Hi All ;
I have just finished repairing the gelcoat on my fiberglass sea-kayak and
am looking for a clear-gloss varnish to cover it with. I did some
searching and came up with a couple of ideas, Interlux Super Spar 90 or
Z-Spar. I looked up Z-spar page and it said "not to be used below the
water line", so do I need to worry about this? What is your preference?
Thanks in advance.
Bill

"B. Comegys" wrote...

I looked up Z-spar page and it said "not to be used below the
water line", so do I need to worry about this? What is your preference?

The waterline reference is for boats kept in the water. There is no problem
using it on the hulls of boats kept out of the water between uses. Wooden
boat builders use it all the time.

I use Z-Spar Flagship, because it has better UV protection for my
epoxy-over-wood kayak. If you don't need the additional UV protection,
Z-Spar Captain is very popular.

B. Comegys wrote:

Hi All ;
I have just finished repairing the gelcoat on my fiberglass sea-kayak and
am looking for a clear-gloss varnish to cover it with. I did some
searching and came up with a couple of ideas, Interlux Super Spar 90 or
Z-Spar. I looked up Z-spar page and it said "not to be used below the
water line", so do I need to worry about this? What is your preference?

Why would you varnish a fiberglass boat?

Gelcoat is meant to be the outermost surface on fiberglass boats and
function as a sacrificial layer. You can buff it to a high gloss, just
like a factory finish. I don't know of a single production boat that
uses any kind of finish over the gelcoat. Varnishing would give the hull
a yellowish cast and make repairing the finish much more difficult,
without providing any benefits.

Varnish is used on wood boats to seal the wood. It's used on
wood/fiberglass boats to protect the epoxy from UV exposure. Neither of
these is necessary on a fiberglass boat with gelcoat. I strongly suggest
that you don't apply anything over your gelcoat.