TL;DR — The best wargaming bases in my opinion are Foamed PVC Signboard, true Hardboard (not HDF) or MDF that is appropriately primed on all faces, sides and edges to prevent warping.
See the ‘Deciding Factors’ at the end of this article for making decisions on when to use each.
Without delay after posting my first article, I asked my audience on Instagram what terrain questions they would like answered. Thereupon, a recurring theme came back; “What’s the best material for basing terrain?” With attention to ‘best’, I began to jot down the traits needed of a material for terrain. All things considered, I came up with the following:
- It must not add too much weight to the terrain piece
- Easy to cut, shape and carve with hand tools. Preferably manual but not discounting electrical hand tools
- Have rigidity to withstand handling and hold scenery structures at 5mm thickness
- Be resistant to warping when comes into contact with liquids and adhesives
- Will accept a variety of adhesives to attach other materials to it. This should include gypsum plaster, contact adhesive, PVA, cyanoacrylate (super glue) and 2-part epoxy resin
- Ease of applying paint
- Won’t break or shatter under impact
What do I need to know about warping?
Know this well; warping is the enemy of the terrain maker. It doesn’t barrage us with a blitzkrieg assault. No, instead warping is like an Inquisitor incursion slowly but effectively breaking down our defences. To begin with, we think we are on firm ground in our garrison under the protection of guards all around. Slowly, but surely those guards go missing. One-by-one they disappear and the façade of stability with them. In due time warping works its depraved assault, declaring us ‘heretic’ in one of two ways.
The first of these ways is when the baseboard material takes on the moisture content of water or adhesives. Penetration of liquids into the core material causes it to expand. Hygroscopy is the fancy scientific term for this attraction and retention of water. It in turn works in two ways; absorption or adsorption. Whilst absorption we know as how water permeates the surface, adsorption is infrequently used or familiar to us. In short it is the attraction and retention of water to the surface of the material creating a film of the adsorbate on the surface of the adsorbent. Although the latter does not cause warping, it is worthwhile knowing. We will cover why later in this article.
The second tactic of the inquisition is to warp the material with the inward pull of drying adhesives/materials placed on top of the base. Yes, that’s right; attaching itself like an ectoparasitic infestation of scabies that induces blistering and scales on the surface of its host. You see, certain types of glues and materials contract as they cure or dry. And this can be a problem. If the inward pull of the parasite is stronger than that of the base material it will lift the edges upwards causing a bow to form.
The terrain base candidates
Foamed PVC Signboard
Note: Not to be mistaken with closed-cell extruded polystyrene (XPS), also commonly known as blue foam or the trademark styrofoam. Likewise, not to be mistaken with PVC mountboard.
At the present time foamed PVC signboard is my main go to material. It covers pretty well all of the factors previously listed. Notably, its resistance to warping. To demonstrate, I can slap a whole load of modelling compound straight onto a boards surface without fear of movement; this is a product containing gypsum plaster, cellulose fibres and water. Once dried, I brush PVA glue on top of the dried compound and any gaps protruding through to the board. I then sprinkle on some basing materials such as sand, grit and tiling grout. So far so good? But things are now about to get a whole lot wetter. To break up surface tension before spraying with a PVA basing solution, I soak with a mist of isopropanol alcohol. It is now time to step away and leave to dry.
In this example I have used a whole host of liquids. Conclusively, I am happy that PVC signboard is not absorbent. It is however adsorbent, attracting moisture to its surface. The only consideration when using this is to make sure the surface is covered. In my mind, adsorption is a non-issue when we will be covering it with ground covers, adhesives and paints.
On the negative side, foamed PVC signboard cannot be shaped as easily as say MDF.
Medium-Density Fibreboard (MDF)
This manmade sheet board material is an engineered wood composite that combines wood fibres with a wax and resin binder. It is a particularly thirsty material, soaking up water and other liquids like a sponge. Sealing it on all sides and edges is a must to prevent it from swelling like a pimple on a poxwalker. But before you go reaching for the faithful aerosol rattle-can that we prime our plastic miniatures with, think again. Instead you will need to make use of an oil or alcohol based primer. Something like Rustins Primer and Undercoat or Zinsser B.I.N Primer and Sealer. Seal all sides and edges with two thin coats (especially for you, Duncan) before attempting to adhere any basing materials on top.
When to use MDF for basing terrain
When then would I make use of this material? Firstly, be under no illusion about the weight of MDF. It is a very heavy sheet material due to being jam-packed full of highly compressed wood fibres. Consequently, it is an extremely robust and hardy material, making it ideal for heavy use situations. Use MDF when you’re making terrain for a local club that will be used weekly by many gamers. Ideally, the club will have on site storage too, negating the need for servo-haulers to transport it all.
Another occurrence I would use MDF is when basing a heavy resin structure. By and large we do not want a baseboard to flex under the weight of this structure when picked up. For rigidity under stress, I choose MDF.
Lastly, I use MDF when not only do I require robustness, yet also there is a necessity for the shape and edges to be smooth with perfect contouring. I can’t get this with Foamed PVC Signboard as I previously stated. Therefore if I have a scatter terrain piece with a rocky outcrop or grove of trees, I will want that contoured and blended in as closely as possible to the gaming mat. This is when MDF comes into its own with the fantastic quality of being consistent throughout with cut edges appearing smooth without voids or splinters.
