Loose Fiberglass on a Shock Cord Mount

[lcorinth]

I'm building a PSII Nike Smoke. I wanted to do something more than just the traditional paper shock cord mount, especially since the shoulder of the nose cone goes 3 inches into the airframe, so it would be hard to reach for me to reinforce the mount with some wood glue over the top, as I do with smaller rockets. I know some people hate the trifold mount, but slathering extra glue to laminate them in place has worked for me so far.

Still, I wanted something stronger for this rocket.

I considered doing a PML-style, epoxy-it-to-the-tube mount. But since epoxy can be messy, I was nervous about getting it in there, and not all over the place.

I decided on a compromise: I used wood glue and a paper mount to tack the shock cord in place, then reinforce it with some fiberglass cloth.

When I met a fellow club member for coffee this weekend, I mentioned this, and he was nice enough to give me some fine fiberglass cloth. So, today I mounted it into the rocket.

I've never worked with this stuff before, and it was awkward getting it in there. I got the paper mount a good 5 inches or more into the rocket so the nose cone would have some clearance.

I coated the cloth in epoxy, then put it over the mount. It was really tricky getting it in place, trying to manipulate the soaked fiberglass with two dowel rods. I've never worked with fiberglass cloth before, and this stuff was pretty thin.

I covered the cloth with wax paper, then stuffed in a bunch of wadded newspaper to hold everything in place until it cured.

It mostly turned out OK, but there are a couple places where the cloth did not adhere to the airframe.



The mount feels really secure, but what's worrisome is in the back. There's a bit of cloth sticking up. I'm worried the recovery system might snag it and get caught. I need to tack this down with something.

My initial thought was to slather some more epoxy over top of that with a spoon (it's about 8 1/2 inches into the rocket) to smooth things over, but I think I've read that fresh epoxy will not adhere to already cured epoxy. Is that so?

Another thought I had was to maybe smear some wood glue over the area.

Or, tack it down with something like Avery labels, put in place with some tongs, then smeared over with wood glue. I'm just trying to smooth the whole thing over.

I need your experience and suggestions. Epoxy? Wood glue? Avery labels? Something else? I can't really cut the excess off - it's too far in there.

Thanks!

 

[mkadams001]

You will be ok putting epoxy over epoxy. Thicken it to peanut butter consistency.

I am presuming that the cloth is hard. You could sand it down with some sandpaper on the end of a stick.

 

[Rex R]

I have been known to inflate a balloon inside the airframe(with waxed paper between it and the epoxy), sort of a reverse vacuum bag deal.
Rex
sandpaper onna stick should work nicely to smooth out the offending bits.

 

[matthewdlaudato]

Glad that worked out Dan, should be plenty strong.

- The guy with the spare fiberglass!

 

[lcorinth]

Glad that worked out Dan, should be plenty strong.

- The guy with the spare fiberglass!

Yeah, thanks a lot, Matt. I think it'll work really great.

I managed to sad a good bit off with some sandpaper on a stick. I think I'll epoxy over the few rough bits I couldn't really sand off.

Once this bit's done, it's nearly ready for priming and painting. I haven't finished a rocket in months - it's about time I did!