Fiberglass Water Rocket

Again it's been way too long since I posted something here... Time to update!

I'm still struggling with splicing bottles, every time I give it another try the splice looks good but when I pressure test them they fail at < 100 psi. The problem seems to be that the bottles just aren't strong enough and they delaminate. Is PL Premium really the only glue that works? Hope I can get my hands on a tube of PL Premium some time to test this...

So I switched to another project, I first wanted to try to build a rocket with a FTC pressure vessel but unfortunately FTC is not a common product here in the netherlands, there are some online stores that sell FTC but they charge 25 euro shipping costs! That's way to more than I'm willing to spend on a few pieces of FTC.
Inspired by Aircommand Rockets I decided to give fiberglass a try. I just wanted to make a thin walled fiberglass pressure vessel since I'm not (yet) aiming on high pressure rockets.
The method I used is described on the Australian Rocketry Forum ,the same topic Aircommand Rockets refers to in their Shadow build log but this is a less complicated method which I thought would work for my project.

In this topic rocket_troy says:

these days I much prefer a more foolproof, cleaner and simpler method that always results in a very effortless slip-off removal. This simply involves laying 1 or 2 coats of newspaper around the mandrel and coating that with packing tape - ensuring the entire area to be coated or laid up over is totally sealed with the tape.

So  I gave it a try.

Fiberglass tube curing

Cured and mandrell removed

Pressure testing

Now that was easy!
Rolling the tube was pretty straight forward, first a layer of newspapers was wrapped around a PVC tube, than the newspaper was covered with packaging tape. Slowly wrapped fiberglass cloth around it and at the same time added epoxy. I waited 48 hours when before I removed the tube from the mandrel and it just slipped off.
Then I glued the end caps in and it was pressure tested to 150 psi.

And one thing leads to another.

Fiberglass pressure vessel 5,2cm dia 100cm long

End cap

First flight (and last flight to date)

I tried to launch this rocket with drop away boosters but due to a leaking o-ring (and spares left at home) this flight was cancelled.

Fiberglass water rocket with drop away boosters

I hope I can find the time to give it another try soon...