> My reasons for doing it this way are as follows: 1) The soft
> 'mold' gasket must be bonded very firmly and rather precisely to the
> substrate to form a good cast. Since there is a gap between the hatch and
> the deck (1mm to 3mm) AND the gasket edge must be aligned with the deck
> opening this area will be very vulnerable when you force the epoxy putty
> around the edges (some may squeeze through and fill the gap or distort the
> soft foam. BAD).

Hi Vaclav

I haven't done it, so have the benefit of ignorance, but:

The first problem may be using something soft to make the mold. What about some harder rubber trim, or hi density styro, or multiple layers(vertical) of card, or wax, or plaster, or plasticene, or that stuff that kids use to make sculpture and hardens, or clay.

The deck-hatch gap in this point and your point three can be closed by plasticene, drip candle wax in, rub candle across gap, or rub in soap, or use oil clay.

> Second: I found out that the trim waste from the deck portion of the
> gasket makes up about 30% of the final product weight. This is just dead
> weight if you leave it in place. It can be reduced a bit by careful layup
> but if you have three rims to lay-up in one afternoon and the epoxy is
> setting on you, there is no time to mess around.

Can't really respond to this - careful layup, I guess.

However:

I think you're doing it upside down. The gasket on the deck flange is vulnerable to damage every time you put stuff in or open the hatch. (I know this cause it's always hard to quickly hide the chainsaw after clearing some real estate for my tent. Them annoying trees!) And the upturn flange. Doesn't it alway have some sand and grit caught in it. And isn't it just too hard to clean down in those gaps betw the upstand and the gasket and the gasket and the deck? And when you cinch down the hatch cover, doesnt it deform a bit at the attachm't locations.

So glue the gasket on the hatch. Then rarely gets damaged, easy to clean, easy to repair in the tent.

Eliminate the upturn on the flange. Then this area won't catch dirt, sand.

1/ If you like downturns, put a downturn beside the gasket on the hatch. This will encapsulate only one side of the gasket thereby placing force against the deck edge as well as the flange giving a better seal. The downturn also stiffens the hatch thereby giving a more uniform clamping pressure around the perimeter or the gasket.

2/ If you wish to make it more structural for your kayak, and easier to place - make the downturn say 3/4in deep. Obviously stiffer for the hatch, but the larger downturn and hatch edge will allow the major compressive forces along the top of the yak more easily pass thru this area esp if your hatch is held down w/ bungees as in some here. Like from pounding out thru surf, or pearling on the sand on the ride in. The other advantage is that it self ctrs as you put the hatch in. (Hey - prob makes a good salad bowl too!)

-mick