The Technique of FURNITURE MAKING
TRUING OF SURFACED BOARDS
If a board does warp after it has been levelled, only experience will give the knowledge of how much it can be corrected when the construction is framed together. As an expedient, boards which warp in their width can sometimes be corrected by the old trick of wetting a level stretch of concrete floor, waiting until the water sheen dries off and then laying the hollow side downwards on the damp surface, weighting it if necessary. Alternatively, sturdy bearers can be cramped/clamped across either side, using scrap pieces to force the board over to the other extreme; but there is no guarantee that these measures will prove permanent. Thin sawn boards which are badly cupped and present difficulties in planing up can be panel pinned on the corners to the bench-top, the pins well punched in and the board surfaced, but the boards will resume their original shape once they have been released, and everything depends on whether the stiffness of the supporting framework will hold them flat without undue strain. The most satisafactory solution is to reject all boards which show pronounced movement, but sometimes it is a hard decision to take and therefore worth experimenting.