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Old 09-25-2016, 08:56 PM
Mad City Flyers Mad City Flyers is offline
Intermediate Rocketeer
Join Date: Jan 2015
Location: Madison
Posts: 70
Default V2 Fin Finishing

Finished the fins with external fillets using the RocketPoxy. As this epoxy is already thickened I did not add anything more to it like phenolic microballons or fiberglass.

I have to say that my feeling are mixed about the RocketPoxy for external fillets. The tape edges were not as clean as I usually get with the Great Planes 30 minute epoxy thickened with West Systems fiberglass and phenolic microballons. The only downside was a lot of sanding to get very clean and smooth edges.

External fillets:
  • Roughened inside edges with 80 grit sandpaper
  • Taped off the edges with standard painters tape.
  • Mixed the RocketPoxy 1:1 and let it sit for about 10 minutes prior to pouring into the fin joint.
  • Used a 1/2" piece of PVC soaked in rubbing alcohol to smooth the fillets followed by a gloved finger dipped in rubbing alcohol.
  • Let the epoxy set for about 5-10 minutes before pulling up the tape and smoothing again with a gloved finger dipped in rubbing alcohol.
  • After letting the epoxy set overnight - lots of sanding with 150 followed by 320 grit sandpaper.
  • Cleaned the fillets with a rubbing alcohol soaked paper towel and then applied a somewhat thick layer of Elmers Carpenters wood filler.
  • Wood filler was allowed to set overnight and then sanded hard to remove almost everything but a nice cleaner over layer that filled all the minor imperfections.

Almost ready for paint!

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