I am vacuum bagging the hull of a boat and the sealing tape isn't sticking well to the fibreglass.  The fibreglass was laid 7 days ago. I have tried washing thoroughly with acetone and also a light sand, but tape is still not creating a good seal.  Any suggestions?  Does the fibreglass need to cure longer? Any assistance would be appreciated.

The fibreglass shouldn't feel tacky, I'm not sure what's going on there... there shouldn't be any need to do any sanding or cleaning with acetone or anything like that. It just does take more effort to seal tacky tape than simply applying it to the mould, you have to really go around it inch by inch, pressing and pulling and stretching it etc. If your thumbs don't hurt afterwards, you're either doing a very small mould or you didn't do enough pressing!

Can you post a picture of your setup?