Styrofoam Buildings

[Monifieth Stuart]

After watching some YouTube videos on buildings using styrofoam, I was experimenting with railway creations mainly viaduct premises with shops etc built in. Some polystyrene strips ( to represent wood planking etc) have been integrated as well and I use acrylic paints. and PVC glue. So far so good. However, the videos are mainly indoor wargamers so how do I waterproof my outdoor buildings. I have already found that some glues and spray paints simply melt the styrofoam so I am wary of just spraying with any varnish or sealer just in case... Your advice please. Stuart

 

[dunnyrail]

After watching some YouTube videos on buildings using styrofoam, I was experimenting with railway creations mainly viaduct premises with shops etc built in. Some polystyrene strips ( to represent wood planking etc) have been integrated as well and I use acrylic paints. and PVC glue. So far so good. However, the videos are mainly indoor wargamers so how do I waterproof my outdoor buildings. I have already found that some glues and spray paints simply melt the styrofoam so I am wary of just spraying with any varnish or sealer just in case... Your advice please. Stuart

I have used Halfords Car Undercoat sprays, these work pretty well and are long lasting. Red (bauxite brown), black, grey, white and yellow available. Also tube acrylics last very well, I got some 20+ years out of Rowney tube gray.

 

[Monifieth Stuart]

I have used Halfords Car Undercoat sprays, these work pretty well and are long lasting. Red (bauxite brown), black, grey, white and yellow available. Also tube acrylics last very well, I got some 20+ years out of Rowney tube gray.

I have used Halfords spray on polystyrene and foamboard but not on styrofoam. Similarly it is the sealer coat to keep out water that I am concerned about now.

 

[dunnyrail]

I have used Halfords spray on polystyrene and foamboard but not on styrofoam. Similarly it is the sealer coat to keep out water that I am concerned about now.

Well I have used it on styrofoam and it works just fine. Not sure why you need to worry about keeping out water? But as it is used primarily for cars it should be fine, but unlikely so in a boat situation where a covering with marine varnish would be what you need. So undercoat, varnish more undercoat then finish colour?

 

[Monifieth Stuart]

Well I have used it on styrofoam and it works just fine. Not sure why you need to worry about keeping out water? But as it is used primarily for cars it should be fine, but unlikely so in a boat situation where a covering with marine varnish would be what you need. So undercoat, varnish more undercoat then finish colour?

Ah the penny has dropped. I did not risk using Halfords primer on styrofoam first then painting over with acrylics in case the foam melted as it does with some spray paints. Once you have finished with the painting, what would you spray the whole thing with? According to google searches even dense styrofoam will absorb water because it is so porous. Then I would expect the frost to do the real damage outside. Stuart

 

[dunnyrail]

Ah the penny has dropped. I did not risk using Halfords primer on styrofoam first then painting over with acrylics in case the foam melted as it does with some spray paints. Once you have finished with the painting, what would you spray the whole thing with? According to google searches even dense styrofoam will absorb water because it is so porous. Then I would expect the frost to do the real damage outside. Stuart

Right it does not melt with Acrylics, I have used it outside for buildings (as have many others on the forum) and it does not suffer from frost damp effect. I expect this is because the foam is very dense and does not get soaked inside. Have a look at Ge_rik and David1226 who both also extensively use Foam Coated Plastic Board. In fact I got a lot of my inspiration to use the stuff from their postings.

 

[Monifieth Stuart]

Right it does not melt with Acrylics, I have used it outside for buildings (as have many others on the forum) and it does not suffer from frost damp effect. I expect this is because the foam is very dense and does not get soaked inside. Have a look at Ge_rik and David1226 who both also extensively use Foam Coated Plastic Board. In fact I got a lot of my inspiration to use the stuff from their postings.

