How to build an all Carbon composite airframe on an aluminum mandrel.

Process

First, make sure you are aware of the health hazards of uncured epoxy and take precautions. Be aware that big batches or very thick laminations of epoxy have a potential of a runaway exothermic reactions. That could mean smoke and fire.

Place release coated mandrel on the roller stand and insert the heater piccolo. Mix the epoxy (in small batches to avoid exothermic reaction) and brush the epoxy onto the fabric. Continue rolling fabric onto the mandrel while brushing on enough epoxy to wet out the fabric. Keep brushing the excess resin toward the dry fabric. When you get to the end, the edge tends to stick up a bit. Place a piece of tape over the end of the wrap as shown in the photo. This will reduce the sanding required. Use the paint roller to squeeze out excess resin.

Turn on the heater to begin the resin cure. Monitor the mandrel temperature to hold about 120 degrees F. This will cure the epoxy quickly and provides some expansion of the mandrel during cure to ease mandrel removal later.

After the epoxy is cured (dry to the touch), turn off the heater allow the mandrel to cool. Provided your wax and release coat was adequate. the airframe should break loose and slide off the mandrel with a little bit of muscle.

If you're intending to push the performance envelope, a 150 degree F post cure is wise.  If you're going for extreme performance, you probably already have the equipment to do a complete vacuum bag process and oven cure with high temperature epoxy.

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