gel coat on new construction

[Thomas Williamson]

We are near the completion of my 18ft Simmons Sea Skiff are ready to start painting. Does anyone out there have any thoughts on the advantages or disadvantages of having a fiberglass gel coat applied to the boat in lieu of a normal paint job?

Thomas

[TimothyB]

Woot! Can O worms time ;)

There is a fella who makes big, Pacific dories that uses thick gel coat on his bottoms and sheers to protect them from the dragging they get every day they are being launched from the beach. Say anything you want about it, a FG gel coat can be purty darn tough, all things considered.

That being said, unless the wood you use in the boat is top quality and stabilized, as well as encapsulated, using gel coat could get you into serious rot trouble sooner rather than later.

I'm sure someone here will remember that fella's name, or the article I am referring to about the beach launched fishercraft on the west coast made of wood...once that name pops up, you could talk to him about how he does it.

--T

[John Blazy]

A true gel coat is near 100% solids polyester, post-catylized coating of very high viscosity. Not only does Polyester not adhere as well as good paint, its shrinkage over time will create high shear stress at any thickness over 15-20 mils and peel right off the hull, no matter what the substrate. Gel coats are used in plastic boats because the gelcoat backer and chopped glass/PE resin layers are melted into the gelcoat before it fully cures (hence 'gel' coat) creating a high chemical bond. Not so with bonding to wood or any fully set up surface.

Something out there might be formulated just for this though, like a primer, but thats what high performance bottom paint is all about.

[John Blazy]

The reason they developed epoxy for boatbuilding is because it has higher adhesion to wood, much less shringage (reason for higher adhesion), and superior water resistance than PE gelcoats.
Just use epoxy - little higher cost, much higher performance.

[Thomas Williamson]

Timothy,

Is that the Pacific Coast Dory that is used a lot up in Oregon? I have that issue somewhere. Wonder if I can find it?.....

[ 10-15-2003, 12:35 PM: Message edited by: Thomas Williamson ]

[Concordia..41]

FWIW at his seminar at the 2002 WBS Giffy Full expressed that Awlgrip on a wood boat caused problems because it created a solid barrier and didn't let the wood breath enough. He explained it better and had several examples, so if you follow that reasoning, gel coat certainly wouldn't be a good idea - adhesion problems not withstanding.

[TimothyB]

Originally posted by Thomas Williamson:
Timothy,

Is that the Pacific Coast Dory that is used a lot up in Oregon? I have that issue somewhere. Wonder if I can find it?.....I think that's the one yes! With the random color schemes (I remember he lets his painter choose colors), high bow and plywood hulls.

I remember very vividly that he puts gel coat on his boats' bottoms for 'toughness'. He may have a process for it that takes care of the usual concerns.

--T

[Russell Sova]

Refer to R.J.'s thread of a few days ago. He asked how to remove fiberglass resin. How can this polyester resin be as bad as some say it is if it can only be removed at great effort with a heat gun?