This is a placeholder for ideas about making a bunch of cheap whiteboards for our hack space robots and dinosaurs. We'll post more when it's finished.

Our aim is to cover any surface with whiteboard material, to make a kind of leak-proof-room from which ideas cannot escape.

Some sites which served as inspiration:

http://chrismetcalf.net/blog/archives/2007/06/16/how-to-dirt-cheap-wall-sized-whiteboards/
http://www.kk.org/cooltools/archives/000679.php
http://www.kickerstudio.com/blog/2008/10/diy-whiteboard-for-under-50/

I went to the hardware store to see what was available. The attendant had never heard of the "shower board" or "tile board" the other websites mentioned, and only knew of shower boards that started at ~$200 per sheet, so I wandered the isles having a look at anything vaguely whiteboard-ish. Some contenders for the mystery title of "showerboard" were:

• Melamine board. This is about 3mm thick and very cheap. A 1200x900 sheet is $9.98.  According to Wikipedia, Melamine is the original whiteboard material, but I didn't know that at the time.
  
• "White board" This was particleboard with Melamine sheeting applied to it. It appears to be mostly used for shelving and was difficult to get in wide enough sizes for our usage.
• Masonite didn't look like it had the right finish, but it was hard to tell.
• "HandiBoard" was a white polypropalene, in thin sheet form and the label mentioned it was suitable for whiteboard applications. However it was more expensive and the pieces in the store were quite warped. 1200x600x3 sheets were ~$41 ea.
• A notable mention was the concept of black-board paint. This was pretty cheap, about $17 for a small tin. However reading the fine print indicated it was intended for "most smooth timer surfaces". If we want to use this, we'll have to put up wood first.
  

I also saw some solid looking doors for just under $30. If we end up gluing to a hard backing, I'll probably use those. They're strong and cheap and the sides should be suitable for putting in pivots and making a tilting stand. Dimensions 2040 x 820 x 35.

I still wasn't sure what material to get. I was considering going back and doing more research on the net to find appropriate materials. After walking up and down the isles for a ages, I realised I was being silly and just bought a medium piece (900x600) of melamine to try out. It cost $4.95.

Stacking up against the competition:

On the way back from the hardware store, I went to 3 second hand office furniture stores, which were all huddled together in the same street, like women using the bathroom together.

The best price I could find for whiteboards was a 900x1200 board for $134 for wall-mount and $300-500 for a mobile version.

Road-Test:

After getting the melamine sheeting home, I did a couple of drawings to test it out. The results are here:
The main problem was that, although the ink was laid down nicely on the surface, it dried and shriveled up about ten seconds later.
Remember the scene where the Nazi withers away in Last Crusade? Now imagine that happening to all the ideas you want to share with others.

I noticed that the texture of the ink I could lay down was not constant across the board, and there seemed to be a good 'stripe' of real estate running vertically, just left of the middle. I figure this has to do with the coating which was applied to the board, and that in the hardware store the boards have been scraping across the top of each other in the stack.

On the plus side, there was no problems with erasabilitly. Everything seemed to come off nicely.

So, to try and improve matters, I used some fine P240 sandpaper and made a few test patches to see the difference. Only very light sanding was used, even so it still discoloured a little. I also gave the board a clean with acetone (a.k.a. nail polish remover). This cleared it up nicely. However, when I compared the half of the board which was sanded, to the half which wasn't, there wasn't a huge difference. Probably the cleaning with acetone was the most significant part. There are still a few bad patches, but more cleaning and sanding should sort them out. See the results here:

Update: Don't sand Melamine after all!

Although everything erased well the first time, the next day when I went to erase the sanded side of the test patch, it didn't come off well at all. Removal with acetone is possible, but it reduces the usability of the board to require solvent for every erasure.

To summarize, only use a small amount of acetone cleaning on the brand new Melamine surface, and don't sand. This should be enough to get the surface to accept ink without beading, and give you a nice whiteboard finish.