed". Paint (not latex) or a film finish (varnish, lacquer, or shellac) will seal quite nicely. White oil based paint is the best option, at least for the underside of the benchwork, and then another color of oil base for the top. This applies whether you choose plywood, MDF, particleboard, or any other wood based sheet good.
5x5 Baltic Birch is generally not available at any of the home improvement warehouses, aka "the Borg". It is available in 3mm (3), 6mm (5), 9mm (7), 12mm (9), 15mm (11) and 18mm (13) thickness, roughly corresponding to 1/4", 3/8", 1/2", 5/8" and 3/4" thick. The number of plys is in parantheses. Any lumberyard that supplies the cabinet trade will usually stock Baltic Birch, as it is the preferred sheetgood for drawers nowadays.
For the 1/2" top and 1x4 framing, what would you suggest for the maximum span between frames? Both along the grain of plywood and across?
The answer depends in part on what you plan on putting on the benchwork. If you're going with extensive plasterwork for the scenery and a roundhouse that's going then host a dozen O scale brass steam locomotives, consider 16" centers. Lightweight scenery can be done with 24" centers, easily. If, for peace of mind, you want to go with 16" centers, have at it. The only downside (other than some additional cost and work) to 16" centers is each frame member restricts placement of under bench infrastructure, i.e. switch machines and other such goodies.
Plywood, from a practical structural standpoint, has no grain. Each ply is laid up at a different angle from the previous ply, giving the resulting sheet equal strength in both directions. Visually, the grain usually runs the long length of the sheet, but structurally, it makes no difference for our purposes.
RFinch wrote: To Don Z:Thanks for the information on the plywood. Next time I'm at Lowes or HD I'll check to see if they stock 1/2" birch plywood with 7 plies. I know they stock 3/4" birch/maple plywood at the Lowes store. Are you putting anything on top of the 1/2" plywood like foam or Homasote?Bob
To Don Z:
Thanks for the information on the plywood. Next time I'm at Lowes or HD I'll check to see if they stock 1/2" birch plywood with 7 plies. I know they stock 3/4" birch/maple plywood at the Lowes store. Are you putting anything on top of the 1/2" plywood like foam or Homasote?
Bob
Bob,
I'm using both 1/2" and 2" pink foam on top of the plywood depending on the elevation needed. I use the 1/2" for under the track, and the 2" for scenery elevation. Since I can't get the 2" foam here in Texas, I bought 5 sheets last summer while in South Dakota and crammed them into our RV for the trip back to Texas.....the wife was oh so happy with me....
Don Z.
Research; it's not just for geeks.
I have a modest cookie cutter that I'm working on. I used 1/2" plywood (one side was a finished side, sanded) and 1x4 pine from HDepot. My center spacing varies from 12-16". I think that for 1/2" flat benchwork, 16-24" centers is fine, and for anything thinner you might keep it 16" centers. Depends how stout you want it.
I also experienced some warping with the 1x4. When moisture leaves the wood, it flexes where it wants to. Screw your perimeter framing in such a way that you can remove it later if it does warp. Place your screws close enough to the edge so that you don't roadbed over them. This saved me when I needed to remove a long 1x4 to rip it straight again when it warped a month after I installed it.
Good luck.
RFinch wrote: I'd be interested in knowing where jbloch was able to find 1/2" plywood with 5 plys. I think the 1/2" pine plywood stocked by my local Lowes and HD has only 4 ply.Bob
I'd be interested in knowing where jbloch was able to find 1/2" plywood with 5 plys. I think the 1/2" pine plywood stocked by my local Lowes and HD has only 4 ply.
I'll play devil's advocate here and tell you I can buy 1/2" Baltic Birch plywood with 9 plies, guaranteed to have no voids in the inner plies and sells for $22.00 per sheet. The only drawback is the sheets are 5'x5' square. The 1/2" Birch plywood I used from Home Depot has 7 plies and runs about $25.00 per 4x8 sheet. I prefer the birch because the face is smooth, has no plugs and is flat. It also eliminates any surface prep in order to use it on the layout.
