Team Seacats

This is actually the second iteration of testing the vacuum bag setup on one of the two molds. I first tried using rope caulk around the perimeter but I found it difficult to get the pleats in the bag to seal well. The pleats are necessary because of the concavity of the mold – it needs more plastic to fit. I found great success and relative ease by running a strip of masking tape along the entire perimeter of the bag and then pleating it by sticking the tape to itself in strategic areas. Initially, I didn’t think the pleat position really mattered and I placed them all right in the middle of each side. I found that both the bow and the stern were having trouble conforming because of their distance from those pleats. What you see here is two smaller pleats nearest the bow and two large pleats nearest the stern (and naturally, two large ones in the middle of either end). I was able to get -20 in/hg with this setup…and that’s all my venturi vacuum generator can create … it’s more than enough for vacuum bagging this lamination.

The only drawback to the tape method is that it is still going to be tricky to use with PVA on the mold – I will not be able to reposition the tape once it is adhered because it will lift the PVA covering the sticky side of the tape if I do.  Of course, I still had the same problem with the rope caulk around the perimeter.  I may try to mask off the outer edge of the mold to keep the PVA from getting in there.

Sizing the plastic sheet also proved to be important.  I took a piece of strong and measured the length of the surface of the mold and the width (pushing the string down into the cavities).  It ended up with almost exactly 4″ of extra width and length due to the shape of the mold…for a perfect fit.  I added an extra 4″ and the plastic sheet is 20″ X 56″ (this blog serves as my records too!).  I’m now working on the templates from which to cut the glass cloth.