Using Plywood 1/2" vs. 1/4"

[richhotrain]

I use 1/4" plywood… under 2 layers of 2" extruded foam.

1/4" plywood I would never use by itself. Also as mentioned 2x4’s for the framework is WAY overkill. I use 1x4’s for the side rails with 1x3’s for the crosspieces and I still think I could get away with 1x3’s and 1x2’s and still be plenty strong, especially after the plywood and foam is glued on.

I build my boxes nominally to 2x4 foot sections, but if it will fit I keep the foam in one 8 foot piece (2 of the sections) since I’ve already moved one and find that a 2x8 foot section is no trouble to get out the door - and my layout is on the third floor. If I REALLY have to I can saw throught he foam and unbolt the pieces into 2x4 foot sections, but the fewer joints the better. 2x8 with the plywood and foam isn’t that heavy and it’s plenty sturdy. The legs and crossbraces bolt on for easy removal.

–Randy

Randy,

These are excellent points that I need to consider. Building a modular platform could be a real possibility.

Rich

[richhotrain]

I would ditch the 2X4’s anyway, paid or not, recyclable or not. I would use ripped 1X4 clear spruce or pine that has withstood at least a week in the basement/intended space without warping. You’ll lighten things amazingly.

Secondly, I would use 1/4", but if you are now feeling squeamish, I would try 3/8" ply. But, as suggested above, used as a base for 1" extruded foam, it would be great!! Try for supporting members below it every 12", on centers, and you should be fine.

-Crandell

Crandell,

Thanks for that input, but I cannot bear parting with all of the 2x4 lumber that I have accumulated, although the thought of 1x4s or 1x6s is tempting. I really want to avoid 12" on center framework. Even with my current 24" on center framework, it gets in the way of installing Tortoises.

Rich

[richhotrain]

Rich,

First off I agree with your 2x4 bench work I am of the school of thought it can never be too strong. I have seen several layouts where 2x4 construction comes i handy as the layout builders actually get on the layout to get to hard to reach places.That being said if you screwed and glued 1/4" ply to the bench work providing your support pieces are close enough together it may be marginally strong enough but with 1/4" it has enough flexibility that it will resonate sound liek a drum head. I use 3/4" as subroadbed in some places and for yard panels and some times I feel it’s a little overkill but like I said earlier it can never be too strong

Having constructed the framework out of 2x4s, legs included, that sucker is strong enough to serve as a bomb shelter, or at least act as protection against a tornado.

[richhotrain]

Rich have you explored spline on an open 1" x 4" open grid. That would be a real money saver. You could then use plywood ( heavier than 1/4" I would suggest ) in yard areas and fill in the landscape with cardboard strips and goop.

Here is a photo of my spline on 1" x 4" open grid. It is elevated in this photo as it is winding its way into the Rocky Mountains. If the layout was to be flat, just lay the spline right on the grid. The nice thing about spline is the transitions up and down and left and right are easy to do as the spline finds the natural easements almost by itself.

Brent

Brent,

I have not ruled out this method by any means. A lot to think about here.

Thanks.

Rich

[richhotrain]

Instead of reusing the 2x4s for benchwork, why not rip it in half and use it for legs?

Already using 2x4s for legs as well. Simply easier just to keep the 2x4s for framing. Sounding more and more like I should stick with 1/2’ plywood for the surface and not go to 1/4" plywood.

[richhotrain]

All,

Sorry for the multiple replies here. Not sure how to more efficiently respond to all of your individual responses to my original post.

I really appreciate all of the input and insights.

I do have a question about 2" foam board.

What wood framework is used with it and how do you secure the foam board to the wood framework?

For example, do you use caulk to hold 2" foam board to 1x6 boards by gluing the foam board on top of the 1x6? I know an awful lot has been written about this issue and, regrettably, I have always skipped reading about it until now. In my naivete, seven years ago, when I built my first layout, 1/2" plywood screwed onto 2x4 framework seemed like the logical way to build a layout. What did I know?

My other question is: what is the best way to secure a Tortoise to foam board, especially if the foam board is simply suspended on wood framework but without laminating the foam board to an underlying wood surface ?

Thanks again.

Rich

[4Steam]

I, getting ready to start the construction of my bench work for mya layout i plan on using 2x4 framing and for the legs with foam have a few different depths to choose from but i plan to glue it down with caulk on top of 1/2 plywood.Reason being my first layout was constructed using 1/2 plywood and 2x4s and like others said i enjoyed being able to climb up on it if i needed to with out having to worry about anything breaking.I plan on reusing my benchwork when i move the layout into our new house 5 to 6 years down the road.

