Foam/Polystyrene for building up embankments

AlanG

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Title says it all really. What type of foam/polystyrene do i need for building up embankments/raised areas on a diorama base? I know the polystyrene you get with electrical appliances is no good because i creates those really annoying balls. Yes i could seal it in with a hot knife cutter but it's a hassle if i'm honest. Also where do you buy your foam from?
 

Gern

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That polystyrene with the little balls is good for rough stone work and rubble. For something smoother try insulation foam.

A quick check on ebay found this, but as always it's worth shopping around. I got mine some years ago from a company prepared to supply mixed thicknesses but I can't remember which company - sorry!

 

spanner570

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I always use the polystyrene packing from electrical appliances for building up ground and river banks.

Don't dismiss the stuff Al'. At least give it a try.... :thumb2:

Happy dioramarerering!

Ron
 

Jakko

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I know the polystyrene you get with electrical appliances is no good because i creates those really annoying balls.
The trick is to cut this type of foam with a sharp kitchen knife, something like a thin one used for cutting meat, and use long but careful back-and-forth strokes. Done right, you’ll cut the little foam balls in half instead of pushing them out of the material, which is what makes the mess. Yes, there will still be some lying about, but nowhere near as much as when you go hacking at the material with a bread knife (which is what Games Workshop used to recommend … :rolling:).

A more expensive alternative is a tool used for laying underfloor heating:

UNADJUSTEDNONRAW_thumb_367.jpg

This is one I used ages ago, borrowed from my next-door neighbour when he was putting such heating into his home, and I think he had it on loan or rent from the company where he had bought the necessary materials. Anyway, it’s basically a heated knife that will cut through polystyrene foam very well and leave no mess at all.

There are also tools that look a bit like a jigsaw but with a heated thin wire, which also work very well but you need to be careful you don’t snap the wire. I have one my father built for me almost forty years ago from a block of wood, two bicycle spokes, and a 12 volt transformer :smiling3: Apparently, you can make one from a 9 volt battery.

Also where do you buy your foam from?
DIY stores. Plates 50 × 100 cm in size are available in all kinds of thicknesses, and cost very little.
 
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The cheap bobbly stuff is expanded polystyrene (EPS). The smoother, insulation type is extruded polystyrene (XPS). That might help in your search :smiling3:
 

AlanG

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Cheers guys. I do have some of the 'normal' polystyrene from a washing machine we've just replaced but i thought it was useless because of the balls and the really odd shapes it is moulded in
 

spanner570

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Al', you don't need 'posh' cutters etc. Use a junior hacksaw blade out of it's frame.

You don't need to aim for a smooth finish either. As most of the building up will be for terrain work, the rougher the better.

Make sure you have plenty of those balls showing in your cuts. They make superb ready made rocks and boulders. No need to faff about adding spready stuff!

To make it even rougher, hack at it with your finger nails. Always be careful of the nail varnish!
 

AlanG

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Always be careful of the nail varnish!

More worried about the pig muck under my nails if i'm honest lol.

Cheers Ron. This will probably be my first ever diorama as the other one i have planned (a rather big but eye-catching dio) has hit a slight brick wall as i've lost part of the build somewhere and it's an important bit. I suppose i'm just so used to seeing guys with nice smooth polystyrene i've become blinded that i can actually use 'normal (EPS)' polystyrene. It will all be covered in the end as it'll be grass and small rocks/stones on top.
 

BattleshipBob

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Good question Al, never even attempted one, so good on you sir!!
 

AlanG

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Cheers Bob. This will be an 'easier' build than the other one planned even though it has more detail. But i'm not an accomplished modeller so everything is a challenge lol
 

rtfoe

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Hi Alan,

I use an NTCutter blade like the one in the picture attached. Put in a new blade, extend it out more than half its length and cut with a slicing motion, don't push. You can even try a sawing motion and it cuts very smooth.

CAT0014.jpg

77.jpg I cut these buildings using the same cutter from the same type of polysterene with the balls.

And below same material and sliced with the same cutter...no sanding required. It's a matter of how you control the strokes and angle of the blade. Never use old blades.

365198.jpg

Cheers,
Richard
 

Si Benson

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I do smile when you guys talk about polystyrene with the balls:smiling5:

A bit off topic, but I work for one of the UK’s biggest EPS (polystyrene with balls) manufactures and have done for over 25yrs as a process technician, tool fitter, supervisor, mechanic and fault finder!

The stuff with balls is known as EPS, expanded polystyrene. I could bore you all to death with the ins and outs but I’ll spare you that:smiling5:
 

AlanG

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Cheers for all the advice guys. Just ordered some balsa wood for the diorama so i'm starting to get all the kit together for it. I'll give the EPS stuff a go at first and see if i can get on with it.
 

Tim Marlow

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Loads of hot wire cutters on amazon, all shapes and types....I think I’d just cut it with a sharp knife and hoover up afterwards though :cool:
 

minitnkr

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Been using EPS for years as it is free w/most pkgd things you buy. Never paid much attention to how to cut it as I use it for base forms. I seal it w/left-over water based house paint & cover it w/PVA'd ground cover, scale rip-rap, cinders and/or drywall taping compound. This allows for carved masonry or rock faces. PaulE
 

JR

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Well I think I should join in as well .

570 does an amazing job with his creations from Polystyrene, especially for his bases. but I tend to use foam board for buildings. The peelable surface is easily removed if you have purchased KAPPA LINE and extremely easy to work with. Cheaper makes can prove to be harder to remove, the best method is using a hair dryer set on a low heat.

If anyone is interested there are some great help sheets by David Neat at the 4D Model Shop.

http://modelshop.co.uk/Static/Model-Making-Guides.

The shop is a gold mine for anyone interested in materials, but they don't sell model kits!
Of course I have no connection with either David Neat or the 4D Model Shop, but have made a few purchases from the shop and always been satisfied. :smiling2: .
 

rtfoe

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Hi Al, I should have paid more attention to your title.

For the embankments I use compressed foam boards. These are foam sandwiched by two pieces of card and can be bought at artshops. Stationery shops in Malaysia stock these as well. Before using this material I would have used cereal box card to shore up the sides and before that plaster and sanding flat. I have settled with compressed foam boards as they are easy to slice to fit the contours of the dio base surface.

Some modellers would use single ply ply-wood or balsa for that all wood look after staining. The Japanese would go further and lacquer their wood to a mirror finish like their Bento boxes.

My last picture earlier has the edges lined with the compressed boards.

Cheers,
Richard
 
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