Here is where I get confused again. I have used Foam Coated Plastic Board for loco shed. A few mm thick but can be scored with screwdriver etc to make brickwork. I have pinched ideas from Mike on his use of Foamex. Then there is polystyrene which is thin plastic sheets, strips etc as sold by Evergreen etc. It is a hard plastic but special glues melt it together. Both I have tried and used Halfords Primer, acrylic paints, clear sealer spray etc with no problems. Now I am on to styrofoam which is dense, dark grey (used to be blue I believe) and comes in 20 or 30mm sheets or blocks. This is what melts if I you use many glues and aerosol paints on it. It is quite a soft material so cuts with sharp knife or hot wire cutter. Have I got this correct? If so, your post above is reassuring re frost damage etc though I guess the acrylic paint would need some sealer as it is water based. thanks for your patience. Stuart

 

[dunnyrail]

Here is where I get confused again. I have used Foam Coated Plastic Board for loco shed. A few mm thick but can be scored with screwdriver etc to make brickwork. I have pinched ideas from Mike on his use of Foamex. Then there is polystyrene which is thin plastic sheets, strips etc as sold by Evergreen etc. It is a hard plastic but special glues melt it together. Both I have tried and used Halfords Primer, acrylic paints, clear sealer spray etc with no problems. Now I am on to styrofoam which is dense, dark grey (used to be blue I believe) and comes in 20 or 30mm sheets or blocks. This is what melts if I you use many glues and aerosol paints on it. It is quite a soft material so cuts with sharp knife or hot wire cutter. Have I got this correct? If so, your post above is reassuring re frost damage etc though I guess the acrylic paint would need some sealer as it is water based. thanks for your patience. Stuart

Ah Styrofoam, tis me that was confused.

Ok I have used a similar substance that is used for wall and Insulation for a mountain in my garden. I was warned of the unsuitability of this for the purpose but it worked just fine. You could use a sealer though not really necessary, but what are you going to use it for perhaps should have been an earlier question. Out of interest where have you sourced it from? I have wanted to use some for scenic purposes on a smaller gauge railway?

Builders SBR Bond or external grade PVA will seal it nicely.

 

[Monifieth Stuart]

Ah Styrofoam, tis me that was confused.

Ok I have used a similar substance that is used for wall and Insulation for a mountain in my garden. I was warned of the unsuitability of this for the purpose but it worked just fine. You could use a sealer though not really necessary, but what are you going to use it for perhaps should have been an earlier question. Out of interest where have you sourced it from? I have wanted to use some for scenic purposes on a smaller gauge railway?

Builders SBR Bond or external grade PVA will seal it nicely.

This is available on Amazon for craft use. Oddly I was told that there was a cheaper builder's version but when I bought a sheet of insulation from Wickes it would not cut on the hot cutter. This is the stuff used by modellers on YouTube such as

. I think they are impressive though they insist on adding tanks or dragons to their scenes. And obviously they are the wrong scale (1:36 instead of 1:24). I have been trying to create a series of railway viaducts to add to a ramp (see below). I will try PVA to seal the paint. Thanks. Stuart

 

[dunnyrail]

View attachment 294858 This is available on Amazon for craft use. Oddly I was told that there was a cheaper builder's version but when I bought a sheet of insulation from Wickes it would not cut on the hot cutter. This is the stuff used by modellers on YouTube such as

. I think they are impressive though they insist on adding tanks or dragons to their scenes. And obviously they are the wrong scale (1:36 instead of 1:24). I have been trying to create a series of railway viaducts to add to a ramp (see below). I will try PVA to seal the paint. Thanks. Stuart

High again Stuart. The denser Foam appears to be more readily available in the States but only via penny amounts in UK. I am pretty sure that it will be fine unsealed outside in uk. But why not make say a small line side hut or railway type phone box to see without busting the bank?

 

[JimmyB]

Picked up from Wilipedia

Styrofoam is a trademarked brand of closed-cell extruded polystyrene foam (XPS), commonly called "Blue Board", manufactured as foam continuous building insulation board used in walls, roofs, and foundations as thermal insulation and water barrier. This material is light blue in color and is owned and manufactured by The Dow Chemical Company. Dow also has produced a line of green and white foam shapes for use in crafts and floral arrangements.

Styrofoam is colloquially used worldwide to refer to another material that is usually white in color and made of expanded (not extruded) polystyrene foam (EPS). It is often used in food containers, coffee cups, and as cushioning material in packaging. The trademarked term is used generically although it is a different material from the extruded polystyrene used for Styrofoam insulation.

