Reinforcing Mitered Waterfall Edges on Desk
I would love to get some advice on a large desk I’m building with mitered waterfall edges. The plans I am following don’t call for anything beyond glue on those miters.
I am wondering if I would be unwise of me to not reinforce those waterfall edges with something beyond glue.
I’ve attached a few pictures to show what I’m talking about.
I tried using biscuits but couldn’t get them to work. I think because the desk top has to be laid on top of the base in a way that I can’t move into the angles of the biscuits correctly. I tried and tried but ultimately filled in the biscuit slots I had cut.
I am planning on using hide glue and clamping really well. The miters, in theory, don’t support any real weight but they will need to be strained a bit to be clamped into place and stay there. The real weight should be supported by the center of the carcass/base, which does have biscuits along the upright butt joints into the top.
I would appreciate any advice on whether additional reinforcement is necessary, and if so, the best way to do it without compromising the look of the waterfall edges. Thank you!
Replies
L tenons made out of Baltic Birch..
https://www.finewoodworking.com/2016/03/30/add-muscle-to-your-miters
The Baltic Birch version would not work for the OP. They are intended for mitered connections, like picture frames with wider surfaces.
Technically the OP has a beveled corner connection with ¾" plywood or stock, sometimes called a case miter. He could use the other two options in that article but it would be a lot of work and possibly difficult to cut the mortises needed depending upon his tools. Since I believe from the pics the lower assembly is already completed.
Assuming that the joints are well cut and fit well, glue should be enough. The biscuits or some splines could help with alignment during glueup and clamping, but you are essentially building 3 boxes side by side and the combination should be plenty strong. If the waterfall ends were hanging down without any further support, the answer would be different. But, they will also be supported along the vertical edges as well as the bottom (a box). So, you will be fine.
Yes on all the above. A spline would be more than enough and fairly straightforward to implement.
Spline would do fine. Perfect application for a domino if you can get your hands on one.
If you decide to go just glue you can probably "clamp" the whole assembly with some stretchy painter's tape like frogtape.
+1 on using splines. You can cut them with a shop-made router base jig. A lock miter bit might also work.
I don't think splines are going to work any better than biscuits, since they essentially are just a continuous biscuit.
Although I am curious why the OP could not get biscuits to work. We're the grooves cut perpendicular to the beveled edge? Was the lower assembly glued previously and fully set so that the sides were rigid? If so splines will give exactly the same results and I can't imagine how you would cut a slot in the lower assembly. You may be able to slide a loose fitting spline in from behind, if you can cut the slots, but it could be tricky give that it will swell and tighten from the moisture in the glue.
There are various commercial connectors that might work. This one is intended for knock-down furniture but it could be glued in place with epoxy or polyurethane glues, the hide glue probably would not be the best choice. This would permit a straight down motion to place them and not conflict with the biscuits in the vertical dividers.
If as I believe, from the problem you describe and the pics, the lower assembly is already done I think you are going to need to trust the glue only joint.