Gail Myers
Composites

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Homework

• Our homework was to design and make a 3D mold (~ft2), and produce a fiber composite part in it. I decided to design a boat that could possibly be used in my final project.

Challenges

• Designing using a 3D CAD program is a struggle for me, but I was able to create a simple boat.
• Figuring out the speeds and feeds for the ShopBot was time consuming and required lots of research.
• Aspire and creating acceptable toolpaths
• The 1/2 inch tool was not center cutting.
• Okay, it's a couple weeks later and I am still struggling with milling the foam mold on the Shopbot. Everyone in the FabLab, anyone who knows anything about that machine has been working, researching, trying and we don't have a solution. I have the design, I just can't move on to the composite phase. Plan B?

Designing and Milling

• I designed my boat in AutoCAD. I then converted it to an stl file, set the toolpaths in Aspire, and sent the job to the ShopBot. I used 1 and 7/8 inch pink foam AND 2 layers of that will be glued together.
• Correction: I WAS going to do that, but after weeks of issues, I just milled my boat out of 2 inch pink foam and it's just 1 layer. I used a 0.5" flat endmill. The speed is 12,000 rpm and the feed rate is 100 in/min.Thanks Scott and Tim for all your hard work on the ShopBot updates!!!! We had success, finally!.

Making the Composite

What a FUN process! We had a great time with this! It was a couple weeks after starting the designing process due to a slow down with the ShopBot. Creating the Composite: First, I cut several layers of plastic and padding. I chose burlap to keep things natural! Next, I cut several layers of an absorbent material to absorb the extra resin. For the vacuum process, a seal was created by applying plastic and black foam tape to the table (see pics). The material I put on top of the mold allowed air to get through to aid in the vacuum process but kept the material from sticking to the form, thus unmolding was easier. Mixing the resin composite and coating the burlap was a group effort. We worked together to help each other to stay within the time constraints for the pot life of our material. After we coated the burlap, I had to make sure to alternate the grain of each layer of material, which would increas the strength of the final product. I put many layers of absorbent batting on top and then the largest layer of plastic and cut a small hole into the plastic to place the valve for the vacuuming. After 2 days, we unmolded and my boat was amazing.





Design Files
Boat stl
Boat dwg