Saturday, April 30, 2011


I pondered long and hard about how I would glass this section.  Part of me wanted to 'go for broke' and do it all.  Luckily better judgement prevailed – the reality of doing all the steps for vacuum bagging by myself is daunting.

I decided to divide it into two sections.  The obvious choice was then to run the glass in vertical sections. (I had done this in the floats.)  Since you can't do the section in one piece anyway, it's not as if its overlap vs. no overlap.  When adding up the extra by going this method, and then calculating the weight of 3 inches of glass and epoxy -- it seemed like a small difference given the advantages I perceived.

I finished placing the foam along the gunwale.

The edge has a thin skim of fairing material to help the vacuum tape seal.  For the vertical seal I epoxied on some peel ply to ensure easy removal of the vacuum tape.

With all the changing angles the edges of the glass don't lay straight.  Multiple pieces almost seemed an advantage for keeping the average orientation of the glass in its proper direction.

I put down some plastic under the glass while moving it around to get the proper orientation.  This kept it from snagging, then the plastic was easily removed from underneath.

After protecting the vacuum tape with a layer of clear packaging tape I wet out the cloth then peel ply.

Perforated release film and then breather.

And then the bag.  If I hadn't had stretchy bag material I may have been in trouble without enough pleats.  More next time.

Also I had trouble with a large leak.  Fortunately, I was able to hear it when the vacuum was turned off.  It was from a screw that was set too far, but hadn't been found before hand.  I turned off the vacuum and removed the screw.  I replaced it with a bamboo skewer and 5 min epoxy.  Once cured, I was able to achieve my vacuum.  Whew.

Looks like the right amount of resin.  I've never put on so much resin that I think, "thats too much" (meaning its easy to keep adding too much). So its great to see excess weight removed.  Also, I would have been stressed about getting the glass to tightly conform to all the angles, corners, and vertical sections.  The beauty of vacuum.

Happy with the result.

For the stern section I discovered a couple of things.

In thinking about the overlap, I remembered that I only needed to overlap in one direction.  In this case the vertical tows only need to butt against each other.  It's the bow-stern tows that need to overlap.  By pulling out the unnecessary tows I decreased the excess by nearly 50%.

There's a reason that there are no more pictures of glassing the stern section – stress!

What I discovered was that the vertical portion was large enough that my materials didn't want to stay in place.  The glass was only marginally a problem, though it was a bit of a battle between getting it into the concave areas and pulling it up the vertical face. The vacuum would take care of that. The problem really was the non-sticky layers.

The breather wouldn't stay where it was supposed to.  Trying to make the bag around it . . . then the glass would fall too. What a struggle. It was after midnight – and I could tell I was near my wits end.  I called my wife who helped calm me down.  Then I remembered Henny using staples to hold material in place – and it saved the day.

Luckily I had 1/4 inch staples on hand and with my wife's help was able to hold things in place on the sacrificial foam that was to be cut off later.  The bag was made and disaster averted.

I would have liked to incorporate the unidirectional along the keel while doing the original layup, but dividing it into sections precluded that.  So that was the next step.

Stapler in action!

Next was the cabin top. I changed batten material and got clear fir.  I had used it on the gunwale because I wanted something stronger since I would be walking on it. It seemed to work well on the gentle curve of the cabin.  Also, I was planning on putting pieces of 3/4 inch foam that were as large as possible without thermoforming and didn't know how much deformation force to the battens that would be.

You can see the break at the front deck to cabin area.  I hadn't appreciated how this break was not straight athwart ships, but slightly curved, sticking forward more in the center.

Around this time I began to experiment with over drilling the battens.  Hadn't really though about it before, but by over drilling you can get a compressive force drawing the pieces together. Similar to a screw that is only threaded on the section that goes into the second material.  Working with 3/4 inch material was easy because of the great holding power – 3/8 is another story.

In the end it took quite a bit of pressure to curve the panel into place (as in laying on my back and pushing with my feet), so it was nice to have some help tighten the screws from the back side.

No comments: