Week 14:
Composites

Assignment:
Read the material safety data sheet & technical information for the resin you are using.
Design & Fabricate a 3D mold and produce a fiber composite part in it.

Composites: Fibers in a resin matrix
Fiber: Cut sheets down to size of mold.  Emerge/coat in resin then lay into or onto the mold.
Burlap:  Natural Fiber – don’t need breathing masks while using.  Multiple layers create less flexibility.
Matrix:  Epoxy is most common.  Use good ventilation.

Materials I needed for the Assignment:
Epoxy Resin CLR-TDS CLR-MSDS
Burlap
Space Saver Bags
Breather Fabric
Release Fabric

Steps I used:
I modeled the form in Inventor.



Set up the model to be cut using G-Codes in Fusion 360. (see week 12 for Fusion 360 and styrofoam example)

Then I used the CNC router to cut the model out of 2” Styrofoam.


Once finished I used Gesso on the Styrofoam to give it an extra layer to help the mold release.


I sprayed the Gesso with release spray (same spray I used in week 12).

While this was all drying I got the rest of my materials ready.  I cut the burlap to the size of the mold and cut darts into the corners.


Once I had all of the materials ready and my gloves on, I mixed the epoxy resin 2:1 ratio.  Mixing for at least 2 minutes to make sure the parts were well blended.

I used the following diagram as instructions for layering.

Then I started coating each layer or burlap one by one and laying them on the mold.  I did this 6 times (6 layers of burlap).


Next came the release fabric and then the breather material.


Once everything was put together I slid the whole project into a vacuum bag (with the help of Jeff) and removed the air.




The mold started to get warm instantly.  It got up to 152 F at its warmest point.

Then the mold started to cool.  After waiting 24 hours (I waited just to be sure) I removed the mold from the bag.  It easily released from the bag.  I made the mistake of wrapping the release fabric and breather material around the Styrofoam so that was a little bit of a challenge to pull apart, but once I got over the corner it released from the resin quite easily!

Now you can see the finished burlap centerpiece for my dining room table!

Week 14 Photos