Spoke to several thunder cat and rib repair shops, they use it, the hyjacker I previously spoke about are actually pvc.
They recommend latex from a fibreglass supplies it's all synthetic so acrylic and a lot cheaper.
Unfortunately it didn't work, my hyjacker holds air at 8 psi for a good few hrs before you notice a difference in firmness to compared to it twin before and after I used the sealant. I put 500 ml in rolled it over and around etc, I noticed the bit left in the sauce bottle hadn't cured, so does that mean if I use a litre there's a good chance it won't cure for some time? I have built a rotisserie for my next attempt, just like to know more on the technical side of the latex. It obviously works for some, Volksglass at Springwood , Brisbane stocks it, I will ring him but he is a expert on fibreglass and only uses latex for mouldings.
Any suggestions, I hope I have got it right