Are you sure that's 4/B and not A/Bschaibaa wrote:Ok, so the Baltic Birch I picked up is considered 4/B quality. s
The grading describes both sides of the sheet, and a sheet can have mixed faces - A/B or B/C for example.
Sheets are graded by the outside finish.
A means that it has no blemish whatsoever, ply can be varnished to bring up the grain and would only vere need 200 grit or finer to sand for preparation.
B is still a good smooth finish but may contain specs of gum, some filler glues and although you can varnish it, the specs may reject the varnish. B is more 'paintable' I have had some B grade delivered with well executed patches in them but strictly speaking B should not be patched.
C grade is rougher surface and will most likely contain some patches
D Grade is downright rough and ready and is used for boxing for concrete for example or boarding up your house in Florida before the hurricane hits
A is the dearest.........D is the cheapest.
It's weekend here but when my ply stockist opens on Tuesday, I'll get the sheet explaining grades from him and post it. Grading of ply is, as I understand it, an international standard code.