Uses for flexible MDF

[idlemarvel]

I bought a piece of flexible MDF from Wickes to make a tunnel, and I had a few ideas about how it could be used for g-scale scenery. Basically it has horizontal slots about 1mm wide with 5mm between slots, about 3mm deep. 5mm is about 4 inches in the scales we work in, so if you think about all the thinks that are about 4 inches wide in real life, like bricks and planks, you can get some idea.

Picture above shows the raw material top left, at attempt at making decking or perhaps barrow crossing top right, brickwork bottom left (used a screwdriver blade to make the vertical slots) and clapperboard bottom right (used a craft knife to chamfer the top edge of each "plank"). With the brickwork and clapperboard I used fine polyfilla to lessen the depth of the slot, and with the brick I left a fine layer on top to represent the texture of bricks.

I just used felt tip pens for the colouring to get a quick impression. MDF absorbs water like a sponge, so for outdoor use you would need to varnish the end result.

 

[playmofire]

Interesting. How flexible is it for, say, a single track tunnel?

 

[David1226]

I know people who bend over backwards to be flexible

David

 

[dunnyrail]

Rather Like the Brick Effect, but not sure though how well it would survive in the Great Outdoors. My problem is that I hate having to being anything in after an Operating Session other than Rolling Stock. So Plastic, HIPS and Bulding Blocks are the thing for me.
JonD

 

[idlemarvel]

Interesting. How flexible is it for, say, a single track tunnel?

I would say the minimum radius is about 150mm. More than that and there is a danger of snapping. It comes in 600mm x 1200mm lengths (from Wickes, there are other suppliers) and the slots run along the short length. So you can form a single track tunnel quite easily.

 

[playmofire]

Thanks for the info; most useful.

 

[playmofire]

A bit of research on tunnels for G scale suggests the following internal dimensions.

Height 10 to 10.5 inches, 250 to 263mm

Width 7.5 inches, 188mm

However, if flexible MDF can only be bent to a minimum radius of 150mm (6 inches), then it's no use for a single track tunnel as a 150mm/6 inch radius would be 300mm or 12 inches in diameter/wide. IN addition, having tried bending some flexible MDF at B&Q this morning, getting near its minimum diameter there is tremendous outward pressure which would need to be contained.

I think what is needed is a pipe with a diameter of about 7.5 inches or metric equivalent which can be cut in half laterally to give a curved section 7.5 inches wide and 3.75 inches high which can then be fitted onto side walls about 6.5 inches high and then maybe covered with expanded foam.

 

[idlemarvel]

I take your point that you may have to be generous for the width of a single track tunnel, but remember the need for the "hand of God" to access failed or derailed trains! Also as other people have mentioned MDF is not much good for outdoor use; I was using it for a quick solution for my small indoor layout which is full or R1 curves.

 

[playmofire]

I take your point that you may have to be generous for the width of a single track tunnel, but remember the need for the "hand of God" to access failed or derailed trains! Also as other people have mentioned MDF is not much good for outdoor use; I was using it for a quick solution for my small indoor layout which is full or R1 curves.

I was thinking of it for indoor use on the straight, notably at next year's Kirkbean exhibition, and just lifting it clear in case of derailments etc.

 

[MyMiniatureWorlds]

Really like the "brick look"

 

[Northsider]

I've used flexi-MDF a fair bit; if you laminate it with 0.8mm ply i.e. make a ply/MDF/ply sandwich, using PVA glue, it will hold its shape and be strong enough to take some fairly rough handling. But MDF is useless if it gets wet: the fibres expand and the resin holding them together fails, resulting in a 'blown' piece of material. I have used MDF (and modelling clay) for buildings, but bring them in after each running session.


You can get flexi-ply, but this doesn't form such a tight radius, and although it is a bit more water resistant, it still isn't waterproof. I've used it to provide the structure for a curved viaduct, but this also comes indoors at the end of running.