maandag 10 december 2007

First exterior laminate

Cabin side + gunwale area + part of deck are laminated with plastic on top. On the deck I made a rabbet with the electric planer as this is supposed to ease the fairing of the overlap of the cloth. Although I'm not really convinced it is necessary in this spot (deck will need a lot of fairing anyway because of the extra layers glass) it's not a lot of work on a flat surface like the deck, so I decided to go along.

Here is the laminate with plastic in place....
...and here the plastic is removed. The 'plastic without peelply-technique' results in a very smooth shiny surface with the weave of the cloth filled. It's not difficult to sand it 'dull' without sanding (too much) in the fibres.
Lesson learned: don't try to 'plastic' multiple-curved surfaces with one big sheet of plastic, or you'll mainly be busy trying to get rid of creases. The creases fill up with epoxy, leaving a ridge after removing the plastic. It's much easier to work with overlapping 70 cm wide pieces of plastic. Luckily it'ts easy to remove the ridge.
I'm happy using the 'plastic' technique (not a single bubble this time), although like with most things it takes some practice.
Some lessons learned the hard way:
    • It's still important to wet out and smooth out the cloth as well
      as you can before putting on the plastic: with the plastic on it's easy to get rid of small imperfections and air-bubbles and excess resin, but NOT to shift the cloth in a major way, and
    • I hoped it would be possible to use the 'dry-method' with plastic, but that didn't work. On the spots I didn't pre-wet I still had a hard time to get the cloth well adhered to the foam: it just doesn't tack to the foam right away on all spots, and adding more epoxy is of no use. Does this sound familiar to other builders using divinycell? On spots with putty/ply I don't experience this problem. So it's obvious: I should build a ply stich&glue boat!
      Now serious: I'm planning to see if it helps to coat the foam with a thin layer of epoxy and let it cure before laminating so I can use the 'dry method' for the lower hull half exterior.

1 opmerking:

Grant zei

I'm convinced that the divinycell (maybe corecell as well) especially after fairing has a significant surface roughness that requires an appropriate amount of epoxy to fill. So I think you are correct in that a thin coating of something lighter than epoxy (a light filler) will help to get the laminate wetted out in a dry application.