If you cant tell i like to build overkill

Just my [2c]

[jamnest]

I use domino layout construction. I rip 3/4" quality plywood into 1 x 4 lumber to make the domino boxes. for my previous layout I used 3/4" plywood for the tops, but the new layout I have stepped down to 1/2" plywood for the tops. It works great and has not warped.

[Jimmydieselfan]

1/2’’ plwood is the way to go unless you are doing open grid . If your layout is not going to be moved , I would use 2x4’s. Especially if it is going to be big. 1X3’s are fine for a little layout, but for the bigger ones I would use 2x4’s for strength, I used 2x4’s on my 19’x 5’ x 7’ U-shape and it is as solid as a rock. Yes it is heavy but it isn’t going anywhere either.It all boils down to how strong you want it

[selector]

Sure, Rich, I understand. I guess I should correct my suggestion about the 12" centers…I had the ply in mind…only. With a 1.5" or more extruded foam mated layer, you would need centers closer to 30-36". The foam ply combo becomes pleasingly rigid if bonded well, and you would only need maybe one ‘joist’ across the centerline of a 4X8…just to keep the ply honest. [(-D]

As for framing foam and glues, making a sheeting type frame with some rigidifying cross members, or maybe some gussets, is all you need. Essentially, a cladding for the outer and lower surfaces of the foam…the non-modelled surfaces.

If you wish to affix the foam to the plywood nether surface, or if you simply wish to bond the foam to a milled wood frame with some cross-members below it for support, you can use plain-Jane acrylic latex caulk, but I have found Gorilla Glue to be stronger…and more rigid. You don’t need much of the GG, and it must be catalyzed with a sheen or tap water painted onto one of the surfaces or both.

-Crandell

-Crandell

[BATMAN]

Here is my 1" x 4" grid with 2" foam. I think using plywood in addition is a bit of over kill. I have climbed on mine by putting a 1’ x 2’ piece of plywood down to kneel on, so I didn’t dent the foam. I used PL300 to glue the foam to the wood, but next time I would use caulk as that makes it easy to remove from the wood so both could easily be reused.

Brent

[doctorwayne]

My first layout, a 4’x8’, used 1"x4" framing, 16"o/c, with a 1/4" fir plywood top. The track, brass flex on fibre ties, was laid directly on the plywood. The entire assembly was strong, stable, and long-lasting. [;)]

If you’re building a table-top style layout, 1/4" plywood should be perfectly acceptable. I don’t particularly like the idea of 2"x4" framing, but the weight issue is immaterial for a layout that’s 22’x42’. [(-D] Such dimensional lumber isn’t a very stable material for a layout, regardless of it’s bulk or strength, as it’s usually not very dry and nor especially well-finished either. As this stuff continues to dry and shrink, it can twist and warp in ways that can wreak havoc on trackwork. However, since yours has apparently been in use for some time, it may have stabilised. For others contemplating a new layout, the 1"x4" clear pine suggested by Crandell, or the ripped 3/4" plywood mentioned by James (jamnest) would be my choice for framing.

If you’re planning on open grid framework with plywood roadbed, 1/4" is way too light - 1/2" may work, but I used good-quality 3/4" and have had zero problems with warping, twisting, or sagging. Support is 16"o/c. When I finally get around to building the second level of my layout, I plan on using 1"x2" clear pine framing, 16"o/c, with a table top of 3/8" spruce sheathing plywood. The front (facia side) framing will be 1"x4" clear pine, with the rear members lag-bolted to the wall studs, and the whole shebang supported on custom-built angle iron brackets. [:D]

Wayne

[richhotrain]

My other question is: what is the best way to secure a Tortoise to 2" foam board, especially if the foam board is simply suspended on wood framework but without laminating the foam board to an underlying wood surface ?

Thanks,

Rich

[selector]

Dig out a well in the foam’s nether surface and insert a plywood plug, maybe 3/8" thick. Use the plug as a base for mounting the Tortoise.

-Crandell

[richhotrain]

Dig out a well in the foam’s nether surface and insert a plywood plug, maybe 3/8" thick. Use the plug as a base for mounting the Tortoise.

-Crandell

Thanks, Crandell. That is what I thought might be the way to do it. Seems like it would be tricky to align the Tortoise accurately under such an arrangement, not as easy as drilling a hole in a plywood surface.

Rich