Procedure Overview
Below is the detailed procedure for how the second flight candidate fin can was manufactured. insert more detail
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- A respirator is required for all steps involving sanding fine particles like carbon fiber and phenolic
- A respirator is required when using colloidal silica before it is completely mixed into the epoxy. The respirator can be taken off once the silica is completely mixed UNLESS the epoxy you are mixing it into also requires a respirator.
- A respirator is required when using West Systems 3000 epoxy
- Gloves are required when sanding carbon fiber to prevent small splinters
- When using the Dremel, use safety goggles that completely cover your eyes to protect from stray projectiles
- Use safety goggles that completely cover your eyes when sanding so that fine particles do not irritate them
Here is a summary of the procedure, including the approximate time that each step took.SUMMARY OF FIN CAN MANUFACTURING
| Design fin can | Approx. Time Required | # People Required | Notes | ||
|---|---|---|---|---|---|
| Fin Design & Manufacturing | 36 hours | The more the merrier. | Manufacturing procedure and detailed breakdown described in "Hermes 2 Fin Design & Manufacturing" | ||
Design/make jigs | |||||
| Root bond jig | 3 | Allow for tolerance so fins fit, but don't make slots too loose. Make sure you have a top plate. | |||
| Fillet jig | 3 | ||||
Tube preparation | |||||
| Sand tube | 2 | Sand inside with flapper wheel so that it fits over the motor case | |||
| Tube layup | 6 | 2-4 | Rough up the outside of the tube before layup. | ||
| Root bond | 1 | 5-minute is ok, but if you have time, use a stronger epoxy. | |||
| Root fillets | Need 4 sets of fillets but it takes 8 rounds cause you gotta do the ends of each side separately (read below for more detail). You'll have to backtrack from when you want to do the layup to when each fillet has to be done by (can speed up using heat gun) | ||||
Layup preparation | |||||
| Laser-cut CF cutouts | |||||
| Spray-glue to wax paper | |||||
| Sand fillets | |||||
| Prep vacuum materials | |||||
| Layup | |||||
| Wet plies/weight | |||||
| Layup | |||||
| Put on vacuum bagging | |||||
| Vacuuming | |||||
| Oven Cure | |||||
| Set up oven/vacuum materials | |||||
| Follow epoxy cure cycle | 12 hours | Make your life a lot easier by assigning shifts (i.e. have 3-4 people helping so you don't have to sit in front of the oven the whole time). Even better, find access to an Autoclave so you don't have to adjust the temperature manually. | |||
| Remove vacuum materials | |||||
| Clean up edges | |||||
| Static load test | |||||
| Design/build jig | |||||
| Determine testing loads | |||||
| Static load test | |||||
| Analyze data | |||||
| Post-processing | |||||
| Sand fillets/outside | |||||
| Outer fillets on low spots | |||||
| Paint | |||||
| Total manufacturing time |
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Required Materials:
- Phenolic tube (INSERT LINKAirframe Tubing PT-6.0, 6.007" ID (https://publicmissiles.com/product/airframes)
- 60-grit sandpaper
- 220-grit sandpaper
- Carbon fiber (HOW MUCH)
- System 3000 epoxy (resin + hardener)
- Layup jig (wooden jig, metal pole, nuts and bolts to secure jig)
- Mylar
- Squeegees
- Popsicle sticks
- Epoxy boats or paper cup (for mixing epoxy)
- Painter's tape
- Scissors
- Ruler
- Acetone and shop towels (to clean up epoxy on squeegees)
- Gloves
- Safety goggles
- Respirator
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