It seems that more and more model railroaders are ripping plywood for building benchwork instead of using regular wood. Can someone please tell me pros and cons?
Plywood is a laminated product, consisting of several layers glued together with the grain of the wood alternating with each layer. The theory is that because of it’s construction, it is more structually stable than solid lumber. The recommendation of the people who advocate this approach is that you use 7-ply, or furniture grade plywood, rather than the conventional 5-ply construction grade material. I have never actually used this method, as I think that the L-girder method of benchwork construction would be just as stable, providing that the girders are properly glued and screwed along their entire assembly. But that’s just my opinion.
In the northeast USA, 3/4" AC Doug Fir plywood is about $30-35 per sheet. This will yeild 12 1"x4"x8’ (approx) pieces. #2 pine or poplar - the equivilent in quality - is approx $8-10 per piece for 1"x4"x8’. Aside from the $50 or so savings in price, the plywood will almost never warp or twist if in a reasonably dry enviorment, or primed/painted - pine or poplar sometimes will. BTW, 1"x4" pine/poplar is actually 3/4"x3 1/2" - an archaic way we have of sizeing lumber. Of course you have to rip it yourself, which requires a GOOD QUALITY table saw - not a $99 wonder, or you have to pay the lumber yard/big box store to rip it. Home Despot (not a typo) gives you 2 free cuts, then charges $.75 per additional cut (this will vary by location) so you have 10 additional cuts for $7.50 - still cheaper than pine/poplar. If Lowes/HD does the cuting, their specs are +/- 1/4", so the pieces may not be exactly the same width. If you are doing a large layout, or have other projects around the house to do, a good quality - $300+ - table saw is well worth the investment - a $99 saw will burn out after 1 to 1 1/2 sheets of 3/4" ply!! My [2c]
Edit: Cabinet grade is not required for the necessary stability, std 5 ply is OK - 40+ years as a carpenter/cabinetmaker.
Plywood is less likely to warp, wind, shrink, or swell than “dimensional lumber” aka 14 pine. The dimensional lumber will be a lot stronger because all the grain runs along the board, where as half the grain in plywood runs the wrong way, crosswise, yielding very little strength. My benchword used 1/2" plywood sheets to support the 2 inch foam with 14 pine framing around the edges to protect the edges of the foam.
You will have less shrinkage or swelling if you let the lumber adjust to the humidity of your train room. Stack the raw lumber in the train room for a couple of weeks before you build with it.
For a classic Lynn Westcott style L girder with joists open benchwork I would go with dimensional lumber rather than strips of sawn plywood for strength. The L girders in particular want to be strong enough to support your weight for that inevitable gotta-climb-on-the-layout-to-reach-something moment. I fear plywood isn’t that strong.
Plywood comes in a lot of grades, running from cheap, lots of knotholes, low strength wood, rough and splintery up thru very expensive no knotholes anywhere, any layer, cabinet grade hardwood every layer, sanded smooth on both sides. The cheapest grades are worthless for model railroading. Real lumber yards carry better grade lumber than the big boxes do. Cut edges of plywood are ugly and won’t look well until they are covered with something.
Rassling 4*8 sheet plywood thru a table saw is quite a trick, especially single handed. I lay the plywood on sawhorses and cut it with a skilsaw. Clamp a straight board to the plywood to guide the skilsaw and your cut will come out straight and neat. Use a carbide blade with a lot of teeth. Or a special plywood blade.
Both very good points
There is a current thread in the Layout Building forum that you will probably find very helpful:
http://cs.trains.com/forums/1489391/ShowPost.aspx
Basically, I just started construction using 1x3 pine lumber. Many folks on here and at home told me I would have problems with sag. By switching to ripped plywood, the dimensional stability of the plywood will insure I will not have sag issues. Mind you that the particular design of my wall brackets is what is causing this issue; for most other benchwork designs, plain ol’ dimensional lumber works just fine. For example, with my pine brackets, I could have added additional supports to solve the sag problem, but then I would have had benchwork in places I didn’t want benchwork.
Jamie
MOST ‘big box’ stores will rip the ply for you on a ‘per cut’ basis. I paid $O.35 PER. I came in with a drawing of how i wanted it cut. Wham Bam, thank you mam.
