My newest project is something different for me, I'm making a music stand for a present. It involves bending wood to quite an acute degree, tighter than I've ever done before. After consulting with my friends in The Woodwhisperer chatroom I decided to stick with a technique I'm familiar with, bent lamination. The first thing that i had to do was to create a bending form, I cut a piece of 1/2 inch MDF to 24x12 inches, I used my beam compass and drew a 12 inch radius arc in one end. I rough cut it on the bandsaw and cleaned up the cut using my disc sander and finished it with a flexible sanding strip made from a strip of 1/8th inch thick Baltic birch plywood with a block of wood glued to each end for handles and 80 grit sandpaper glued to it with spray on adhesive. Once the template was true, I marked out three more blanks and rough cut them on the band saw. I glued each blank onto the template using small brads to lock them flush. I clamped the sandwich together and let it sit for a few hours.
After lunch I removed the clamps and used a flush trim bit on the router table to flush up the arc. I then marked a line 1 1/2 inch
along the top and drilled 1 inch holes every few inches to make clamping easier. I applied packing tape to the top to keep any glue from sticking to the form.
The legs of the stand are made from Curly Maple, I ripped 2 pieces 2 inches wide by 50 inches long and using the band saw I resawed it into 3, 5/16th inch thick pieces. To clean up the saw marks I ran each piece through the drum sander to a final thickness of 1/4 inch.
Next comes the hard part, gluing and clamping the laminates to the form. The open time on the glue is limited and there are many clamps that have to be tightened. After covering each layer in glue with a roller I taped them together to keep the laminates from slipping. Starting at the center of the arc I clamped the laminate sandwich to the form tight as possible. I alternated each side of the center to even out the pressure working the clamps as tight as you can and moving to the next, you won't always be able to tighten the clamp completely until you get some leverage from the next clamp in line. To get the last clap in place I had to resort to a long clamp to help lever it in place. You might think that you could start clamping at the top end of the arc and use the long straight end to pull the laminate to the form. You can't do this because the laminates must slip along each other to form to the contour or the arc, by starting in the center of the arc you allow the wood to move equally on each end of the laminate sandwich.
Once the glue has set overnight I removed the clamps and got only about an inch of spring back. I repeated the process of gluing and clamping for the second set of laminates. I scraped the excess glue off of one side and using a number 4 plane, block plane, and finally a low angle finishing plane flattened it. Starting with the arc sitting on the tablesaw table and held to the fence using a featherboard I ripped it down to 2, 3/4 inch thick legs. These are glued back to back to form a Y that makes up the front 2 legs. The second piece will be ripped to 1 1/2 inch wide for the back leg and glued to the front Y to form a tripod, more pictures in the next post will illustrate it better.
"I may not have gone where I intended to go, but I think I have ended up where I needed to be." - Douglas Adams
"I may not have gone where I intended to go, but I think I have ended up where I needed to be." - Douglas Adams
1 comment:
If I am imagining correctly, you're building a beautiful music stand.
The bent lamination technique you are using is exactly the same used in wooden boat building for boats with strong curves in their stems.
Waiting to see how the 3 leg pieces are joined... Get back to the shop and watch that glue dry.
Post a Comment