Best type of plywood for layout base?

[stokesda]

Hey, y'all,

Forgive me if this question has been covered before. I did a couple of quick searches of the forum and turned up nothing after about 15 minutes and gave up...

I'm preparing to build my first layout. It's going to be a table style layout (i.e. not along the walls), and I'm planning to use 1/2" plywood surface with 1x4 framing. The track will be laid on cork roadbed. I chose not to use a layer of foam as my base, because I am trying to build it to survive through several moves in the next decade or so (I'm in the military). I'll probably use some foam to build small mountains and whatnot, though.

My question is: what is the best TYPE of plywood to use for the layout surface? I've heard that it's good to use exterior-grade, because it better resists damage from water-based scenery materials. I've also heard that it's good to use cabinet-grade plywood, because it's better quality and less prone to warping than "regular" plywood.

I could be wrong, but as far as I know, there is no such thing as exterior-use cabinet-grade plywood. Any thoughts or advice? Thanks in advance.

Cheers,

[davekelly]

I think 1/2 inch may be a little overkill. I've used 3/8 with good success. You'd be surprised at the weight difference between the two!! I've used B/C interior plywood. While I never thought about it, I don't think exterior is needed as I doubt you'll ever use so much water on your scenery that interior grade would be threatened. The quality of cabinet-grade plywood cannot be debated, but given that this is your first layout it might not be necessary. Not that you shouldn't use high quality materials, but if you are like all the other model rails I know, you'll rebuild portions of that first layout so many times that within a couple of years, none of the original plywood will be left!

[jwar]

Hi Dan

I used 1/2 for my yard and have no problems, My friend used 1/4 ply with lots of under bracing and his works great with no sags. I would use ply sanded on one side only, the thickness you will have to decide on after checking weight and ease of shipment.

I knew a person that built a layout in the service with shippin as his first thought. I was a 1x4 x8 foot box when I first seen it. He designerd the legs to internaly fold in, storage under the layout base and a plywood cover that was the other half of his 4x 16 ft layout. We spent many a night in Korea having a ball with it.

Good luck and Thanks for Serving....John

[Bikerdad]

Truthfully, the best type of sheet goods (plywood, particle board, MDF, oriented strand board, panelling, etc) to use for a layout would be MDO. MDO is "Medium Density Overlay", a plywood designed specifically for painting and outdoor use.

QUOTE: MDO Plywood - The Paintable General Purpose Panel
Characteristics: An EXTERIOR type plywood with a weather-resistant resin overlay bonded to the wood by heat and pressure. This process fuses the molecules of the overlay with the fibres of the wood to form a bond as strong as the wood itself. MDO has all the advantages of regular plywood as well as additional proprerties. The overlay, which has 28% resin content, resists water, weather, wear and degradation. It has texture that paint can grip with remarkable tenacity. Paint finishes on MDO are up to three times more durable than the same finish applied to ordinary plywood.Ideal for Painted Signs: In many instances, overlaid MDO plywood has proven a more durable sign material than metal. MDO plywood is resistant to the elements with no danger of rust or corrosion.

http://www.canply.org/english/products/overlaidplywood.htm

[Anonymous]

I will offer a counter opinion. I think 1/2" is not overkill. I am using 3/4" cabinet grade on my layout. Expensive but nothing moves, sags etc. The question is how will things hold up over time. I used 1/4 and 3/8 on my last layout and had problems with warping and sagging. Sure you can support the heck out of it, but it may be just as easy to go thicker on the plywood. The reason I use cabinet grade is that it is high quality, and has a flat surface. I don't know what has happened to plywood in the last few years but at my lumber yard the cheaper grades are seriously warped, "potato chip" is the term in the trade.

As long as the layout is not large, the cost difference between the good stuff and not so good stuff is minimal. If I were looking at building a portable layout I might take a look at David Barrow's domino idea for bench work. He has done numerous articles on the subject for MR through the last ten years. The basic idea is to build a series of stand alone sections say 2' x 4' that bolt together. It would be a lot easier to move a layout constructed in this manner than say a 4 x 8 sheet with legs...

