The guitar form

So its been a few days, works been a little busy, and i have been spending more time building than updating. But, nonetheless there are a few things that are new and exciting to talk about. The big one is the guitar form or mold, I has finished it! :-p

The guitar form is used in the assembly process of the box or body of the guitar. It maintains the shape of the body during the assembly of the guitar, when gluing the sides, top and back together. Using the templates I had, I traced out both the sides on Birch Plywood, I was trying to figure out how I was going to create a 2 inch offset line from the template. I remember watching a video on the Luthiers forum where someone used a 2 inch radius disk with a hole in the middle for the pencil to scribe out the width of the form. Unfortunately I didn't have this, and I wasn't exactly jonesin' to cut out a circle out of masonite either. But then the solution was staring me right in the face. I noticed that a CD looked like it was close to two inches between the inner diameter and the outer diameter. I pulled out my ruler, and sure enough, just a hair over two inches, that will work!! so using a old beat up CD I was able to trace a uniform thickness around my templates.

I managed to cut out the two masters where I took my time and patiently cut as accurate as I could on the scroll saw. Once completed, sanded, and matched to fit my templates, I could then trace out two other parts will make up the three part laminate for each side of the mold. The other two pieces were rougly cut, then glued to the master. The idea is, using a flush trim bit on my palm router, I could hog out the excess material up to the shape of the master leaving the exact same shape as the master. That way I don't have to cut the pre-glued billets of plywood to get my mold. I tried that already with six layers of MDF laminated together, and even though I was able to create the molds, they ended up not matching the template so they can't be used (lame). It ended up working really well, there was a slight learning curve with the palm router. That thing can kick if I'm not paying close attention to what i am doing. plus there was a few spots where I pulled it up at an odd angle and it cut a little nick in the final shape. Bugger! Least its nothing that will cause any problems with the shape of the guitar so I am not worried.

I didn't have to do too much sanding to clean up the final shape any. There still a few spots where I need to spot sand due to glue build up, but over all it turned out pretty well. I finished it up earlier this evening by adding the bolts to hold it all together. I picked up a 18-volt Ryobi Portable drill that I had my eye on for a while. Normally it went for 99.99 at Home D'Poe but they had it on sale for 49.99 so I couldn't pass that up. Bought the 5/16 x 3.5" bolts with a few fender washers, couple of lock washers, and wing nuts to finish up the mold.

Gluing up the laminated cutouts

Laminated side, ready for trimming

The triming process with my handy colt

Half way there, trimmed flush with the center

Other News, while I was working on this form, I also recieved my portable DC air compressor which I will be converting over to a vacuum pump to vac bag my back and sides. I found a really good site on vacuum bagging veneers and a lot of DIY write ups on bagging systems. very informative and a lot of good ideas for how I am going to approach the vacuum process. I'll probably have a post on the pump in the next couple of days or so.

Also, I finally ordered my veneers from I should be recieving my shipment on Monday. I settled on Koa for the backs and sides using Quarter Sawn Mahogany as the interior veneers. As far as the top goes I am still looking to use Redwood. While this is my very first guitar and I should stick to the traditional materials, I still like to experiment. From what I have read, redwood gives you all the good qualities for both Cedar and Spruce. Plus I like the look. I think my final decision whether I go with redwood, or spruce will fall upon when I get my veneers and see what the koa looks like. So far, thats pretty much been holding me up from buying the top wood as well as bindings and purflings, I want to make sure what ever materials I end up using will at least be aesthetically pleasing. But I did think that maybe I can use the excess peruvian walnut from my neck wood to resaw bindings. It has a real nice chocolaty color to it and I think it would look nice agianst the Koa and redwood. Plus it will tie in the neck better to the guitar. We'll see.

Anyways thats it for now, till next time.

Greg