This is a technique that I use to make fillets at the fin/BT joint so that they come out smooth and even.
1) Sand the location where the fillet will be to roughen it up.
2) Clean
this area of any dirt or oil.
3) Using a popsickle stick or toung
depressor(depending upon fillet size) press it agains the joint were the fillet
will be noting where the curved part of the wood touches both the fin and BT.
This will form the shape of the fillet.
4) Using the position found it step 3
put masking tape on the BT this distance from the fin(~1/8in).
5) Using the
position found it step 3 put masking tape on the fin this distance from the
BT(~1/8in).
6) Put masking tape on both ends where the fillet will be. Make
sure there is no BT exposed at the aft end of the fillet so the excess epoxy can
be scraped off.
7) Mix up a batch of your favorite epoxy. I like West
systems. Also add some filler to strenghen it. I have had success with as fast
as 5min epoxy. Just remember you will need at least 1 min to complete two fillets
;-).
8) Apply a generous amount of epoxy to the fillet area making sure to
only get it on the tape and the fillet area. If a little dribbles where you dont
want it clean it with a paper towel and alcohol. PIC, PIC
9)
Starting at the top end of the fillet wipe away the excess epoxy with a popsickle
stick or toung depressor being sure to keep it pressed into the joint so the
curved end forms the fillet.
10) Remove the tape carefully to keep the epoxy
off yourself and the rocket.
11) Marvel at your perfect fillet while waiting
for the epoxy to harden. PIC, PIC
One thing I have found with this technique is that it works best with thick epoxy. If its too thin it will run off the ends before it hardens. In this case you can leave the tape on until it starts to firm up. If you do this it is very important to get the tape in the right place or it may damage the fillet.
Good luck
