Using heat and sunlight to speed up epoxy cure

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Using heat and sunlight to speed up epoxy cure

Post by jem » Sat Mar 26, 2005 12:42 pm

Heat speeds up the cure rate of epoxy. If you're in hurry to work on your boat, this can be used to your advantage. But a word of caution for RAKA epoxy users:

Don't put your hull coated with fresh epoxy into direct sunlight until after the wet epoxy cures and is only tacky to the touch. On more than one occasion, I've found RAKA (their least type expensive resin) out-gasses as it cured. Putting it in the sun speeds this process and intensifies the gassing and it forms bubbles.

When in direct sunlight, the epoxy cures to form a "skin" (kinda like making pudding on the stove) but the skin is pliable enough to change shape. The gas builds and forms a bubble that does not pop unless you check it periodically as it cures and pop it yourself. Not sure the reason for this happening. Maybe UV rays effect one element of the epoxy more than another. I have not had this happen with raised temperature alone. Just when in direct sunlight.

I like to use the sun to my advantage but have learned to let the epoxy cure and out-gas for a couple hours in the shade (or indoors) before moving to the sun. Best bet sometimes is just to keep it in the shade or indoors and wait the extra time for cure. A very minor issue and does not factor into any "quality perception" of the RAKA brand. This would be an issue if one was in production and needed to prodcue the hulls quickly but for the home builder, doesn't really matter.

I have not tried this with any other brand so I don't know how common an issue it is.
-Matt. Designer.

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