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pirateofcapeann 05-25-2003 03:31 PM

Glassing Question
 
As a wooden boat owner Iíve got to admit that the ratio between the time spent maintaining the boat and the time spent sailing the boat isnít what I had envisioned.

One project Iím up to my elbows in is replacing the canvas covering the cabin top and hatches. This is the second time Iíve had to do this job and I donít ever want to do it ever again. For this reason Iíve decided to use fiberglass instead of canvas. I got the idea from the owner of a beautiful Concordia who has done this to his cabin top.

The plan, which is well along, is to fair everything up and lay down a layer of 10 oz. cloth, stapled taut with S/S T50s then wetted out with polyester resin. Unfortunately Iím getting some mixed messages about part of this process. One tells me to bond the glass to the wood to keep moisture out another says to not allow the bond so that the wood can swell and contract without damaging the glass. Right now, Iím leaning towards using a mold release on the wood.

The weather here in the North East is calling for rain over the next few days so Iíve got some time to solve this question before the glass is laid down. Any suggestions would be appreciated.

Jeff_H 05-26-2003 06:52 AM

Glassing Question
 
Here is my answer based on the time when I owned wooden boats. In the 1970''s and 1980''s I owned a Folkboat and later a 1939 Stadel cutter. Based on my experience, expecially with the Stadel cutter which we kept in Sarasota, Florida I cannot discourage you strongly enough to avoid using polyester resin for the project that you are considering. That is a very short term solution that will be even shorter term if you float the deck over mold wax. The only way that that could work would be to build up enough thickness in the polyester/glass that the polyester and glass formed an indendent structure. That would probably require a layup schedule with a layer of roving, a layer of mat and a layer of cloth. That will add a lot of weight, cost and labor.

The best results that we achieved in replacing deck coverings was by sanding the substrate down to bare wood (in our case we had different species of wood to contend with which included sections that were teak, cedar, and fir plywood.) We then replaced any dubious fastenings and repaired any rot that we encountered. We then sealed the exposed surface with several coats of epoxy resin to reduce movement. After sanding the sealed wood, we came over the top with a layer of fiberglass cloth in epoxy resin. Where we had fairing to do, this was done over the cloth using reinforced (short strand fiberglass) epoxy resin. Where we had more than a glazing thickness to fair we laid either another layer of cloth or a mat like material that was made for epoxy but which I understand no longer is made. When all the fairing was completely we rolled out several layers of epoxy and then primed the decks and painted them with a high grade alkyd paint. The few areas that we did in Polyester lasted an extremely short time compared to the sections that were done in epoxy which still looked new when we sold the boat quite a few years later.

Jeff

pirateofcapeann 05-26-2003 05:30 PM

Glassing Question
 
Thanks Jeff. I was hoping you''d get in on this one. I''m going to take your answer under advisement and shift my plans accordingly. I was hoping to not make an investment in Gougeon Bros. but if it will get the job done and final...

I''m wondering if the mat like material you refer to isnít "dynel". The decks and cabin top of my father-in-law''s 44 footer was all done over in it and they have held up very well for at least 15 years. Unfortunately, I can''t seam to source out any.

Oh, by the way, there''s a blurb on the folkboat Eira in Sail this month, if you get a look.

paulk 05-26-2003 06:04 PM

Glassing Question
 
As Jeff says, epoxy resin is the way to go. Fiberglass resin won''t adhere well enough to the wood to make it long-term. If you are worried about the wood "breathing",or allowing moisture in the wood to escape, leave the inside unepoxied. Check on the Woodenboat site as well. They''ve had many aricles over the years on redoing decks the way Jeff describes, and someone will likely be able to provide leads for dynel. (They have a separate forum just for finding suppliers.)

VIEXILE 05-27-2003 01:54 PM

Glassing Question
 
See the text "Fiberglassing Wooden Boats" or some such thing. The gentleman is in Mattapoisett, MA, as I recall. Has to be done right, but I believe he was using regular resins. The key was appropriate mechanical attachment, scarfing for butt ends and layup.

paulk 05-28-2003 07:27 PM

Glassing Question
 
Believe that Alan Vaitses'' book, "Fiberglassing Wooden Boats" was written before the development or widespread acceptance of epoxy resins - perhaps in the mid 1960''s. My father fiberglassed over our Cape Cod Knockabout using essentially this method. It just about doubled the displacement of the boat. It didn''t leak afterwards, but we couldn''t get it to move much in less than a full gale either.

Jeff_H 05-29-2003 02:58 AM

Glassing Question
 
Paul is right that Alan Vaitses'' book is way out of date. There are two problems with glassing the deck using polyester resin and counting on mechanical fastenings. First of all the glass needs to be thick enough to act as an independent structure rather than a simple sheathing and wearing surface, and second there is an area between the unattached fiberglass sheathing where moisture and air can exist which creates the perfect environment for rot to occur un abated. When I restored my folkboat in the 1970''s, the cockpit sole had been done that way by the previous owner only year or two before I bought the boat. By the time I bought the boat there was widespread rot not only in the original cedar sub decking but also in some new cypress planks that had been installed to replace some bad wood when the previous owner had glassed this deck. What ever you do you want the glass fully adhered and epoxy is the way to go on that.

Respectfully,
Jeff


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