Additionally, it is moderately soluble in many organic solvents, cyanoacrylate, and the propellants and solvents of spray paint.

I have used/use XPS for many purposes mainly insulation, but never model making, though I have seen it used in smaller gauge landscapes. I have just tested a piece of my black XPS with Humbrol thinners, and it melts, so it would seem this is an inherent problem with XPS.

 

[SevenOfDiamonds]

I have used 10mm (blue) styrofoam for buildings but only used them indoors (exhibition layout) so far. I scribe a brick pattern, overpaint the entire undulting surface in dirty cream household emulsion (to represent the mortar) then sponge onto the higher surface either acrylic paints, or exterior masonry paint (readily available in a terracotta shade).


In the "great outdoors" I have used the same 10mm material to build a set of steps (between sidewalls made of ceramic tiles). There I just coated the visible surfaces of the styrofoam with grey acrylic paint and left the unseen parts unpainted. No deterioration so far . . . but with a minimal level of detailing, I didn't worry too much. Once you've spent hours scribing brickwork, it would be a disaster if it did deteriorate. A small test piece, as suggested above, would be how i would proceed!

Best wishes

David

 

[Monifieth Stuart]

I have used 10mm (blue) styrofoam for buildings but only used them indoors (exhibition layout) so far. I scribe a brick pattern, overpaint the entire undulting surface in dirty cream household emulsion (to represent the mortar) then sponge onto the higher surface either acrylic paints, or exterior masonry paint (readily available in a terracotta shade).


In the "great outdoors" I have used the same 10mm material to build a set of steps (between sidewalls made of ceramic tiles). There I just coated the visible surfaces of the styrofoam with grey acrylic paint and left the unseen parts unpainted. No deterioration so far . . . but with a minimal level of detailing, I didn't worry too much. Once you've spent hours scribing brickwork, it would be a disaster if it did deteriorate. A small test piece, as suggested above, would be how i would proceed!

Best wishes

David

That looks promising if yours has survived so far outside. I began to imagine the rain soaking in and then the frost smashing it apart in the worst case scenario. I think I will just have to try it outside in the spring. The railway viaducts will be at the back of the layout so as long as it does not collapse, it should be ok. Thanks for all advice again. Stuart

 

[GAP]

I have used the EPS poly styrene foam on my railway platform, I coated in acrylic house render coloured with a grey oxide and it has been outside in the Australian climate for over 12 months with no sign of deterioration.
It glues quite well with exterior PVA woodworking glue.

The EPS is sourced from electrical retailers who are more than glad for me to take it as they do not have to pay for dumping it.

I plan to build some more buildings using the method.
Similar to this Construction of a small lineside building

Another product I have used previously is "Hebel".
Similar to this Sandstone & Termite Garden Railway-Using Hebel

 

[Monifieth Stuart]

I have used the EPS poly styrene foam on my railway platform, I coated in acrylic house render coloured with a grey oxide and it has been outside in the Australian climate for over 12 months with no sign of deterioration.
It glues quite well with exterior PVA woodworking glue.

The EPS is sourced from electrical retailers who are more than glad for me to take it as they do not have to pay for dumping it.

I plan to build some more buildings using the method.
Similar to this Construction of a small lineside building

Another product I have used previously is "Hebel".
Similar to this Sandstone & Termite Garden Railway-Using Hebel

I have used these 'hebel' type of bricks but just sawed for supports. I don't know if I would have patience for bridge building. Stuart

 

[dunnyrail]

I have used these 'hebel' type of bricks but just sawed for supports. I don't know if I would have patience for bridge building. Stuart

one of the uk trade names is Celcon. There are other varieties, back when I was in Hemel I found a White variety that came in much longer sizes and would be perfect for viaducts. I have a small viaduct on my line from Celcons cut out using a jigsaw. Just cut one side then do the other letting the blade follow the first cut. Simples but wear a mask and do it outside.

 

[Monifieth Stuart]

Thanks for advice about metal wheels. Completely unrelated topic, I have used styrofoam from the Bluefoam company (in Ireland?) for modelling previously. Have they gone defunct recently?