Reflexions: Preparing for Carbon Fiber top of our robot

Carbon Fiber preparation

We began preparation this past week for our carbon fiber top of our robot. Lead mentor, Scott McMahon, is leading the charge of the process. It is a process that will take a little over a week for completion but it is very exciting for the students to be involved with such a cutting edge technology.

We began with pink insulation in 4'x8' sheets purchased at Lowe's. The protective barrier plastic was removed from both sides of each sheet. It was cut into 3'x1' strips by the students. This process was done a number of different ways but the most effective was to score the material about 1/4' deep along a utility knife. The material then was snapped along the score line. This created a very straight and clean line. The strips were then adhesived together with Loctite High Performance Adhesive. After the sheets were adhesived together, we used an electric hotwire to trim the block to into a rectangular block. The form was cut into the shape of the form using a pattern that was cut out of MDF. The block was then coated with a light all purpose joint compound. The block was allowed to dry out over night. The surface was sanded to attempt to create a smooth surface on each side. A second application of the joint compound was applied but this time it was thinned with some water. Fibertape was used were cracks had developed in the surface due to the foam sheets beginning to come apart slightly. The compound was allowed to dry again and resanded with sheetrock hand sanding blocks and 220 grit sandpaper. The final step was to use a repair joint compound for holes and cracks. This material sets in less than 10 minutes. It allowed us to create a very smooth surface with as few as possible dents, holes and hollows in the surface. The foam mold was sealed to the table using modeling clay.

A temporary painting booth was created in the shop using two tarps suspended from the ceiling with binder clips. The tarps were joined at the ends using the binder clips as well. A paint table was made using a large lazy susan with a piece of plywood on top of it. Four 1"x1" square pieced of tubing were placed under the mold on top of the plywood. This created a work surface that could rotate rather the painter having to move around the mold.

Epoxy resin was prepared by mentors Joe Hershberger and Scott McMahon. A air compressor was used with a spray gun to apply the material to the mold. Respirators were worn to prevent from inhalation of the fumes. A makeshift ventilation system was created using the shop vac. The shop vac hose was placed in the painting booth while the shop vac was located outside the back door of the shop. It was turned in this created a ventilation system to remove the fumes from the temporary painting booth.

The finished product is a mold that now has a very smooth sealed surface. This will be allowed to dry for 24 hours before continuation of the process occurs.

The carbon fiber to should be completed over the next five days. The steps will be detailed as they occur here.

The following shapshots give a small glimpse into the process from a sheet of foam insulation into a nice looking mold.