I use a piece of glass that was actually an electric commuter train window. Can't remember where I got it from but I know it was obtained legally before anyone thinks otherwise. :-) As for sanding I can't remember where I picked it up from, I think that it used to come in some resin N scale freight car kits that I used to build when i was in N before going back to HO, but I have some pieces of very hard foam rubber that I have glued to pieces of ply, enables me to put flat pressure evenly on the casts of the sides of cars. Couldn't be without the thing now.
---In STMFC@..., <tyesac@...> wrote :
I got by with something even simpler. 12" square granite floor tile less than 3/8" think, but still flat enough & very stout. A tile shop should have loose stock available on a price/piece basis. I had some left over from tiling a fireplace hearth.