Hi Cian,
Your not the only one from Ireland, Ilive over in good old Donegal, and have just been co-opted across from the Yahoo water rocket board, and the IWRA.
Thanks for the email David.
As for the bottles over here, You can get the 75cl bottles that are used by Schwepps for tonic water etc. They are blown from the same pre-form as a standerd 1 ltr bottle, but becuase they are on 75cl the wall thickenss is much greater, around 1.2mm. These are good and safe for repeated 120psi launches and lawn dart landings. I have flown some of them more times than I can remember, and there still going strong after 3 years
Try to get the older bottles, the ones with the dimples on the neck, the new ones are realy thin walled, cutbacks you know, less PET to pay for.
If you only have thin walled bottles do the trick of shrinking one bottle over the outside of another. In one statick test on a 2ltr bottle I took it upto 380 psi, and still couldn't get it to fail, great for CO2 lauches.
Any way, all the best
Richard
Clear Skies, and stright flights.