Liteply is made from a relatively obscure type of wood and was originally produced to replace cardboard for kids' jigsaw puzzles. I think there are only three mills in the world which make it and two of those are in Spain. It is usually three laminations with the outer veneers being thinner than the core, and it is also bonded with a PVA or aliphatic resin glue, This isn't waterproof, although you can solve that problem by liberally coating the finished structure with resin or thinned polyurethane varnish. It sands like hard balsa; cuts easily with a heavy-duty craft knife and glues very well with aliphatic resin wood glue. If you steam it it will bend readily and retain the shape if held there until dry. I would suggest SLEC as a good source in the UK for this. They stock 2mm, 3mm and 6mm (from memory).
"Marine" ply is usually made of something like birch. The very thinnest plys are three-ply, while thicker types can be any odd number (typically five or even seven for modelling sizes) and they are bonded with a waterproof resin. This makes it "WBP" (Water Boil Proof) but also makes it much stronger, heavier and harder to work with hand-tools. It requires very little in the way of surface sanding in preparation for a finish. It will bend if steamed but it usually wants to spring back to its original shape, so I find it best to "overbend" it and then clamp it until dry. It will then spring back to something like the shape you need. I buy mine from a local timber merchant where the price of a full 8' x 4' sheet isn't much more than I'd pay for a 3' x 1' sheet from our friendly neighbourhood model shop. Worth bearing in mind if you're going to use a lot if it. O yes - if you want it to remain waterproof at the joints then you really need to use a waterproof adhesive like Cascamite or Aerolite 306.
Either beats the hell out of GRP and styrene.........................
FLJ
