darren wrote:Runningdog wrote: I prefer building guitars to making molds.
that's what I was trying to say!
For those (like me) who also enjoy making molds and other tooling, but don't have their own CNC, you might want to consider finding someone local who does. They can easily cut out a mold shape for you, with holes for alignment pins or even hinge pins, like the ones that LMI sells.
Here is a website that lets you search for people across the country who have some sort of CNC capability they would like to share (usually for a fee).
http://www.100kgarages.com/
However, being someone who builds jigs, fixtures and tooling almost every day, your time would have to worth very little compared to the cost of buying something off the shelf - especially if there is something readily available for what you are building. If the mold is available for the kit you're building from the same source your buying it from, you'd be nuts not to get it for $100.
(Of course, I am nuts... and since I'm doing custom shapes, I'll need custom molds)
If you are going to make your own, I would use 4 layers (1/2" or 3/4" material) and use a center hing pin, the top and bottom layers having male ends, and the middle two pieces having female ends (look at the LMI molds to see what I mean).