RE: Scratch Built 1/8 Scale Azure AZ279 Build Thread
The plugs for the 1/8 model boat were cut from 4 pound density foam blocks. This is a relatively simple process, since a 4 foot long by 2 foot wide foam block is a standard size.
However, the plugs for the full size boats are cut from structures that are built up from wood, and spray on foam, since nobody makes 28 foot long blocks of foam. I will show pictures of an Azure AZ298, since I do not have any of the AZ 259. You will see the CNC machine cutting the rough foam.
Once the rough foam of the full size boat is cut, it is carefully sanded and primed to replicate the surface of a real boat. IE, it has to be perfect. I will include pictures of the full size boat after it has been blocked and sanded for weeks. You will also see parts like hatches and the windshield added on to verify the fit before the final molds are made off of the plugs.
This is where the main difference between the model and the full size boats comes in. Since the 8th scale model is so small, the details of the real boat can not be accurately scaled down in foam. The foam of the plug is too soft to replicate minute details and crisp surfaces, and spraying on primer will destroy all of the fine lines and detail that got cut into the plug.
So I had to create a "fiberglass plug" to do my finish sanding and body work on. I PVA'd (mold release) the foam plug, and made a rough, throw away mold directly off of the 8th scale foam plug. This would allow me to make a fiberglass plug, which is much better for sanding, and will retain its shape better than a foam plug. Unfortunately, I did not take any pics of the 8th scale hull plug that I used to make the rough mold, but the hull foam plug was undamaged in the process. It will not be needed again for the project though.
The 8th scale rough mold had all of the tooling marks, and rough surface of the foam transmited into it, so I carefully sanded all of the positive shapes of the hull in the mold. I molded it out of black gel coat, since this would show the most blemishes that I needed to sand. Here I sanded the trim flange at the top of the hull, and I also sanded the flats between the strakes, as it was easier to do in the mold. Basically, the rough mold was sanded only where it would be easier to fix issues, instead of sanding the fiberglass plug.