The New Northern Central

[Steveruger45]

If going with a quality (not CDX) plywood I think you could safely go down to 1/2” if supported transversely every 16” by a bracket and 1x3 and as long as you have some MDF or hardboard facia glued and nailed along the plywood ends.  I think I would still put one long brace between each bracket/transverse at the back though.

[wm3798]

And guys, have you priced plywood lately?
3/4" cabinet grade plywood is probably $80 to $100 a sheet.

I'd get some 3/8" BC and some 1x2s to add a bit of frame.  Glue and screw it to the frame and call it Christmas.
Lee

[DKS]

As a resident of the northeast, with its tendency for swings in temperature and humidity, I'm kinda surprised you're considering any wood-based benchwork. Me, I'd hit the steel stud section of Home Depot, get a few tubes of caulk, and glue 2" slabs of insulation onto a steel frame. Probably not as economical, but it'll provide dimensional stability.

[dem34]

As a resident of the northeast, with its tendency for swings in temperature and humidity, I'm kinda surprised you're considering any wood-based benchwork. Me, I'd hit the steel stud section of Home Depot, get a few tubes of caulk, and glue 2" slabs of insulation onto a steel frame. Probably not as economical, but it'll provide dimensional stability.

That sounds quite overkill even for larger scales. If anything I would suggest he bump that plywood thickness to at least a 1/4, and by doing that and keeping no more than the spacing of the studs between brackets he should have a fairly stable profile. That also said, only having ply as a sub roadbed does kinda limit scenic options, unless he plans to jigsaw out sections for embankments and gap crossing.

[garethashenden]

There was an article in, I think, Model Railroad Planning on using steel instead of wood for the support structure. Because steel is so much stronger than wood, you need fewer supports and the ones you need can be smaller cross sections.

[C855B]

As a resident of the northeast, with its tendency for swings in temperature and humidity, I'm kinda surprised you're considering any wood-based benchwork. Me, I'd hit the steel stud section of Home Depot, get a few tubes of caulk, and glue 2" slabs of insulation onto a steel frame. Probably not as economical, but it'll provide dimensional stability.

This.

[DKS]

That sounds quite overkill even for larger scales. If anything I would suggest he bump that plywood thickness to at least a 1/4, and by doing that and keeping no more than the spacing of the studs between brackets he should have a fairly stable profile. That also said, only having ply as a sub roadbed does kinda limit scenic options, unless he plans to jigsaw out sections for embankments and gap crossing.

Hardly overkill. Steel benchwork is extremely lightweight, and goes together like lightning (just a few tools required). Indeed, I would never consider using any wood products for benchwork again after I filled a 25 x 35 foot space with it in 1998, over the course of just a week. The materials weigh a tiny fraction of what wood does, produces virtually no waste material (as in sawdust, etc.), and has very high dimensional stability. Just ask @C855B

[Ed Kapuscinski]

Yeah, but I want a plywood base to easily affix stuff to it, so I'll be on the wood wagon no matter what, so I might as well just stick with what I know.

[CRL]

If I was building a very large layout, it would probably make sense to acquire the tools & learn how to work with metal studs. But since my relatively small layout will be mounted on wall brackets, I feel more comfortable working with wood. I will use a foam base with small plywood pads glued to the foam wherever I need to mount something.

Old dog... resistant to new tricks.

Actually, I’d build the entire layout out of foam if I could.

[Dave V]

As with all things model railroading, you'll have a full spectrum of advice from which to choose or to ignore.  If using wood I highly, highly recommend priming and painting all of it to seal it...it won't solve all your expansion/contraction issues but will certainly lessen them.  This means both sides (and the edge) of the plywood, and all of the structural dimensional stuff all the way to the floor.

I built the RGS on shelf brackets with 1x2 frames and 5 mm plywood with a 4" foam topper, but I don't have a fraction of the humidity swings you do.  However, on the two peninsulas I used good old-fashioned L-girders.  Again, anything to keep wood as stable as possible.  It won't do for you what metal benchwork will, but it's certainly a step in the right direction.

[Chris333]

Ed finally wants to use wood for his benchwork...

No you're doing it all wrong 

[packers#1]

You know what is lightweight and won’t expand and contract like wood?















Foam




 

[C855B]

I'm not wanting to pour gasoline on this discussion, really. Ed knows what he's doing. However... 

In the four years of operating of - currently - ~500 feet of track, there has been not a single pop, not one kink, never an out-of-gauge, etc., etc., etc. ... typically the stuff that tends to result from normal expansion, contraction, swelling and shrinking of wood framing and substrates in a large layout. That was the engineered objective, and waddayaknow, it's working out that way. I have documented annual humidity swings from 10% to 75%, and that's in a conditioned, well-insulated room.

Adding insult, I always defy the trackwork gods by joining my track tight, with no joiner gaps, which all the experts tell you not to do. Still, no problems.

Small(er) layouts tend to be more tolerant of humidity variability, tho' not immune. Large layouts are a different matter as dimensional changes are cumulative. What is a negligible 1/8" to 1/4" in an 8-10' frame becomes 1/2" to 1" in 36-40'. Something would have to give.

[marklin-au]

     Re Painting of  boards , remember that plastic paint remains penetrable where as  enamel paint forms a decent skin  that stops moisture from entering  . Paint both sides before erecting also any drill holes , screw  or bolt holes to make  it totally moisture proof  .  Yep more  time , money &  mess .


     Have fun ,

    Cheers   Tom in Oz .

[Ed Kapuscinski]

So there's been a lot of really interesting discussion about bench work, but here's my question: has anyone actually had problems with the traditional approach?