foamboard for raised trackbed in N gauge?

[Black Sheep]

I've got a nice and stable laser cut board assembled but all my track bed is to be raised up above this height on embankments, retaining walls and viaducts, being only N gauge it doesn't need to take much weight. 

 

I did try 10mm ply but it's warped badly after being cut so I'm now considering 10mm foam board with a bit of plywood re-inforcing for mounting servo point motors to the underside. 

 

Has anyone done similar? 

[Kris]

10mm foam board is likely to be a little too flexible without some serious bracing. The only time that I have tried similar was on a short board just for photos. The only way I could get the stability I needed was to put a foam board "beam" under the track bed board. 

[LBRJ]

How did you get 10mm ply to warp?

Do you mean it actually warped or is just "a bit bent/bowed"

[peter220950]

Foam board would need sealing first, I've recently had a bit of swelling of the paper facing when ballasting was carried out using pva/latex and water. I think it's strong enough, but run a spine of foamboard down the the centre line underneath.

 

Left to my own devices I would go with Styrofoam to the full depth, which could then be carved to suit the embankments etc.

 

Peter

[Salmotrutta]

I have used foamboard for my HOm mini layout and it does warp a little when wetted. However I "egg-boxed" it underneath for stability. In the US we have GatorBoard which is more durable and also there is also another one which is bamboo-faced.

 

I will be building my next layout from one of the faced boards.

[Barry Ten]

I've used foamboard for elevated sections in N and haven't run into any problems.

[Black Sheep]

 

Foam board would need sealing first, I've recently had a bit of swelling of the paper facing when ballasting was carried out using pva/latex and water. I think it's strong enough, but run a spine of foamboard down the the centre line underneath.

 

Left to my own devices I would go with Styrofoam to the full depth, which could then be carved to suit the embankments etc.

 

Peter

 

it's the plastic fronted foam board that I'll be using, not card. 

 

The plywood warped making the U shaped trackbed I had cut more like a helix with a small ski ramp on the end! Perhaps a higher quality ply would not have done so. 

 

With styrofoam to the full depth, what do you do about mounting point motors? 

Edited May 9, 2017 by Black Sheep

[peter220950]

 

With styrofoam to the full depth, what do you do about mounting point motors?

 

A small plywood patress mounted into a rebate in the foam will give a solid base on which to mount the motor, if the motor is to be below the track it's easy to form a recess with a stepped edge into which you can glue the ply.

 

Peter

[Black Sheep]

I have lots of points quite close together...

 

[peter220950]

Then maybe a large plywood patress! - Presumably you would have had similar problems with foamboard

 

It looks as if properly supported plywood would be a better answer in that case, if you just laminate ply to the foamboard it runs the risk of warping, ideally in that situation a foamboard/ply/foamboard sandwich might be better to stop it trying to curl, it's best to balance the layers when glueing big surfaces together as they expand and contract at different rates.

 

Given the large amounts of motors and wiring I would want to maintain access for maintenance, have you thought how that will work if there's a solid base underneath everything?

 

Peter

[Black Sheep]

my intent was that the wooden trackbed would unscrew from it's mounts and lift off but that there would be some access holes through the board to run wiring and get at it from the underside

[hayfield]

I think the answer is in the design, at my previous club a 7 mm layout was started, but the design of the boards was not up to the job. At the weekend at a local show I was talking to an exhibitor who successfully uses foam-board for baseboards, he states that it is fine provided it is braced properly. Exactly the same as with Plywood, it will not warp if sufficient bracing is used.

 

I had 3 thin MDF  baseboards which were stored in the unheated club rooms for 3 years, all 3 were painted with silk emulsion  both sides. No issues at all with warping

[DCB]

I used 3mm MDF 20 odd years ago and one thing it did not do was warp and cutting holes was quite straightforward, so maybe brace the foamboard with MDF?

[Black Sheep]

I'm thinking I may just go for MDF and varnish it to try and seal it