Marc wrote:

I have discovered that I have wet core in several locations on my
cabin top. My limited experience with fiber glass has been with West
System Epoxies and I am comfortable with their use. The bottom skin
has been removed, the wet core excised and the top skin abraded and
prepped for bonding. I intend to wet out the underside of the top skin
and use Baltek Contour Kore AL600/10 to replace the core. After that
cures, I need to build up a bottom skin of at least 3/16". I need a
layup schedule that will give me max strength with the fewest number
of plies. This is a winter project. I will be able to maintain 40* in
the boat and intend on using the fast hardener. All suggestions are
welcome and hints as to technique or alternate methods are
appreciated.

Is that 40* Celcius ot Farenheit?

Look at the underglass surrounding your area.

One thin skin? Mine was. The shape is concave, an archway that does
not depend on tension for support.

Try building a bench or support up under the application, a foot
below it. Consider a plastic or disposable drop cloth or papers.
Lay out a prepared plastic garbage bag under target area. Lay out
wetted glass on bag, resin dipped or poured, and wet brushed
overhead. Inflate bag.

Use as much glass as you think you need. One or two scrims aught to
to it. You could level it all under with peanut butter mix first,
but does it matter much, overhead in the wet locker? Catch drips.
Heat outside, too, with plastic bag tube with small vent filled by a
little heater fan? A vacuum cleaner exhaust should do it.

Maintain pressure until cured. It may be possible to seal the bag
and stop the fan. Air pressure in the bag should then push the
glass up to cure.

You may want to add a little thickener.

If you use a clear bag, you may see any bubbles trapped between top
and cloth. You might sweep them out with a soft bag and extra hands.
Good game of twisters, what?

You can feed the air through a tube made from plastic film and duct
tape, or a plastic bag pulled through a bisected "goose strangler"
beer can tether or two, or dryer vent. A twist tie will leak after a
while, so maintain pumping capacity (inhale!) until cured or tacky
enough to press up geotex, cloth or paper. This would be a good time
to properly dispose of the orphan beers. You can paint fuzzy geotex
any colour, but you may be happier with burlap, or some safer finish
coating, even simply paint, considering fire and fumes.

You could constrain the inflated shape with a piece of tape or
fishnet laced to whatever shape you need. If you surround the bag
with net, lay it out and cover it with waxed paper taped together
securely before you lay out the glass and proceed with pumping.

Try a dry run with wet newspaper simulating the weight. The bag may
push sideways when filling. Find and eliminate pokey hole makers, or
protect with a wad of tape.

I tore up my topsides, portside. Let us know how you do. I am
pondering the starbord side. There's a lot of stuff in the way under
the side decks!

Terry K