Melting GRP?

[Guest]

I'm about to start drying out the water saturated ballast void and the lower hull in my 1989 Colvic Watson MS (don't ask - its a long story). I plan to blow air from a Munters sorbent wheel dehumidifier into the ballast void and through the steel ballast from one end tothe other, to dry first the 1.5 tons of steel balllast and then the hull GRP. The air out of this type of dehumidifier is very dry and quite warm. Any suggestions as to the maximimum temperature that it is wise to expose a GRP hull to, before it melts or is otherwise affected? I can arrange for the air to be cooled before entering the hull keel void, but need to know the limits.

 

[jfkal]

Anyhting below 80 centigrade should be okay and sufficient to help dry

 

[Avocet]

80 Centigrade is OK for car bodies made from top quality heat-resistant resins but I don't know what they'd have used for the bottom of a Colvic - particularly on the inner layers that aren't (supposed to be) exposed to water. I'd try a maximum of 50 Centigrade and see what happens after a few days.

 

[oldharry]

Basically, you do not want to allow the hull to get hotter than you can bear with the back of your hand for five seconds. That is around 60C. It gives a good margin of reserve before you risk damaging the hull at probably around 70-80c. That would be hot enough to be painful and cause reddning of the skin and a minor burn. Be careful if you are blowing through the ballast not to create hot spots where the heat is not being carried away from the hull quickly enough. You would probably be able to tell from outside if a hot spot is developing (depending on the thickness of the grp), again by running the back of your hand (which is much more heat sensitive) over the hull exterior.