Thanks for the tips guys!
I have had it heat sealed twice because the blow out happens right at the end tip of the strut. I have already shortened it by about 4cm from the heatsealing. I always pump it up lightly to around 7psi(meant to be 10psi).
I tried emailing Airborne but no response yet, may give them a call. I think a replacement is the only way.
BTW where can you buy stormsure from? Boating supplies or hardware store?
Thanks again