> Ian:

> I enjoy your posts and appreciate the info and ideas. I've been a
> proponent for the use of silicone sealant as a gasket substitute in flush
> hatches, but it's really the idea that's important. So it sounds as if
> urethane would be a better mat'l?

> So:

> How is it applied? at home? with a caulk gun? from hardware stores?(maybe
> I should look more closely)

> Is it soft or hard, elastic, sounds as if fairly durable

> Is there a release for it? ie plastic wrap or vaseline for silicone?

> -mike

The urethanes I am using are a two component product that start as a liquid and then harden to a rubber like material.(The soles of many shoes are urethane) The product has a thick consistancy like silicon when dispensed, and do not shrink when curing.

They use a gun designed for the cartridge that is like a small caulking gun. They are also available in smaller self dispensing cartridges and are perfect for repair kits. They have a one year shelf life if unused so rotate your supply.

The great thing about urethanes is that they can be formulated to meet any need. So the answere to your question is "Yes". They are soft, hard, elastic and much more. You pick the product that suits your needs but as they are all urethane any one will work. So I could use the flexible one to fix a hole in my fiberglass boat. The repair is just as strong but the urethane is slightly flexible. You can choose from a wide variety of working times to suit your needs. Longer for deck to hull line up or shorter for foot brace instalation.

They can also be cast into a mould although I have not tried this. I don't know what you would use as a release agent but can easily find out. I had not thought of using it for hatch seals but it should work well.

They have several other products too, expanding foam, seam sealers, etc. All urethanes.

Duramix has training videos available if you can find a supplier in your area. These will show you how strong it is. Duramix is available from autobody supply stores. 3M also has similar stuff that they have just released, as does Dominion Sure Seal. I have tried all of these and find the duramix easiest and the most versatile.

Hope this helps. Ian