The Rot Doctor


Subject: delamination from core
Date: Tue, 20 Apr 1999

Sir, I have a vessel (glass) that around one hatch water has penetrated the plywood lifting the glass off of it. I had thought that it might be possible to drill in about the center of the area,apply the CPES then place a large weight on the spot to allow the glass to attach it self, I am not sure if the area is rotted I will check it with a moisture meter tomorrow. probing the area it feels just as if the glass has separated from the core.

Bert S.


Yes, this is easily done. In fact, I was looking at the cabin top of my own boat and saw that I'm going to have to do the same thing.

Check and see if the area that has delaminated is reasonably dry, as you suggest. Moisture meters are helpful but not absolute through fiberglass. If in doubt, prop a hair dryer into position and allow it to blow on low heat/high air for an hour or so.

After you are sure it is reasonably dry, inject CPES (Clear Penetrating Epoxy Sealer) into the area. Whether you need to drill or not depends on how deep the delamination goes. If not too deep and there is no large area of rot, the CPES will probably penetrate deeply enough by itself. If the delamination is deep and you suspect some bad wood may be in there, then drilling some CPES access holes might be appropriate.

Allow about a week for the CPES to cure. It sometimes takes this long on deep penetration because the carrier solvents have to have time to ventilate away. Next, depress the area with your weight and see if where it settles is going to be satisfactory. If it bulges too much you may need to remove some wood. When it's where you want it, you should then push in some of our All Wood Epoxy Glue. This is very strong and slow setting so you'll have time to work with it. After you get it in there then, as you suggest, weight it down for 24 hours. You can clean off excess glue with our Epoxy Solvent after you depress the area.

You're done. The plywood is protected and the glass will adhere to the wood forever. Come back if you have more questions.