Epoxy Rivets for Fiberglass?

I am preparing to build my first all fiberglass rocket. It has been in the build pile for quite some time, as I am a bit apprehensive. Nope, I still haven't built my Wildman Drago

At this time, I can't justify the $$$ for the high end epoxies, like Aeropoxy, Proline, West Systems, etc.

I have had extremely good luck with using Devcon 2 Ton Epoxy on some of my scratch built low and MPR's.

I think it may work well with fiberglass, as well.


Question;

I am thinking of drilling small holes just above the root edge, to allow the epoxy to seep into and through the holes, and bond with the other side of the fin on the motor tube.

I've done this to adhere Lexan fins to (unknown)plastic body tubes, and has worked very well.

Before that, I made cuts into the root edge with a coping saw, but it seemed the 'through-holes' were stronger, at least with my Lexan finned oddrocs.



Another (just now) thought;

Being a TTW fin, it would also make sense to drill holes in the fins at the outer body edge under the fillet.

Basically, the fiberglass fin would have two sets of small holes for the epoxy to bond 'through'.

Obviously don't make Swiss cheese of it, but drill small enough holes, reasonably spaced, as to not weaken it as much.

Make sense?


:confused2:

You are mating fiberglass fins to a fiberglass tube, this correct?
If so, the best and strongest way I know of from years of working with fiberglass is to use fiberglass resin and cloth, not mat. You easily fillet over the cloth & resin with epoxy, SMS panel adhesive or other perfered filler.
Holes in fiberglass has a tendancy to produce a release point for stress yielding an origin for cracks to start.
But my knowledge is in the automotive field, not rockets. I'm not past the paper body tubes yet.

McKailas Dad said:

Obviously don't make Swiss cheese of it, but drill small enough holes, reasonably spaced, as to not weaken it as much.

Click to expand...

Many people like to do this, but my opinion is that this doesn't help much because the epoxy is not that strong in shear with small cross section. Just roughen the surface with coarse sandpaper or a Dremel. If you inject the interior fillets the Devcon will work OK, though you will have to thin it with alcohol. See the instructions for any Wildman kit.

That said, US Composites 635 thin epoxy is cheaper then Devcon by volume and easier to tailor the viscosity. My L3 rocket (Wildman Extreme) did fine assembled with this.