[grayfox1119]

I agree with you Guy. In fact, I just purchased 2 sheets of 3/4" plywood today. It is very smooth on top side, and flat as a pancake. I have read many threads before deciding on what to use, plus my own experiences over the years has taught me NOT to try to get away cheaper. The base holds all your value. If you use something like 3/4", you have both strength and durability, you could kneel or stand on these bases if you ever had too, and if it were necessary to move your layout, 3/4" can take the abuses of moving. I paid $28.50 per sheet. How much does ONE engine cost? Or ONE turnout? It doesn't make any sense to me at all to go lighter on something that you will always have. For legs, I am using 2x3's, as they had a real good sale on some excellent stock. $1.97 ea. I also use deck screws to assemble everything. No pounding nails, or nails lifting over time, screws stay put, end of story! And, if you have to add-on or take apart, screws back out easily...but nails? Try pulling and banging on your layout trying to get those suckers out....no way Jose!!! Good luck with your layout Dan....

[selector]

I used 5/8" plywood G1S (Good on One Side). It is plenty heavy (go find out for yourself), plenty stiff, and cheaper than 3/4". Needs strapping or some other type of support every 3 feet to be sure of keeping it flat.

I really feel that 3/8" is a bit thin for my tastes, but if supported every 14-18", it should be fine, and probably a good compromise between portability and durability.

[Adelie]

I'm using G1S 1/2" for mine, and it seems fine. If I remember, I bought birch last time. I've used 3/4" before with good results. Mine is supported every 16", even tighter is some spots (more related to obstructions for the benchwork than the subroadbed). For anyone who does not know, 3/4" is used for subflooring in home construction, at least around here. So, your refrigerator is sitting on it!

I may bollux this up, but I read some time back in a model railroad building book that plywood should be 5-layer for strength. The 1/2" I'm getting is 5-layer. I think all 1/4" is 3-layer, and 3/8" may be as well. It's pretty easy to tell when you look at the edges.

[dknelson]

I use 1/2" but I follow the Dave Barrow "domino" technique of building layouts using interchangable 2 ft by 4 ft segments. I purchased ready cut plywood of that size at a local big box type store called Menards. They store it indoors, and they store it flat. When I bought a 4 x 8 sheet at a lumber yard and had it cut to size, I found that plywood was much more warped even though it was a good quality. It had been stored on its side and in an outdoors shed.
By the way I also store the wood in my basement for a good long time before beginning construction and I also store it flat. By the time I build a domino sometimes the wood has been in the basement for two or more changes of season. That helps control warping (ditto for homasote although i also shellac my homasote to control warpage)

The dominoes involve a frame of 1x4 lumber and I use plenty of drywall screws and have had no problem with warped wood.
Dave Nelson

[davekelly]

The domino technique seems to be a winner for those contemplating frequent moves. Although I suggested 3/8 inch plywood, I do agree that 1/2 or 3/4 cabinet grade is excellent. Of course the key to which to use is the amount of bracing and distance between braces. Another concern for weight is whether the whole layout will be covered in plywood or will the plywood be just used as subroadbed. Everything is a trade off.

I would also suggest that if one is going to go the domino route with an eye towards frequent moves, each domino be made slightly less than 2 by 8. That way a protective "box" can be made out of a standard piece of plywood that can be fitted over each domino and secured to the framing with bolt/nuts. That way come moving day the layout can be turned into a set of same size plywood boxes.

[cwclark]

yes, i don't think 1/2" is overkill at all..in fact i don't think it's thick enough..one of the layout's i built worked fine with 1/2" until i started using it cut into 2 1/4" sections of roadbed...after a few years it began to sag enough to cause coupler problems..I used 3/4" from then on..it will never sag unless it stays wet for about a month but i'm not planning on letting the roof on my train room get that bad to let the plywood get wet...[:D]...Chuck

[stokesda]

Thanks, everybody, for all the good advice. I think I'll stick to cabinet-grade plywood - maybe 1/2" or 5/8"

The finished layout will be 5 x 9, so I had originally planned to make it in two 4-1/2 x 5 halves that I could la***ogether in a protective "box" arrangement for shipping. Now I'm thinking maybe I'll do four 2-1/2 x 4-1/2 quarter-sections so it can be shipped in two smaller and lighter "box" assemblies instead... We'll see - I'm still in the planning stage right now...

Cheers,