Beats spending $400 on a ‘table saw’.
Instead of plywood, I used good quality particle board. I bleive the partlce board has better qualities than plywood. The layout is built in sections so that it may be moved at a later date if necessary. Cabinets for storage are made of the same material.
Nice, neat-looking benchwork Garry, but in my dictionary, this is one of the examples used to illustrate an oxymoron. [swg] Particle board is heavy, doesn’t hold screws well, especially if you plan on disassembling and re-assembling things, and, under load, face-glued joints will cause internal separation of the material.
As noted earlier, plywood can be easily ripped using a straight-edge and a Skilsaw. It’s a good idea to pre-drill for screws, though, especially for joints into edges. I prefer #1 or select pine, in 1"x2" or 1"x4" sizes. The actual size of a 1"x4", by the way, at 3/4"x3 1/2", is because of the planing process used to finish the boards: at one time, all dimensional lumber actually was the size that it claimed to be. You may still be able to get “true” sizes by special order, although the faces will be extremely rough. True 1"x12" pine is readily available, though.
Wayne
I would NOT USE particle board if my life depended on it!!!
Particle board is particularly susceptible to moisture, it absorbs moisture and swells. When moisture is removed, it does not shink. It crumbles and deteriorates. Screws or nails will rust and work loose.
How do I know? my floors are particle board and even though it is insulated/heated/air conditioned/dehumidified the floors in my house are a problem. Where the 4 x 8 sheets of particle board meet, there can be issues in height. The middle of a 4 x 8 sheet can bow and raise nails and work screws loose. I have replaced some flooring with 3/4 inch plywood. Much better.
my [2c] based on experience.
Another drawback to particle board is that the glue is very attractive to rodents. I have had the particle board portions of funriture attacked by rodents that left the real wood completely alone. Ruined the back and legs of an otherwise very pretty dining room hutch. In another case, a hole was eaten completely through from the bottom side of my cheap work bench, and the shelves of my Gorilla racks took a hit, too. And of course, everything under the particle board got a coating of dust.
As I said in a post on cork roadbed, I equate cork and particle board. They have very few redeeeming qualities other than being (very) cheap substitutes for something better. Neither has been successful for me in the long term.
Just my experiences - I realize others use these materials successfully. I haven’t.
Fred W
Plywood legs may well be the way I go next time but I would be sure to put feet on them because water can cause it to delaminate. Some of us don’t have dry basements.
Plywood is plenty strong for L girders. After all they make airplane wings of plywood.
Really the major drawbacks to plywood construction is getting the pieces cut, the edges can be a little splintery and they aren’t quite as strong when edge screwed as stick wood. In every other way they are superior.
I have used stick wood for my layout but have helped several others build theirs from plywood.
Dave H.
After building with dimensional lumber–and spending far too much time trying to find some that wasn’t curved (a lot looked like you could lay a boat hull with it!)–I finally went the ripped-plywood route and was very, very pleased.
Straight pieces of lumber make building benchwork very easy! I have the dealer cut it for me; at 25 cents a cut, it beats dealing with huge sheets of lumber on my basement table saw, and the the cuts are nice and straight, too.
I still use 2x2s for legs, and finding straight pieces is a real challenge. But for the rest, I’ll never go back to 1x3s or other dimensional lumber.
And, no, I don’t use, nor would I recommend particle board of any kind. It’s too unstable for my tastes. Cheaper, sure, but you really do get what you pay for in this arena.
Very well said! In fact, I went down to the basement today to take a look at the wall brackets I built with 1 x 3 pine a few days ago. Now mind you, I purchased the bundles of 1 x 3s over a month ago and they have spent the time since then getting happy in the climate controlled basement. When I built the first four brackets the other day, they were all nice and square. This morning, I held one up in position and with the top end flush against the wall, the bottom was about a full 3/4" bowed out. At first I thought that spot had a bulge in the wall, but I held another completed bracket up in the same position and it was flush all the way. So, in just a few days, I have had one of the four brackets warp on me. Feelin’ better about the decision to switch to plywood every day! Jamie