Controlled Vacuum Infusion of mainhull bottom

I can say I now have a lot of experience with making airtight vacuum bags. As a matter of fact, within this project this is big hull vacuum bag number 9 and I thought it would be a piece of cake. After all, it is not just a vulnerable foam hull anymore but a foam hull with an airtight internal laminate. And the joins of the Port and Starboard halves are covered with a glass tape. So no worries about air tightness. I thought……….

Unfortunately that assumption proved to be very wrong. I did some stupid things, such as using temporary screws that were simply too long here and here. This area was also not airtight.

Furthermore, it seems there were air channels in the UD fibres running from the outside to the inside in the forward beam bulkhead flanges.

In short: it became a headache vacuum bag—actually the worst one I have ever made—and it took far too much time to get it under control. Because the infusion of the hull was already planned and I had appointments with helpers, I worked a continuous 40 hours to fix it. Still, the bag was not good enough to start the infusion. A disappointment for everyone, and I had to cancel the event.

Two weeks later it had to happen. After more changes—read: four 8’ extensions to gain clearance around the beam flanges—and further improvements to the hull’s vacuum integrity, we tried again.

Even though the third version of the vacuum bag was still not perfect, the infusion started at 3:00 PM. As usual, there was a lot of interest from colleagues and friends. A few precautions were taken so we could solve potential problems during the infusion, and that worked out satisfactorily.

Only the end result counts: despite the troublesome preparations it was again a success, a big relief, and another milestone in the project. After an evening and night watch during cure, I went home at 5:00 AM the next morning—tired, but with a good and happy feeling.