Warping Terrain Tiles

[Ssendam]

Hi all ... a little practical advice please ...

I'm building a set of terrain tiles (to represent the pavement streets of 70/80's) and was busy over the weekend doing a couple of test pieces ... and I was really please with the result. I'll publish results when I iron out he kinks.

For the test piece I :

- Used a square of 5mm Foam board 250mm x 250mm
- Glued two strips of 5mm Foam board 45mm x 250mm on either side of the square with wood glue.  I weighted this down to keep it flat while drying.
- I then painted the foam board with emulsion in Grey (house paint ... for walls).
- I let it dry a bit and weighted it down.

I did a few other bits relevant to modelling but not to my problem.

So the shock is that the board warped.  I should have expected this, and I think it's the emulsion that is the main culprit.

Sooo... a few questions:

The base ... I think that the foam board is never going to cut the mustard for this.  I'm thinking of using 5mm (actually I think you can only get 6.5mm) plywood. I only need 25 squares of 250mm x 250mm.  Do you think I'm going to get warping with the Plywood of that thickness? (when it's painted and if I glue stuff to it).

Glue: I like wood glue, but it has a lot of moisture in it.  Would a contact adhesive or just a Pritt Stick be better?

Thought's?

[Dewbakuk]

5mm ply should be fine. PVA or wood glue will both be fine for attaching things, just don't do it too thickly. I wouldn't use foamboard for the base but if you did want to recover your test piece, pva gluing some newspaper to the back will probably pull it flat again.

[jmilesr01]

I use 1/4 inch plywood  (6mm) framed by 1x2 dimensional stock lumber and have never had any warping.



In the picture there's a center brace which is really only needed if there is something heavy going on top like a big bill of resin to simulate water.

If you don't want to do all the wood cutting or the height then I would suggest using floor tiles as your base - they tend not to warp

[Ssendam]

Framing the tiles is not really an option as they are only small 250mm x 250mm, and need to all fit together ... but it's good to see what you use.  You think unframed 6mm is solid enough?

[Major_Gilbear]

Use something like 9mm MDF. This is usually sold in 4'x8' sheets (1200mm x 2400mm), and you can have it cut into 1' (300mm) squares easily enough in most places that sell it.

As long as you're not absolutely soaking the pieces in water paint/glue, they won't warp.

I use 12mm for my boards because they are 2' x 4', and can otherwise bow a little along their length (as much from upright storage as from painting!)...

For small square tiles though, 9mm unframed is plenty.

[Silent Invader]

Framing the tiles is not really an option as they are only small 250mm x 250mm, and need to all fit together ... but it's good to see what you use.  You think unframed 6mm is solid enough?

I also use 6mm MDF but at 30 cm sq.  Some projects have the MDF framed and others don't .... Framing also enables sunken areas - rivers, basements, etc- to be cut into the tile.

[Elk101]

I've found 6mm mdf fine for my 300 X 300mm and 600x 300mm tiles,  but where I've used resin water or filler for roads and rivers the tile has warped
 I keep meaning to paint the other side to try and pull it back a little.

[mxconnell]

Hi,

Some thoughts:
Did you cover both sides with the emulsion on both sides of the tile? Painting one side guarantees warping. I paint both sides but only one half at a time so I have a place to hold the foam board. Always paint the same area on both sides at the same time.

Also recommend a non-water based glue, or at least a low water content glue. The paper terrain folks at World Works recommend  UHU Office Pen No.99589 as a low water glue to minimize warp of paper models. I use the UHU, spray adhesive, and Liquid Nails. The spray adhesive can be touchy as some brands eat foam.

Some craft stores offer glues specifically designed for foam - I have not experimented with these yet so I have no advice to offer there.

Best of luck,
Martin

[Melnibonean]

Don't use wood glue. Instead use caulk.
It doesn't shrink as it doesn't dry, as such. It cures and wont warp your boards.

[Atheling]

I use 1/4 inch plywood  (6mm) framed by 1x2 dimensional stock lumber and have never had any warping.



In the picture there's a center brace which is really only needed if there is something heavy going on top like a big bill of resin to simulate water.

If you don't want to do all the wood cutting or the height then I would suggest using floor tiles as your base - they tend not to warp

Yep, that's the way to go- build a frame and then put the tiles within that frame- or at least glue them to MDF (less warping than plywood).

Darrell.

[Ssendam]

Thanks for all the thoughts ...

I'm going to pioneer something a bit different (at least I've never tried it).  I'm going to get some off cuts of that aluminium backed sign board. It's about 5mm in thickness and might be the job.  As I'm using small squares I can make use of offcuts so I think I can get them cheap (I don't think they are that expensive anyway) and they are laser cut so perfectly sized.

I'll report back ...

[Ssendam]

So ... it's looks pretty solid stuff.  Only £2.50 for a slice cut exactly 300mm x 300mm.

[Silent Invader]

Good luck    Experimenting is a lot of fun.

One thing perhaps to still bear in mind is that warping can be due to one (or both) of two effects: contraction interior to the core panel and contraction exterior to the core panel.

For example, if I'm using a lot of 'wet' decoration, I usually first spray the MDF panel with a light coat of solvent based varnish, which will help prevent the MDF soaking up water.  However, this is no guarantee against warping as if I then throw on say a lot of superglue and sand, there'll be contraction between the glue and the sand that will induce warping from the topside.  That said, if I later bend the tile over a table edge (not so much as to snap the MDF) then fine cracks will be created within the decoration which, just maybe, will release the pull so as to flatten the warp.

[jmilesr01]

I'm interested in seeing how the aluminum backed sign board works - that's a very creative idea

Good luck

[Dewbakuk]

So ... it's looks pretty solid stuff.  Only £2.50 for a slice cut exactly 300mm x 300mm.

Local source or off the web?