Using Foamboard

JimmyB

JimmyB

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23 Feb 2018
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I have in the past used foamboard on indoor models, but after a couple of post on here on the subject I decided to give it ago outside. I am starting with something simple tunnel mouth side retaining walls, however my questing is about the protection of the "inner foam". The raw edges will have the unprotected foam and for the indoor models this is just disguised, however outside will it be subject to deterioration be the whether, and if so what solution do other users utilise!!
 
LGB-Sid

LGB-Sid

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19 Sep 2016
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When you say Foam board is this the PVC foam board ? I have made all my outside building from PVC foam board and have not done anything special to the edges, but all my buildings are painted in car paints.
 
JimmyB

JimmyB

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23 Feb 2018
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Sid, Yes it would seem to be, pcv or similar on the outside, so just a good coat of a suitable exterior paint, many thanks.
 
mike

mike

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I wouldnt use the holow core foambord out side...the stuff i use is solid foambord...not the similar sandwich kind . I use pound shop rattle cans of car gray prima as a overall undercoat...then humbrol enamel paint to finish it
106333_286103aa54bdb0278bcb97280c916ab1.jpg
 
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Zerogee

Zerogee

Clencher's Bogleman
25 Oct 2009
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Jimmy, I think the stuff you're thinking of is what is usually called foamCORE, which is a relatively soft expanded foam centre sandwiched between two layers of thin card.... it is not weatherproof and not really of any use for outdoor structures. FoamBOARD, on the other hand, is a rigid homogenous sheet of much denser material - often used for things like Estate Agents' signboards - that is what Mike and others use for their outdoor buildings.
Don't mix the two up when buying.....

Jon.
 
JimmyB

JimmyB

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What I bought was sold as foamboard, a lightweight foam in the centre, and a plasticard/pvc outer-skin. When googling foamboard, what I have bought is what appears on the results!!
 
a98087

a98087

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8 Nov 2009
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Both types appear under the name foam board, foamex is one brand name for the solid stuff.

It is sometimes found under shopbought pizzas, but it’s just as easy to buy the sheets on ebay or from a manufacturer
,
With postage , buy the biggest sheets and bundles you can, as a4 sheets are a bit small in g scales
Here’s a relevant video that appeared on my YouTube this morning


My advice is reinforce the corner joints, and make the base nice and wide to ensure stability,

Dan
 
JimmyB

JimmyB

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Dan, many thanks, seems to be a bit of a crossover between foamboard and foamex
 
S

Sarah Winfield

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I'm part way through watching the video, thanks for posting.

Which particular brand of superglue are you using please and what it in the spray can?

I'm amazed you don't seem to stick your fingers together or to the model.

SW
 
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Timbo

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12 Apr 2016
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Hi Jimmy,
I am using what appears to be polythene foam. It used as insulation for roofs and other areas here in the Philippines. It is available in huge rolls and sold by the metre. It is available in various thicknesses but I tend to go for around 20mm if possible. It is available with one or both sides covered in a metallic finish. This can be removed but a bit tricky.
I use clear mastic as an adhesive.
Once the piece of scenery is constructed I paint the exposed foam as soon as I can before too much rain gets to it. It is the monsoon season here but at the moment the rain is holding off. In the rain it can absorb water like a sponge. Painting the exposed edges reduces this problem. The material dries out fairly swiftly in the heat and sunshine.
I have used it for walls, with buttresses to provide strength. I have just completed a large bridge structure - looks a bit like Tower Bridge in London except that there are two levels and the bridges do not open. I have also made a signal box and roofed it with sheet metal.
Once constructed, and before painting, I use a soldering iron to score "bricks/stones" into the foam.
For paint I am using ordinary, oil based paint, including red oxide primer.
Here in the Philippines I am somewhat limited in the availability of suitable materials. So far I am pleased with this foam. However as I have only used this material for less than a year I have no experience of its longevity. Particularly bearing in mind the sun, heat and rain. But it's cheap enough to experiment. There is little strength to the material so either use: a frame; buttresses; thicker material; and form into towers (boxes). Be prepared, I suppose, for a shortish product life. But it's cheap enough to experiment.
Final point - it will not give the quality and appearance of a professionally made model such as those shown in an earlier post.
I hope this helps.
Cheers,
Tim
 
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Perry

Perry

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24 Nov 2017
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I used Celotex or Kingspan Polyisocyanurate PIR rigid insulation for a tunnel mouth. It's closed cell & easy to carve. I painted it with Sandtex masonry paint from a 50p sample tin. I considered using PIR for a viaduct & a bridge over the pond, but settled for timber. https://www.secondsandco.co.uk/

Polystyrene foam is inexpensive but too friable & would probably snap under the weight of snow.

Polyisocyanurate - Wikipedia

106785_a54f1b38c9631ef57c4fdfb8900a4303.jpg
 
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idlemarvel

idlemarvel

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13 Jul 2015
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...
Here’s a relevant video that appeared on my YouTube this morning...

Dan
That man has some talent and the patience of a saint. Towards the end I thought surely he's not going to apply individual slates but he did and not only that chipped the edges and applied three different coats of paint to get the right slate effect. Astonishing. A masterclass in modelling. Thanks for posting.
 
korm kormsen

korm kormsen

Registered
24 Oct 2009
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the hard(er) shelled softcore sheets are one of the very few materials, that i really dislike.
difficult to cut exactly, one wrong cut means throw away the whole piece, one cant splice together sheets for larger pieces, making corners is something for masterbuilders and embossing bricks seems impossible.

if i need material, that is less coarse than styropor, i buy foam plates or foam trays and splice them together.