Monday, February 6, 2017

Estes Sprint XL #7224 Build, Part 5, Fin Shaping

In the original Sprint kit you had a choice to either airfoil the fins or round the edges.
These new instructions say to round just the leading edges. That didn't make much sense given the shape of the fins. I decided to round it all - the leading edge, outside tip and trailing edges.

The edges are knocked off with a sanding block with 220 grit. (See inset)

The real rounding is done with a small piece of 220 grit and fingertips. The final round is shown in the inset picture.

The fins were filled with CWF and sanded smooth. One fairly thick coat of Duplicolor Filler/Primer followed. The filler/primer fills any remaining wood grain.

I read on the forums where some builders do many applications of filler, then three or four coats of primer sanding between coats.
That's an awful lot of work!
For me, brush on one coat of CWF and sand, then one (somewhat heavy) coat of Duplicolor spray primer/filler and sand.
Many use the cheaper Rusto Filler/primer. I tried it and it was very rubbery, too hard to sand. Try the Duplicolor Primer/Filler once and you won't use anything else.
White undercoats follow that, usually with a bit of smooth sanding to remove any rough spots.

1 comment:

  1. Interesting that if it's recommended to airfoil the fins or round the edges that the cover image of the Estes Sprint XL has squared or flat edge.

    I liked it when they actually built a model and airbrushed it a bit for a cover image...