KABOOM!! help with rolled paper tubes...

[Zippiot]

Well I made a few different test rocket motor tubes...each worked greatly then failed miserably...
Each motor made useable thrust for about .75 seconds before they blew out (in the same place).
both motors had the same amount of propellant but one had a thicker sidewall (4mm) and a larger hole down the middle through the propellant. The other had a 3 mm thick sidewall...but both failed so I assume they need to be thicker.
Only problem is I used printer paper, the long way...so unless I can find longer pieces of paper or a good way to double up they just dont seem to be a working idea...

Anyone out there have success using this or a similar method?
I guess I should aslo say they had .5 inch id

[bob000555]

what where u using as propelent also if a crack gets in the propelent it can cause a pressure jump and an explosion

[Zippiot]

Standard 60-40 rcandy, no cracks.