Australian/New Zealand Luthiers Forum

Hey there!

I'm about to make a new ply/mdf body mould for my acoustic guitars. And wanted to ask if anyone had any tips or specific ways of building the mould for cutaway acoustics.

I'd like to make a regular mould for my design, with a removable cutaway insert (so I can use one mould for both cutaway and regular). Has anyone done this, or is it always a complete separate mould for cutaway models?

(I couldn't find a post that answers this question but if it exists please link me!)

Also, I'd love to see everyone's photos of their moulds and general mould tips you have discovered during / after making them?!

(my first post in the forum, excited to be here )

Tiana

Hi Tiana and welcome to ANZLF.
Mould building is a rarely discussed topic, so thanks for raising it!
Here are a few of mine hanging on the wall. I throw them together fairly roughly and quickly from cheap and available material such as MDF sheets or plywood. They are definitely not pretty. My first couple were more solid and heavy, made by gluing multiple layers of ply. Now I usually do single layers of ply, separated by short strips of ply. But it doesn't really matter too much how it is constructed. Two halves, usually held together with a bolt and thumb-nut at each end (or sometimes just clamps). One of mine has a hinge on one end and a bolt on the other (no better or worse). I put small feet on either side so they sit a bit off the benchtop.

On your specific question of whether it is OK to have an insert for a cutaway section I think definitely yes. Here is one of mine. An essential tip in doing the cutaway is the slot cut into the mould shown by the arrow in this photo. This allows the side that is bent into the cutaway to extend beyond the other side that has wrapped around the bass side and across the neck block - and they meet at a right angle butt-joint.

The internal spacers - keep 'em simple. Ideally they need to stay in until both back and top are on. That means they should be small enough to be pulled out through the soundhole.

Some people get carried away with moulds...to the point where their moulds look better than their guitars