Foam on the bottom?

[Andrew Beasley]

WARNING Random waffle / brain dump ahead…

Over the years I must have spent wasted a fortune on foam trying to make modular boards that do not suffer from the giant crevasse at the edge but allow me to put rivers / cart tracks / ditches etc slightly lower than the normal ground level.

Like a lot of terrain builders I tried foams galore – the classic white expanded (now with black dots in it), blue soft (as in cushions – not bad for hills but I digress), blue firm, boxed, MDF edged etc but still the gaps remained…

The closest I came to a nice result was testing the Terrain Tile System from Sarissa Precision [their shop] and it’s wavy edge:

(Picture taken from Sarrisa and badly cropped by me).

But as you can see, rivers are made by adding smaller tiles on top of the base boards giving you a double height square / rectangle on the table rather than a lower river…

It’s also very shallow – only 3mm (plus a bit of glue) – fine for roads but a bit thin for rivers or ditches for 28s (not interested in trenches).

I did try a sample of sticking foam on the top and recutting the wavy edges but all attempts at this have failed due to the melting action of the cutter or my ineptitude in holding things flat enough to cut vertical edges.

Next I thought – stick two boards together and cut the river in the top one. Sad to say my woodwork skills have not gotten better since school (second worse subject) and despite cutting before glueing or carving the boards after glueing, the results where yuck – though I did keep all my fingers 🙂 Main problem was the tools I used (yes I know I chose them so ultimately it’s me at fault) but I honestly could never find the space for a 240v model makers scroll saw for the few cuts I needed and the normal home jigsaws would lead to hospital visits! Locally the ‘men in sheds‘ [their site] do not let you do your own projects and I cannot find another maker space this side of the Humber.

I also looked at just sticking the standard river sections to the boards and doubling all the others – I could master the odd board warp but TBH the rivers looked very regular and angular rather than the free flow I wanted and still shallow…

Last night it struck me – why not use foam UNDER the normal boards to raise them up and give me depth to carve into but retaining JUST the machined zigzag edge of the MDF?

I’m reasonable sure that:

• I can use a small hand fretsaw to cut the boards apart to give me edges for road / river tiles. It does not matter how rough these are as I can use filler to shape the edges.
• Making the foam slightly smaller than the boards does not matter as you will not see any of the gaps as they are underneath.
• The foam should be strong enough to hold together if I do not carve too deep and use the 5cm boards
• I am sure I can still pick up some sign makers plastic cheap to back them if I go for thinner foam.
• Chips and dints in the foam will not show (esp if I use the duct tape mentioned by Carojon in his blog [here]

This may be a lot of cost / work just to solve two issues:

1. No regular cracks in the boards
2. Reasonably deep (5mm+) river banks

One for me to mull over for a winter project I think.

Note I do have some resin raised rivers [Magnetic Displays] – look out for these in the Palaeo games at some point…

[Mike]

Andrew Beasley wrote:

Making the foam slightly smaller than the boards does not matter as you will not see any of the gaps as they are underneath.

I did this with cork tiles. Self adhesive cork tiles as that made it even easier.
Double tiles for normal. The tile underneath slightly smaller all around.
For river tiles just the edges with the river on need to be flush.

Worked a treat.

[Geof Downton]

I used thick, dense (possibly applies equally to me!) expanded polystyrene on Sarissa TSS  boards for my old testament era tomb complex. I glued the foam to the first base , with PVA, when dry I cut it with a thin rod hot knife thingy from Amazon, then aligned the wiggly edges of both boards and foam and glued the next bit, taking care to neither glue the recently cut foam back together, nor join the baseboards! It was my entry in the 2022 Build Something Competition on LAF, There is a picture on the thread there which may make my explanation clearer.

One who puts on his armour should not boast like one who takes it off.
Ahab, King of Israel; 1 Kings 20:11

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