Thursday, October 6, 2011

Osmosis not just for cells and hulls

We finally have a better idea as to what is going on with our decks.  As originally suspected, and after discussing this with numerous people on the forums and through deductive reasoning we have come to the conclusion that it is, in fact, osmotic blistering.  This only makes sense if you look at all of the symptons:

1)  When we pulled up the old Plasteak, 90% of the glue holding it down had failed.  Coincidentally enough, the areas where the glue adhered best tended to read lowest on the moisture meter.

Notice glue adhere to the left panel and not the right

2)  There are clearly defined lines of crazing in the gel coat corresponding to with the seams of the original teak decking.

3)  We have found several areas of de-lamination, between the top layer of chopped strand mat and woven substrate, that also correspond to the areas where the seams failed.  In these areas areas, there is clear discoloration underneath the failed gelcoat.

4) After puncturing these sections of discoloration/blisters, we have also found that they contain osmotic fluid, which is easily identified by its strong, sour smell.  Kind of a dead giveaway from here....

This happened, more than likely, when the seams on the original teak decking failed and were not re-caulked quickly enough allowing water to remain trapped against the surface of the decks.  This is often times a common problem on the underwater portion of sailboat hulls, and is rarely found on the decks.  Lucky us...:(  The next step is to remove all the gel coat and areas of delamination and  allow it to dry, from what we understand, this could take anywhere from a couple months to a year.  Our plan is to closely monitor the drying using a moisture meter and marking out the readings in a grid pattern on the deck.  Once it's dry enough, we can proceed to fairing, barrier coating, and repainting.  I can't wait!

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