A foamboard baseboard

[Ian McAulay]

I thought a couple of notes and photos of a baseboard built using foamboard might be of interest.

First of all a confession: this construction isn't what I set out to do. I was actually planning to use foam cored PVC board, the kind of stuff shop signboards are made of, which is PVC on both surfaces and PVC foam in the middle. My Amazon search kicked up more than one product and I didn't buy what I thought I was buying!

So the product I used was actually the type of board that has two card surfaces and polyurethane foam in the middle. It comes in 5mm and 10mm thicknesses. I used 5mm. The leading brand is Kapaboard, although the brand I used is Simplex.

The attached photos show the story without needing much explanation.

I bought a pack of 10 sheets of A1 size board, that's 841x594mm. My overall dimensions were 1188mm square, twice the short side of the foamboard sheets, so the top surface is made up of 4 squares of board. The stiffness of the structure comes from the sections of board forming the framework. They are all 120mm deep, set on the half and quarter points in each direction (giving a bay size of nominally 297mm) and all diagonals. (The diagonals are important: they give the structure torsional stiffness.)

You should be able to see that each of the frame members has a 50mm diameter hole cut in it to accommodate wiring. These were cut very easily using an Olfa hole cutter, which is essentially a pair of compasses with a knife blade instead of a pencil.

The glue bottles in two of the photos reveal that the whole thing is glued together with good old fashioned PVA wood glue.

While the foamboard provides a rigid lightweight structure, it has very little resistance to impact damage. To deal with that, I used 2mm MDF, both as patches to protect the major frame joints from crushing and as a facing along all 4 sides to protect against knocks. I added pieces of L section softwood moulding at the corners, partly for a little more knock resistance and partly for neatness.

(2mm MDF isn't a thickness you commonly see in DIY shops, but I have a friend who is a gallery owner and picture framer and who uses it as the backboards for picture frames.  He also has a guillotine for cutting this stuff, producing better cuts for the edges than I could ever hope to do with a Stanley knife!)

The overall weight of the board is about 3.4kg (about 7.5lb in old money), made up of 2kg for the foamboard and 1.4kg for the MDF.

I'll be interested myself to see how this baseboard construction fares in use. I'll report on that in due course.

Ian

[Hugh Norwood]

I forgot to mention on Wednesday that Angst's baseboards are 5mm foamboard - but I laminated two sheets together for each one - so they are effectively 10mm thick. I've only had a marginal issue with dishing over its active life so far (over 10 years) and that is really due to me not working out how to do the edge properly where the two boards join together!

[Graeme Dunbar]

Is the foamboard clad in something to protect it like Ian did with thin MDF, Hugh? If so, what did you use?

[Ian McAulay]

I forgot to mention on Wednesday that Angst's baseboards are 5mm foamboard

Hi Hugh

Useful to know someone using the same material. Mine is a single board layout, so I don't have to worry about connecting boards together.

Ian

[cp.409067]

*

As someone who has built a part foamcore board layout and continues to experiment with the material for such use may I add the following comments?

[1]  Ian McAulay's admirable baseboard appears to be built using black foamcore board. Whilst black (and also grey) are available they are somewhat more expensive than plain white.

[2]  Taking the Hobbycraft stores (no doubt other suppliers have different prices) as an example -

https://www.hobbycraft.co.uk/advancedsearchresults.aspx?query=foamcore%20board&utm_campaign=search-from-google&utm_source=google&utm_medium=Organic

- a single A1 sheet of 5mm thick in black is £7.70, whereas the same size and thickness in white is £4.00, or indeed on offer at 4 for £10.00.

[3]  At the price of £2.50 a sheet, and given the ease of working the material, it is something which one can easily afford to use on an experimental basis.

[4]  As well as 5mm and 10mm thicknesses already mentioned, foamcore board is also available from some suppliers in 3mm thickness.



CP

[Hugh Norwood]

Is the foamboard clad in something to protect it like Ian did with thin MDF, Hugh? If so, what did you use?

Only the surface of the baseboards are foam board; they are stuck to a frame of hardwood strip 12 by 54mm which in turn is braced with some aluminium angle (I may have over-engineered the frame a bit!) The frame goes round the perimeter of each board and there is only one (full) cross-brace on each one.



The exposed edges of the foamboard are protected at the front by the dockside walls, at the ends by the sides which form part of the  "crate" as well as the scenic ends - and at the rear by a thick card wall that prevents locos and rolling stock being knocked to the floor...

[Graeme Dunbar]

Thanks Hugh. The use of aluminium angle looks interesting and a good way of adding stiffness to the sides.

[Ian McAulay]

Hugh: Ingenious combination of materials. My choice of foamboard was accidental as noted in my first post, so I'm experimenting here. It's instructive to see how others are also making use of less conventional materials.

