Originally written by flatlandfilly on 2010-09-11 11:34 PM
. How quickly does the roof weaken when the gel coat starts to come off? Thanks. It depends on several factors. The thickness of the gel coating and the layup will depend on the manufacturer's construction techniques. The quality of the gel and laminate will depend on the materials he used. The thicker and better the quality of the gel coating, the longer it will last. We used to coat with a 30 mm layer of Iso resins and had little UV problems. Once the gel is effectively degraded, has oxidized and washed off, the laminate is vulnerable to the same UV damage. This can be observed when the surface coating is no longer smooth, and a layer of fiberglass mat or cloth is exposed and visable. Unfortunately, laminating resin has little resistance to UV damage, and in weight saving measures and strength considerations, just enough is used to support the glass fiber matrix. It will be quickly damaged, and in doing so, will offer less and less support to the fibers. This results in an overall weakening of the glass panel, with a noticeable increase in flexation and possible cracking. Once this happens, the only recourse is to replace the panel, or over coat it with more glass and resin. Your answer about time can't be easily given. It depends on where you live and how much exposure the trailer has to the sun. Is it stored under cover? Is it subject to freezing and thawing? Again, construction considerations vary. It may last only a few years with no damage or a decade or so with little problems. It's easy to tell if there is any damage. Wet your finger and rub it on the fiberglass surface. If there is a powder transfer to your finger, it has suffered some UV damage. The amount that is removed and how much resin remains, is what will determine the roof's longevity. Painting is the easiest and most effective way to stop any further damage if the structure is still strong. This is a common practise in the marine industry. The other restoration recourse is to apply more resin and possibly some laminate, sand the lot smooth and polish. This is expensive and labour intensive. |