The correct cutting of veneer and the precise joining of veneer sheets determine much of the quality of the final result. Well-fitting joints create an almost invisible transition between multiple sheets of wood veneer.
Working with veneer starts with carefully cutting the veneer sheets. It is important to cut the sheets slightly larger than the final dimensions (one centimeter), so you can trim away the excess edges after gluing the sheets together.
If you want to size several sheets at once, it is handy to clamp a board to the veneer and guide the knife or saw along it. This keeps each veneer sheet even.
Trimming: cutting the veneer sheets to the required length can be done in several ways. Use a sharp utility knife, scissors or veneer saw. The most common problem is that the veneer splinters when the saw or knife runs along the edges of the sheet. Prevent this by always cutting from the edge toward the center. Push the saw away from you when cutting the nearest side and pull the saw toward you when cutting the far side. Saw a few centimeters in from both edges and then cut the middle.
Cutting to width: often veneer sheets are not wide enough to cover an entire sheet, so it is common to join multiple strips together. Before you can join these strips, the edges must be cut straight. Do this with a sharp utility knife or veneer saw, cutting along a straight ruler or batten. It is crucial to cut with the grain, so you prevent the fibers from coming loose and the veneer from tearing or the cut line from running off straight. If you use a veneer saw, you have less of this problem.
Once the edges have been cut, you can join the veneer sheets with special veneer tape and/or masking tape.
Place the sheets against each other and tighten them with tape. Start with blue masking tape on the back and turn the sheet over to tape the visible side with paper veneer tape. Then remove the blue tape from the back to prevent air bubbles. Dampen the veneer tape with a sponge and then quickly press it down with a lukewarm iron for an immediate bond. Store the taped veneer sheet between two pieces of plywood to keep it flat and safe.
It is helpful to hold the joints up to the light ; if light shines through, you know the joint is not perfectly tight.
Joining can also be done during gluing. Do this by letting the strips overlap slightly and heating the overlap with an iron. After that, you can cut through both layers of veneer with a straight ruler or batten. Remove the lower cut strip from beneath the lower veneer layer. In this way, both sheets will butt together perfectly.