Ive finally got round to pressure testing some re enforced bottles and a spliced bottle the results were better then i expected i started by testing the re enforced 2L bottle im not sure what pressure it actually failed at as my gauge i was using on the test goes no higher then 160 psi it filled for another 10 secs once it hit 160psi so i reckon 180+ psi so i think a safe launch pressure will be 115-120 psi.
This pic shows the destroyed bottle after the test the bottom of the bottle shows no stress as this was glued with sikaflex the neck of the bottle was not so good as this was not glued maybe glueing the neck will help out next time.
The test was put on a spliced bottle with re enforcing at the neck and bottom the bottle failed at 140psi which was more then i had hoped for i used a mixture of sikaflex 11fc and titebond glue for the splice and for the sleeve i used sikaflex again the failure point was near the sleeve and it looked as the bottle was sanded too much here are the destruction pics.
Ive been working on a new nozzle system as putting gardena nozzles in caps can be tricky and time consuming to make. The only draw back with this nozle is its weight 37 grams compared to just a nozzle and cap. But for people who dont want to much work and are not bothered about weight this will be perfect i will use this for small rockets only as larger rockets have to be on a very strict diet!!!!