Using a biscuit joiner, also referred to as a plate joiner, is the best and most secure method of joining two pieces of wood. Until the biscuit joiner showed up on the scene, you either applied glue to both edges and hoped the pieces didn’t move while the glue was drying, or drilled holes and inserted dowels - but if the holes weren’t perfectly aligned the result was still an uneven, unfinished-looking project. Learning to use a biscuit joiner is no more difficult than learning to use any another electrical tool. Plus, like most tools, once you have the basics down they're great fun to use. A quick note before we start: remember to use caution when using any power tool; and, of course, be certain to use eye protection.
As with any project, when you are going to glue the edges of two pieces of wood together you want to make sure that both edges are perfectly straight, with no hills and/or valleys. To test how well the edges of your two boards meet, simply lay them side by side with the edges you need to join touching. The boards should be of the same thickness and should align evenly when pushed together. If there are any gaps, then the boards should be run through a jointer (not to be confused with a biscuit joiner). Once you have the edges trued up follow these simple instructions:
- Lay the boards to be glued on a flat work surface, edges touching.
- Draw a pencil line across each joint in intervals of 8 inches or so. It's typical to start about 3.5" to 4” from each end. The line only needs to be a couple of inches long, and can be drawn freehand.
- It is also helpful to draw an X on each board to indicate the top surface, always keeping the X visible. Next draw a large V across all of the boards. This will show in what order the boards go when it comes time to glue them together, kind of like a puzzle.
- Be sure to adjust the biscuit joiner’s fence so it will make a slot in the middle of the edge. You don't want the slot to be too wide: for example, if you’re using 3/4" stock, make sure the fence is set at 3/8".
- Set the biscuit joiner on the surface of the wood, aligning the center mark with the pencil mark. After making sure you have the biscuit joiner fence laying flat on the board, cut the slot. Repeat this step at each pencil mark.
- Once you have cut all the slots, clean out any remaining wood chips, apply glue to both sides of each biscuit and in the slot, as well as the edges of each board. Finally, clamp them together. It's best to leave them clamped overnight for the best bond.