Christopher: Black wouldn't have been my first choice if I knew what I was buying - see slightly embarrassed second paragraph of my original posting. If I had actually set out build the structure I have in fact builf, it would have been white, not least so that wiring notes could be pencilled on. Hobbycraft is an excellent shop (one I use often) but pricy for some materials, especially if you need a lot of it. I bought a box of 10 A1 sheets (and used 8 and a half) from Amazon. A box of 10 white A1 sheets comes in under £30.

I've built similar baseboard structures in the past using 3mm ply, relying on depth of framing and a full set of diagonals to achieve rigidity and torsional stiffness. The result is nice and light, but still heavier than the foamboard. (Also rather noisy, even with 3mm cork under the track!)

Ian

[James S]

Great to see different foamboard experiments.

I used it on my layout Buchan (https://www.009society.com/forum/index.php?topic=4505.0) albeit with a somewhat less geometrically pleasing design!

The longevity will be interesting to see, although I've had some positive feedback from others on that score.

[Ian McAulay]

I used it on my layout Buchan (https://www.009society.com/forum/index.php?topic=4505.0) albeit with a somewhat less geometrically pleasing design!

The longevity will be interesting to see, although I've had some positive feedback from others on that score.

Yes, the geometry is a little obsessive, I admit!  ;D

It's had a few thumps just manhandling it around the railway room and our spare bedroom, but the MDF protective layer has done its stuff so far. If I ever exhibit it, that will be the REAL test!

Ian

[Chester 009]

I am considering using an A1 piece of foam board for a small layout, with a basic wood frame underneath, and have read the earlier posts.

I have three questions:

1) What adhesive is best for attaching the foamboard to wood? (Perhaps with a few thin nails or screws?)
2) What adhesive is best for attaching Peco track to the board?
3) Will the foamboard hold carefully used track pins? I am thinking about small radius flexitrack curves (16-18 cm radius), so the pins will be needed until ballasting 'fixes' the track in position.

[cp.409067]

.....

1) What adhesive is best for attaching the foamboard to wood? (Perhaps with a few thin nails or screws?)
2) What adhesive is best for attaching Peco track to the board?
3) Will the foamboard hold carefully used track pins? I am thinking about small radius flexitrack curves (16-18 cm radius), so the pins will be needed until ballasting 'fixes' the track in position.

*

In the above order based on my experience.

[1]    PVA. Nails and screws will tear the foamcore board.

[2]    PVA using (say) push pins and weights to hold the track in place whilst the glue sets.

[3]    No. But as above push pins will hold the track initially and then the ballast (if also fixed down with PVA) will act like the real thing.


CP

[Graeme Dunbar]

Definitely glue and not nails or screws. The issue is that nails and screws concentrate the loads at (almost literally) pin-point locations whereas gluing makes for a monocoque construction.

I've used PVA, some people use hot-melt glue but I am a recent convert to UHU Por (foam-safe) gluing following recommendations from radio control model aircraft building friends. UHU Por has less obnoxious fumes (using foam-safe solvents) than most contact adhesives. PVA is less expensive though.

https://www.uhu.com/en/product-page.37252

Shop around online for a good price. It varies quite a bit though model aircraft shops can be good as they shift a fair amount of the stuff.

Have you considered a complete foamboard construction, or at least just wood for outside frame where it will be bumped and internal cross-bracing with foamboard? A good thing about the material is that it is so easy to cut that odd sized and placed stiffening members can be cut to avoid point motors and so on.

[JulienW]

Whilst I've yet to try making a baseboard from the material (yet!) I have used foam core board as the carcass for large industrial buildings that have been clean in slaters plastic sheet. I've used both PVA and holt melt glue for fixing the walls together, usually using pins (I have a box of brass lacemaking pins) to hold things together whilst the PVA sets or I run a bead of hot glue along the joint. Once they have done their job the pins are removed.

[Ian McAulay]

I concur with Christopher and Graeme; PVA (I use good old Resin W) is just perfect for foamboard to wood. What you are actually glueing is the paper outer shell of the foamboard and PVA is perfect for absorbent surfaces like that.

If you look at my progress shots at the top of this thread, you will see that the foamboard structure for my layout is protected from impact by judicious use of 2mm MDF. PVA works fine for this with a little bit of weight to keep the joints tight as the glue sets.

The attached photo shows current progress. My layout is an island with the lowest track level elevated by 25mm of polystyrene foam. I'm actually going to pin the track down, but I have 5mm foamboard + 25mm polystyrene foam + 3mm cork + 3mm sleeper base to go through, 36mm in total. I will be using 30mm stainless steel dressmakers' pins to secure the track, but there is a lot of depth to grip the pins. If I was laying track direct to the foamboard, I think I'd use glue.

Hope that helps

Ian