Fins
Fins
The material we use to make fins is a some rectangular shaped plastic rail that is for sale
in most DIY shops.
Sometimes we use oridinary flat plastic sheet (lexopan) to cut fins from.
We use 2 types of glue to build water rockets and to attach the fins.
I do not know what it is used for, but it is ideal to cut fins from
since it already has a perfect recangular bend in it that makes it easy to stick it
to the bottle with some silicone.
To attach them to the bottles is not easy since the material is very thin, which makes
it difficult to glue them to the rocket.
One way around this problem is to first glue a printed ciruit board glider to the bottle.
This is like a rail in which printed circuit boards are held. You may find 5 to 10 of them
in all shapes and sizes inside any old PC. You may even break open your new PC to get a hold
of them.
The left one is BISON construction glue, primarily intended as wood glue, but very
similar to PL Premium. It is a polyurethane glue and we use it for all bonds that need
to be very strong, but not very flexible.This glue takes a couple of days to cure fully.
The glue on the right in the bulk package is SOUDAL FixAll. It is very similar to normal silicone sealant but
much stronger. It also remains flexible after curing. We use it primarily to attach
nose cones and fins to bottles. The attachment of the fins is very strong, and it is
my practical experience that they will survive all kinds of lawndarts without getting
loose. With normal silicone sealant I had fins that dropped off during launch or after
a lawn dart. NOT yet with this glue !
