I spent some time today radius sanding the top and back of the sides and end/neck blocks. After the last one when I had the radius dishes but no sandpaper for them, I decided that I would make sure to have sandpaper for the dishes this time. I looked around all over for 24" round sandpaper but couldn't find any for a reasonable price. Everyone wants close to $20 per sheet and that is pretty expensive. I went to Lowes and found rolls of 6" wide by 10 yard long rolls of 80 grit PSA paper for $14 a roll. I picked up a roll and used it for both dishes with enough left over to do another dish. The sticky stuff wasn't very sticky but once I got it all laid down, I went over the seams with a heat gun and that made it stick down really well.
I first sanded the top edges with the 30' dish until the blocks had a nice radius and all of the edges were sitting flat on the dish. Then I took the plan, measured the width of the body in 2" increments and then used my graph board to transfer the marks to the sides. I connected the marks with blue painters tape to get a line all around the body.
The last time I did this, it worked fine with one exception. The side view on the plans do not take into account that the waist is closer to the center of the guitar than the two bout sides. Because of this, the waist needs to be lower than the plans show to account for the radius. On the OM, I didn't think of this and I rough cut the sides to within about 1/8" of the tape edge. When I set it on the radius dish, I had to remove quite a bit around the edges of the bouts to get the waist to drop into the dish. I hope this makes sense, I know it sounds confusing.
Anyways, this time when I rough cut down to the tape, I made sure to keep about 1/4" additional wood above the tape on the waist locations. I used my cordless drill with the rotary microplane to do the bulk of the work. After that, I flipped it over and sanded to radius, carefully measuring the sides and ends to make sure that I didn't get the body too shallow. It went well with one small issue. Somehow, I must have cut the tail block just a tad too short. When I had the sides sanded to the final depth, the tail sides were about 2mm taller than the block. I though about just sanding it down to the block, but I really wanted to keep the body as close to the plans as possible. So, I cut a small shim of mahogany, rough shaped it to the block shape and glued it in place. Everything is in the warm room drying now.
Here is the 30' radius dish after sanding the top sides.
The sides after I marked the back edge. Everything above the tape top edge needed to be removed.
This is after about 10 minutes with my drill and microplane. Note how I have the waist higher above the tape line than the rest. This is to accommodate the depth needed for the radius dish.
Here it is, all sanded and sitting on the 15' dish. It fits nice and tight. No daylight at all.
Notice how the tail block is a little bit short. The sides are sanded to the final depth. Hmmm, I wonder how that happened.....
Here is the piece I cut and rough shaped glued to the block. I somehow did the same thing on the OM. I must be doing something wrong in my measuring to do the same thing twice.
Here is the sides with the 15' radius board sitting on the edges over the waist. It fits perfectly.
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