Just my .
I think for model RR benchtop applications 3/4" plywood is probably overkill. On my last N scale layout, I used the cookie-cutter method with 1/2" fir underlayment plywood with 5 plys. 1/2" Homasote was glued to the top of the plywood. This two-layered structure was supported on 12" to 16" centers with 1x risers. I never noted any problem with sagging, etc. using this arrangement. When I checked with the lumber yard where I bought the 5-ply plywood 20 years ago they said they no longer stocked it and it either was no longer being made or it was very hard to find.
I would agree with all of the above. Given the quality issues with Lowe's/HD lumbar, I plan on purchasing my wood at a local lumber yard. As far as thickness of the plywood, has been discussed in several other threads: my take is that 1/2 inch thickness is adequate, but in 5 ply, don't use 3-ply. I plan on using 16 inch joist supports, though other threads have indicated you may be able to go as wide as 24 inches. If you're using L-girder construction with joists, you can just move/slide the joists easily if you need to(for swtch machines, etc.)--may be more of an issue with open-grid framework.
Jim
You might want to checkout luan plywood that is used as underlayment under vinyl flooring. I believe it comes in 1/8", 1/4" and 1/2" thicknesses. Luan plywood tends to have a lower moisture content than pine/fir plywood and therefore has less of a tendency to warp. It's not considered a high quality plywood like furniture-grade birch plywood, but its cost is significantly less. I don't know if Lowes or Home Depot stock the 1/2" thick material. Another trick to find relatively flat pieces of plywood is to pick your pieces several sheets down in the pile. It helps to have a helper to do this easily. Another possibility is to buy A/C or B/C pine/fir plywood and store it flat in your train room (not directly on a concrete basement floor) with some weights on top to straighten it out or keep it straight until you use it.
To Kimble:
I'm glad you have a good Lowes in your area. The one I have in our area has the usual junk lumber. In the 1x pine lumber area, they only carry #2 pine which looks like it's only good for kindling wood. Large knots, bent and twisted. Finally, I went to two Home Depots in the area and after picking thru their "clear" pine was able to find about 8 1" x 4" x 8' that looked reasonably straight at $6.95 each. I had the occasion to visit the lumber yard where I used to live and from which I bought most of my 1x lumber for my last layout 20 years ago. It was like a time warp, there in exactly the same location in their storage shed was beautiful 8', 10', 12' and 16' 1"x4" #2 pine with tiny knots and extremely straight. I may be making the 2 1/2 hour round trip with my truck to get a supply while it lasts.
I'm surprised at Lowes. I love the one in my town (Portland, Maine). I rarely have to pick too much though a pile to find good wood and the best part is, there is hardly anyone ever there! It's like I'm have my own store...
Across town at the Home Chepo , I could spend a half an hour picking though the pile and still not find decent lumber.
This weekend I'm picking up a couple sheets of 3/8" birch plywood. Smooth, flat and under $20 a sheet.
Rob Carignan
Portland, Maine
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
Thanks.
Hi- Went to the local Lowes to scout out materials for my new layout. I couldn't believe how badly warped all of the plywood was. The thicker/more expensive stuff (3/4") was better, but it's quite expensive. My layout is odd shaped, but would require about four 4x8 sheets.
I am planning to use 1x4 framing under the table, but I'm not sure if it's better to simply add more framing, use a thinner plywood (1/2 or 3/8?) and hope that I can coax the potato chip plywood flat, or would it be better to go w/ particle board or MDF?
I would imagine the thinner the table top, the more stiffeners I would need under it to prevent sagging. But more stiffeners means potential interference w/ under table accessories.
Suppose what I'm asking for are some opinions regarding table top materials, thicknessess and/or spacing of the cross braces under it. Is there a good balance?
BTW: Not interested in a foam top as I don't think it'll hold up w/ my son playing on it.