Monday, April 10, 2017

PML Lunar Express Build, Part 8, Getting Epoxy Fillet Ready

My experience with epoxy fillets is pretty small. Here's a technique for masking the fillets I learned from the Rocketry Forum.
For me, fillet width or thickness should reflect the size of the rocket. Big rockets get bigger width fillets, small rockets get smaller.

To mask a consistent width epoxy fillet, find a clean dowel. With a soft pencil, mark up the sides of the dowel end at the 6 and 9 o'clock positions.

Rub the dowel back and forth down the root edges of the fins transferring the soft pencil from the dowel to the rocket.
This will eave a consistent spaced line on the rocket body (in this case the tail cone) and the side of the fin.
The transferred pencil line is the masking line for the epoxy fillets.
You will want to use masking tape the keep the runny epoxy central and in the fillet areas.

This model was harder to fillet mask because of the tail cone curvature. The fin mask has mall cuts to allow the tape to run in a curve.

Here's the complete mask for one fin.
You will also need to mask the leading and trailing edge tips ends where the fin meets the body.

1 comment:

  1. Masking for fin fillets is the part I hate about a high power build, especially when the amount of masking in measured in feet, like with my Madcow AGM-58. I also learned the technique you used from TRF and use it on every high power build.