Today I finally got around to making spreaders/stretchers/clamps (whatever you want to call them) to keep the bent sides secure inside the mould. I have been meaning to make these since making my mould last summer, and have had the hardware for them since early this year.
To make these spreaders, I used leftover 3/4inch MDF from making the mould, 3 eye/eye turnbuckles (one for each spreader), and some scrap doweling. Each spreader is custom fit to my guitar shape, so it wouldn’t be much use for me to provide plans, but I’ll describe the steps that I took to make them.
I started by cutting out all of the pieces of MDF. For each spreader, I needed 4 pieces – 2 for each end. All of the pieces were the same width – 6cm, but each spreader required a different length in order to fit the mould. The pieces for the lower bout were about 12.5cm long, the pieces for the waist 6cm, and the pieces for the upper bout 8cm. One end of each piece was curved to match the curve of the sides. I used my guitar half template to mark the appropriate curve on each piece and then cut them all out on the bandsaw.
I then marked and drilled a pilot hole through pairs of MDF blocks to help with the alignment later on. These holes were drilled in the centre 13/16ths away from the straight end of each block.
Next, I excavated a spot in each pair of blocks to allow for a turnbuckle sandwich. To fit the turnbuckles I had purchased, I used a 26mm forstner bit and drilled about an 1/8th of an inch into the inside face of each block using the previously drilled pilot hole as a guide. I then used a chisel to carve out the rest of the material until the turnbuckle sandwich fitted perfectly.
Then I glued the sandwich together before cleaning up the sides with my disc sander. That tool is proving to be really handy!
With all of the faces smooth, I just needed to do two more things. First, I drilled a 3/8 inch hole through where the centre of the turnbuckle’s eye was buried using the previously drilled pilot hole to make sure that I didn’t hit any metal. I then drove a dowel through that hole. This step was probably not necessary, but I think it will make these spreaders last longer as there should be less of a chance of the turnbuckle becoming loose.
Finally, I glued a thin piece of cork to both ends of each spreader to prevent them from marking my sides. In the image below you can see the finished lower bout spreader:
When I am finished this guitar and have the time, I might put a coat of shellac or other finish on the MDF just to seal it and protect it from moisture, but for now they are working just fine! A big improvement on my previous clamping method for sure.
As you can see, the guitar build is going well – I have the soundboard braced with a lattice pattern, the sides are bent and laminated (in the same way I laminated the sides for the last guitar), the back is braced, and the neck is roughed out. If the next few days go as planned, I will have the box closed up by this time next week, so I will write a building update post when that is all glued up.
On a couple of different, unrelated notes, I thought that I would mention a couple of upcoming performance projects. Firstly, I am playing a concert in Selma, Nova Scotia in 10 days at 7:30pm on Friday, June 21st at Gallery 215. If you know anyone in that area or are from Nova Scotia yourself, I hope that I might see you and/or your friends there! I will be playing music from my upcoming CD, Vespers.
Speaking of which, the CD is nearly done!! I will have it by the end of July, so be prepared for many more references to and shameless plugging of this project over the next month. I will reveal the cover, a release date, and a place to purchase the CD in a week or two.
If you are in the Ottawa area, I am also playing a concert here on July 11th at 7pm at the Trinity Anglican Church on Bank Street.