Has anyone tried using Balsawood?
Balsa wouldn't be my choice for a project like that. First off, it's expensive, and second it's extremely stringy. The material cuts raggedly, shearing off large splinters with every pass. It's good for model glider wings, since it's strong for its weight, but it machines poorly. Foam would be a better choice for your plug, since it doesn't have a grain structure. But it's messy to work with, and the dust clings to everything. If you're using polyester resin, a styrene based foam will need to be well-protected from it, since it will dissolve on contact. But that's the kind of foam you can cut with a hot wire, which allows you to remove the bulk of the material first. You can't do that with urethane foam, which otherwise cuts more smoothly, since the fumes are extremely toxic. But the urethane would be more resistant to the polyester. Epoxy resins are more compatible with foams in general.
