Sunday, November 18, 2007

Starting float outside laminations

It is time to start the propane heater if I am going to do any laminating in November.

The float has been sanded, filled,sanded, much as I can. It is as prepared as I can make it.

I have decided to follow the following strategy for laminating the float exteriors.

  1. Lay the first layer of the 8.9 oz 7781 cloth down. The bolt is 50 inches wide so I will be running a number of widths down the length of the hull. This allows the finished edges to run vertically up the hull.
  2. I require to lay two layers of the cloth to make the specification of 16-18oz fiberglass weight. This gives me an opportunity to offset each layer 3" down the length of the hull and have only two layers of cloth everywhere. No need for rebates to compensate for extra layers of fiberglass.

Getting the two layers of cloth wetted out and lying smooth is always the hardest work. Here I have just laid out the second layer of style 7781 e-glass cloth.

After smoothing out the plastic on the peel ply I used masking tape to hold the edges of the plastic over the gunwale, keel and bow tight curves.

The temperature is about zero outside but on the plastic it looks like it is almost 15 degrees celcius. Warm enough for epoxy to cure.

Seven hours later the resin has cured sufficiently to relese the plastic. It just lifts off , no pulling or peeling, leaving a very smooth glossy peel ply and laminate. This technique certainly saturates the peel ply with excess resin.
I'll update when the peel ply comes off. I had planned to go farther down the hull in this work session. But as the fates have it I ran out of peel ply. So, if it looks as good with the peel ply off I'll be full speed ahead when I get more supplies.

Pictures with the peel ply off. Superb adhesion with no air bubbles causing the cloth to lift. There are still areas that are a bit dry. I am not expert enough to know if this is a problem.


biol said...

Hi Grant, nice job !
I'm not sure I understood your glassing strategy, if your 7781 cloth is BD. If you do not overlap 3" on each single layer, there will be vertical lines on your finished float with only one countinuous horizontal glass filament under ... will it be strong enough ?
This "no overlap" way would works with 2 layers of 300 UNI glass, IMHO, one lenghtwise and the other rotated 90°. Is your 7781 a UNI cloth ?

Ciao !

Biol (who should try to sleep at 4 am, instead of browsing the net)

GK said...

Hi Biol,
The 7781 style cloth is a loose 8HS weave and is completely bi-directional. It has 57 x 54 strands per inch of weave. Information on the style is at the manufacturers site.

I'll think about your other comment.

Good night Biol.