Polyurethane sealant

[sfreihofer]

I am restoring a Cape Dory 25, #794, built in 1981. http://members.aol.com/sfreihofer/homepage.html.

I will be using a polyurethane sealant (like Life Caulk) for bedding hardware, but as with all things nautical, the price is daunting.

I also belong to a personal submarine mail-list, PSUBS.ORG. There has been discussion on that list about sealants, and some members swear by a polyurethane sealant called VULKEM 921, made by Piedmont Plastics, Inc. and available in cartridges for about $8.00. http://www.piedmontplastics.com/html/pr ... 1_-384.htm. It is used mainly in construction.

I find nothing in the Cape Dory archives referring to this sealant, but everything I've read indicates it is equivalent to Life Caulk, which is more like $18.00. Does anyone on this list have any knowledge or experience with Vulkem?

[The Patriot]

... I will be using a polyurethane sealant (like Life Caulk) for bedding hardware, but as with all things nautical, the price is daunting ... a polyurethane sealant called VULKEM 921 ... everything I've read indicates it is equivalent to Life Caulk ...

Life Caulk is a polysulphide sealant, not polyurethane. 3M 5200 is a polyurethane sealant. There is quite a difference. If you are able to check back issues of The Practical Sailor, you will find a number of review articles that give some very good detail on, and comparisons of, these materials.

[Cathy Monaghan]

I don't know anything about VULKEM 921 but polyurethane sealants like 3M 5200 should only be used for permanent installations. But there are different grades of polyurethane sealants for different purposes. Anyway, whatever you do, don't use 3M 5200 as a bedding compound on items that may need future removal.

CLICK HERE to read the data sheet for VULKEM 921. It may help you to decide if it's the right product for your application.

Hope this helps,
Cathy
CD32 Realization, #3
Rahway, NJ
Raritan Bay

[sfreihofer]

Ahhh... I'm glad I asked. Thanks for the clarification. I'll go with the high-priced spread....