What wood should I use to make an outdoor blackboard?

[carlyla]

I have an A frame blackboard made from exterior grade plywood. The wood itself is fine but the surface is just a bit too grainy to allow the board to be written on easily or to really be wiped clean.

I would like to make a replacement - what wood is recommended for making an outdoor blackboard and how should it be treated / primed?

Any advice from someone who knows would be greatly appreciated.

 

[Deluks]

Get some wbp plywood, glue some slate tiles to it.

 

[JohnD]

you could use marine ply with a Far Eastern Hardwood veneer, this is fairly fine grained and you can sand it even smoother if you want before applyng blackboard paint. I am guessing your old board is Birch or Spruce or something and the grain is raised (possibly due to weathering)

have a look at some sample WBP and Marine ply before buying it to satisfy yourself about the smoothness. Marine ply is more expensive.

You should seal the cut edges of ply to protect from water.

I don't know any reason you can't use a wood primer before the blackboard paint. This will protect the wood and you could use a couple of coats to make the surface even smoother. It might be worth trying that (on one side of the existing ply) before you buy new - it will be cheaper and less trouble. Use an Aluminium or General purpose primer, not an acrylic water-based one which is more suitable for indoor use. You wil have to sand off the existing blackboard paint first.

I presume you know you have to temper newly-painted blackboards by chalking them all over with side-on sticks of chalk and rubbing it off with a dry duster. this makes them easier to write on and clean. Blackboards that have been washed clean or are newly painted are difficult to use.