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| 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 | 2 | Allow for tolerance so fins fit, but don't make slots too loose. Make sure you have a top plate. Second Set (correct fit):
First Set (collar too small)Too small:
|
| Fillet jig | used H2's | N/A | Two wooden pieces with a U-shaped slot on which the fin can rests horizontally. |
| Fillet tools | 2 | 1 | |
| Tube preparation | |||
| Tube layup | 6 | 2-4 | Rough up the outside of the tube before layup. |
| Root bond | 2 | Used 5 minute epoxy because this is a practice fin can. Noticed gaps between the fins and the collar. | |
| Root fillets | 6 | Did two fillets a day for a total of 8 fillets over 4 days. Degassed Systems 3000 epoxy in the vacuum chamber before applying epoxy to fin. Need to sand the fin better. | |
| Layup preparation | |||
| Laser-cut CF cutouts | 4 | 2 | Be careful not to laser-cut over the taped edges of the carbon fiber squares that you use for the cutouts (the tape will be difficult to remove and fray the fibers). Also, don't spray glue wax paper until after laser cutting because the wax paper might catch fire or start smoldering in the laser cutter. |
| Spray-glue to wax paper | 1 | 2 | |
| Sand fillets | 0 | If you do the fillets right, you should barely have to sand them. Make sure to wear a respirator whenever sanding fiberglass. | |
| Prep vacuum materials | 3 | 4 | The shape of each vacuum bagging material (peel ply, breather, bleeder, vacuum bag) should be a square, and you need four squares of each material since there are four fins. The width of the cutouts should be around 4 inches longer than the tip-to-tip distance (not too long or too short). The length of the cutouts should be around 4 inches longer than the fin collar (see images to get an idea of the size). The sizes for Rusty were not correct. Dusty will have the correct sizes listed. |
| Layup | |||
| Wet plies/weight | |||
| Layup | 8 | ||
| Put on vacuum bagging | 2 | ||
| Vacuuming | 24 | Watch the gauge on the vacuum pump to make sure it drops to at least -26 mm Hg | |
| Oven Cure | |||
| Set up oven/vacuum materials | |||
| Follow epoxy cure cycle | 12 hours | See oven shift google doc. | |
| Remove vacuum materials | This takes a while, but it can be done with patience. Make sure you don't lose track of any of the vacuuming supplies (like the vacuum pump attachment) when you throw out the bagging materials. | ||
| Clean up edges | We didn't clean up any edges because this was a practice fin can. | ||
| Static load test | This section has yet to happen because Shannon and Charlie are working on a fin can test jig. Will update later. | ||
| Design/build jig | |||
| Determine testing loads | |||
| Static load test | |||
| Analyze data | |||
| Post-processing | No post-processing was done for Rusty | ||
| Sand fillets/outside | |||
| Outer fillets on low spots | |||
| Paint | |||
| Total manufacturing time |
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