Question. Expanaded PVC board. Can you cut it with a craft knife?

[olicana]

I've heard people are using this stuff to make model buildings, etc.

Is it easy to cut up. Can you cut it with a heavy duty craft knife / Stanley knife?

I'm wondering if to order this instead of 5mm card and foam board to make more flat topped 'desert style' buildings with parapets. It sounds pretty durable.

[Emir of Askaristan]

Expanded Polystyrene is the stuff that breaks down into balls/beads. You can cut it with a craft knife/stanley/etc but doing so usually breaks it up, even the really dense stuff and leaves some kind of rough uneven edge...and a lot of small white polystrene bits sticking to anything and everything, this is likely to result in what is known as a "thick ear" if done inside the house...

A polystyrene cutter does a better, smoother job - but should be done in a well ventilated place (see thick ear above).

Extruded polystyrene is the blue/pink densely packed material which doesn't break up into little balls. It's much neater and more easily shaped and sculped. It can readily be cut with a knife, sanded, etc. It has the added benefit of being less likely to result in the aforementioned domestic injury, although this is still not unknown.

Foamcore is some extruded polystyrene sandwiched between two thin layers of card. It cuts easily, is usually about 5mm thick and is great for walls, buildings and other constructions.  I think this is what you're after!

Cut safely now!
Askaristan Safety Dept

[Mindenbrush]

This is the material that looks like foamcore but has a denser foam sandwiched between pvc covering rather than paper.
Also called “foamex” I believe.
I used a scalpel to cut mine.

[BZ]

I use 3mm thick boards of it, and its easy to cut (2-3 strokes) with craft knife.

[AndrewBeasley]

Have a look at


Not the best example of safety but shows you the different foam types being cut with a carving knife and 'Stanley' knife.

[CookAndrewB]

I love PVC board. Yes, it cuts fine with a craft knife. I use a mix of 5mm and 1mm and the 5mm takes a couple of passes while 1mm cuts easily in a single pass.  Not only does it cut well, but it etches well, and I've had good success with both PVA and super glue bonding it to other items. Here is a project where I was using 5mm PVC board to make sci-fi consoles for a 15mm spaceship.



And the finished product:


I also use this material for basing larger terrain items (it can be textured by rolling a foil ball around on it) and I've even used it to carve bodies for 6mm mecha (far right)


It is useful material. I'd buy this every day over foam core or other foam products.

[olicana]

that latter stuff looks like it. Thanks. Its the first time I've come across it and it looks like it would have a better edge finish than foam board (card sided) that I've used up to now. Not that card sided foam board does a bad job.

[CookAndrewB]

PVC board has less warping than foam core, though I'm not sure anything is entirely impervious to it. I'm convinced I could warp 1" sheet steel with the right application of PVA.

I have found that foam core is less likely to warp if the paper is removed first.

[Wirelizard]

Foamed PVC board (Sintra is one of the common brand names) is brilliant for buildings and scenery bases and such. It cuts easily with a sharp knife, just use a steel ruler and take a few passes to get a clean edge. Unlike foamcore or card it can filed and sanded, if you want rounded edges or need to clean up an edge that didn't cut clean.

My local plastics/signmaking shop used to have loads of the stuff cheap in their offcuts bin but have been using less and less of it the last few years; last time I went in I just wound up buying a new 2x3 chunk from them because there was none in their offcut bin. (they're using more vinyl fabric and corrugated plastic for signs, apparently, as they're both cheaper than PVC board...)

[carlos marighela]

…..and then there’s Corflute, which is made from a polypropylene resin. Commonly used for advertising and election signs. It’s essentially two flat sheets divided by perpendicular dividers, so seen from the side, a hollow shape, a bit like the interior of a breeze block.

Advantages: Cuts quite easily, is lightweight and yet quite rigid and strong. Not difficult to find offcuts, so potentially very cheap. The gap between the internal dividers appears as a very, slight corrugation so useful for making rendered brick or breeze block walls. The square holes at each end are also useful for connecting up lengths, using any handy bit of sprue, balsa etc inserted into the holes at each end. Smooth surface but can be rendered using most of the usual methods. Roughly cut it’s a really good stiffener for the insides or backs of card buildings.

Disadvantages. The internal dividers mean you have to carefully plan your cuts and they are best made just above the divider. Blades dull very quickly cutting this stuff but that’s true of foam core and other materials.

It has its uses.