Duke University Motorsports is a student group that designs and builds open wheel, single seat race cars to compete in the Formula SAE competition sponsored by the Society of Automotive Engineers. The team consists of Duke students from both Pratt and Trinity, in all classes. The purpose of the team is to provide students with a way to gain practical design and manufacturing experience in a fun and challenging setting.

Sunday, April 15, 2012

Making Bodywork, Part 2

We're a few steps closer to completing our bodywork now.  All the molds are put together, and we're done with the initial sanding of two and a half of the pieces.
Our five mold pieces, slathered with epoxy/talc filler and waiting to be sanded.
Pictures and updates after the jump.

 After all the mold pieces are milled, they are glued together.  I used gorilla glue, which works pretty well, but takes a while to cure.  To hold everything in place while it was curing, I used a few dabs of hot glue, making sure not to let the glue get too hot and melt the foam.
Starting to put the molds together

First few pieces of the nose cone

gluing a side panel together

finishing the nose cone

finishing the other side panel
Once all the molds are put together, we slathered body filler over all of the molds.  This gives a nice, strong, and sandable surface that will eventually be a lot smoother and more durable than the bare foam.  Unfortunately, this is a lot of work, but we have the time right now, so we're going to go through with this process.

Bondo is based off a polyester resin, which eats foam, so we had to make our own body filler with an epoxy base.  We used talc as a filler (it's cheap), mixing the two in probably 2:1 ratio (talc:epoxy), mostly by feel until the mixture was a nice, thick paste that didn't run.

Pieces after the first layer of epoxy

After two layers of epoxy

After letting the epoxy cure, we have to sand everything smooth.  We're still in the process of doing that, but let me tell you, it's a royal pain.  This stuff doesn't sand too easily, and it's taking ~3 man hours per piece.
Sanded piece next to unsanded piece
After we get all these pieces sanded, we will have to apply another coat of touch-up filler to fill a few small dips and depressions, and then finish the surface by sanding one last time.

After milling all the foam pieces.  We filled up our big trash can 4+ times with foam when cleaning the garage.
Garage after cleaning.  This is a rare view of the garage.

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