High-Density Fibreboard (HDF)
The engineering of HDF board is similar to MDF. As you would expect though, HDF contains more wood fibre per cubic metre than MDF board. This makes it harder and stronger, yet it is a very different product to MDF. Apologies in advance, I have some dull numbers coming up. They do illustrate the density difference however, and will be useful when we learn about the next material. Whereas MDF has a typical density of 600-800 kg/m³, HDF is 900 kg/m³ within a very thin board typically between 3-8mm. It is commonly used in laminated floor products where this density is required, though other uses include cabinet backings, door skins and underlay. In short, it isn’t just a more compact higher grade of MDF.
The finish on HDF is smooth and will have a bit of a sheen to it when it catches the light. Don’t be fooled by this though, it is still a porous material that will absorb water. So as with MDF, you still need to seal the HDF board on all sides and edges to help prevent warping. Unlike MDF though, it is not easy to work with tools to graduate the edges. For this reason, I stay clear of HDF in favour of Foamed PVC Signboard, a lighter material more resistant to warping.
Now I know some of you are going to say hardboard is HDF by another name. As a matter of fact, HDF is commonly and incorrectly referred to as hardboard. The true hardboard I refer to is very different from HDF. How so? Well, it is yet another manufactured board, I will give you that. Nevertheless, let’s look deeper. The manufacturing process is one of the most significant differences between hardboard and MDF or HDF boards. In this case, MDF and HDF boards use a dry process method and use synthetic binders or formaldehyde based agents for binding the wood fibres. In contrast, hardboard uses a wet/dry process method that relies on the natural binders within the wood to cement the fibres together and make the wood solid. Ampersand, who manufacture a type of hardboard explain why this is significant
The wet/dry process used to manufacture hardboard
“The wet/dry process used to manufacture Hardboard has several advantages. The wet process method produces a smooth-one-side (S1S) panel, while the wet-dry process produces a smooth-two-side panel (S2S). Both processes explode the wood particles using steam pressure, and float them in a large vat of water, which pulls out many of the naturally acidic agents within the wood. The wood fibers are then randomly aligned parallel to the surface, and using heat and pressure, are made into a solid core panel. […]”
“This process allows a very uniform and very strong panel, making it one of the best substrates for painting, laminating, and construction. While still a relatively light-weight panel, Hardboard has a significantly higher density compared to MDF panels with a much higher tensile strength and internal bond than MDF and most HDF panels.”Painting on Panel: The differences between HDF and MDF | Ampersand | June 6, 2013
From here we are briefly back to the numbers. This is significant, remember that both MDF and HDF are in the realms of 600-900 kg/m³. Well, hardboard is nearly double that at 1,450 kg/m³. Lots of hardboard manufacturers will temper the hardboard too with linseed oil, making the board hugely moisture resistant and much, much less prone to warping than both MDF and HDF. For these reasons, hardboard is a commonly used canvas for artists using acrylic and oil colour paints.
Hardboard is a specialist artist grade material, and as a result will carry a premium cost. If you absolutely must have a thin 3mm board that won’t flex like foamed PVC signboard (probably because it is a large scatter terrain piece) then this is your best bet. In any event, a single 11 x 14′ sheet of Ampersand ‘Hardbord’ brand will set you back £12.00 at RRP.
Plywood is certainly another option available from the manmade wooden board family. Thin layers of wood veneer called “plies” makeup the structure and give the board its name. Adjacent layers adhere with their wood grain rotated up to 90 degrees to one another. Consequently, this provides a host of strength and stability gains to the wood. Most importantly for us as terrain builders, it reduces expansion and shrinkage that could mess up our ground covers. Notably too, most plywood is produced with an uneven number of plies to balance the board and reduce warping. Comparatively, plywood is stronger than MDF even though it is lighter. You pay a premium for this extra strength. Despite this, plywood still works best under conditions of little to no moisture. A board will need to be sealed adequately to prevent issues with all those liquids and adhesives we use to create terrain.
The Deciding Factors
I want to squarely base a terrain form or structure cheaply.
Choose Foamed PVC Signboard. You can pickup offcuts and scraps from sign makers at no cost or obtain brands such as Foamex and Foamulux sheets at reasonable costs.
I am basing something that needs to have rigidity and won’t flex under the weight of the structure I put on top of it.
Choose MDF or true Hardboard, such as the ‘Hardbord’ brand from Ampersand. Be sure to prime MDF board on all faces, sides and edges to prevent warping.
I need to be able to shape and blend my base in with smooth contours to my gaming table.
Choose a quality MDF board that can be cut and sanded by hand. Once the board has been worked to your liking, prime on all faces, sides and edges to prevent warping.
For me, the strength to weight ratio is the most important factor. It must be strong. It must be lightweight.
Choose between either Foamed PVC Signboard or true Hardboard.
Enjoyed what you read?
I hope I have entertained you and perhaps taught you a few things along the way. If you enjoyed what you read, please take a moment to share using the buttons below and subscribe to my newsletter.