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Waited to cut excess off peel ply, release film and bleeder fabric until started vacc bag
5. Tip-to-tip Layup
Required Materials:
- System 3000 High Temp Epoxy Resin + Hardener
Mark centerlines on tube and CF cutouts
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For the tip-to-tip layup, we used a total of 6 boats of epoxy. Each boat weighed 118g, not including the mass of the epoxy boat itself, so the total mass of epoxy used for the tip-to-tip layup was 708g.
6. Vacuum Bagging
Required Materials:
- Vacuum tape
- Vacuum bagging materials from previous step
- Painter's tape
- Layup jig (wooden jig, metal pole)
- Scissors
- Vacuum pump (pump, fixtures)
- Respirators
- Gloves
Vacuum bag was 32 x 38" (this is TOO BIG, make smaller next time. For the test fin can though the bagging was too SMALL, so find a good middle ground)
Used layup jig to support tube
Make sure to run fingers along fillets so that they don't bunch up and end up with creases after the room temperature cure
Leave vacuum pump on overnight, making sure window is open to avoid vapor build-up
7. Oven Cure (see attached "Oven Cure SOP" for more details)
Positioned fin can horizontally as shown, because there wasn't enough vertical space in the oven we used. This may have caused the fins to splay (weight of the tube + epoxy loosening --> fins move), so in the future we should position it vertically. (try taking out the rack, for example)
Check the cure cycle for whatever epoxy you're using. In this case, we used System 3000 High Temp Epoxy, and the cure cycle is detailed below. Note that the epoxy changes from clear to amber-colored after the cure is completed.
Cure Cycle for System 3000 epoxy
- Increase from room temperature to 150F at a rate of no more than 2-5F per minute
- Hold at 150F for 3 hours
- Increase to 250F (no more than 2-5F per minute)
- Hold at 250F for 3 hours
- Increase to 300F (no more than 2-5 per minute)
- Hold at 300F for 3 hours
- Ramp down to 100F (no more than 2-5F per minute)
- Do not shut down the oven and leave it to cool down
8. Post-processing
Vacuum bagging materials were difficult to remove, but not impossible
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