Builders' Forum Archives
Re: Stupid question.....
Posted by LeeG on Mar 28, 2005
A few ways. One is that it's in the air of your shop. You may not think it's much but it's there. Close that compartment up and temperature changes will condense/evaporate what little water vapor is in the air. When one side of the bulkhead has no pressure differential with the outside air and the other side does then one side is going to have water vapor(no matter how small) along with air attempt to find release. Whether the watervapor in a closed compartment from your garage is enough to start the black ick I don't know. The amount you'll get at the waters edge is. If you do not put in a small hole to equalize the air pressure there will be a significant change in pressure when you drop a warm kayak onto cold water. The very first Pax20 prototype was well sealed,,it's the one without the kingplank in the photos. It was placed on relatively warm water of the South River and the pressure drop imploded a dime sized hole in the 3mm deck forward of the bulkhead. But just for arguments sake let's say the deck doesn't buckle in, let's say you didn't put in a pin hole. Let's say you put the kayak in the water. SOMEWHERE in all those various parts of the deck/bulkead there will be a constant vacuum looking for release. Let's say you didn't do a stellar job sealing the underside of the deck, maybe it'll transpire right through the deck up and over the bulkhead? You know those outgassing bubbles that can develop if you put epoxy on warming wood? Ok,,those are very, very tiny holes. And eventually the pressure does equalize. Eventually a relative pressure difference in the compartment that isn't expressed by a puckered deck will occure somewhere. Once you put vapor pressure differences the vapor will find a way unlike the pressure of water simply sitting in an epoxied compartment. I think the confusing part is that you aren't taking into account the huge range of temperatures the compartments will go through and what that does for condensing water. Imagine leaving a tuna sandwich in your car when it's 60 degrees then the day warms up with the inside of the car getting to 100. Wrapped up in plastic wrapper you'll still smell the tuna. Leave it in for a few months and you'll really smell the tuna.
In Response to: Re: Stupid question..... by George K on Mar 28, 2005