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Re: Cetol Marine Finish Woes
Bubbles can appear during the application of any coating on (POROUS) wood and whether brushed, sprayed, etc.
The usual 'cause/culprit' is SUNLIGHT and the heating of the wood surface which causes that portion of the coating that has partially penetrated to "OFF-GAS" ... and form bubbles. Once you laydown first coating which totally SEALS the natural porosity of the wood, rarely will you experience bubbles and no matter how much the sun heats the material. Its that FIRST thin coat that becomes WARMED/HOT before the coating fully sets/cures that is what causes bubbles.
The prevention: don t apply that first coat on a hot day or a day with lots of SUNLIGHT that will 'heat soak' the material under where the coating will be applied. First coats or thinned down 'spit coats' are best applied in the SHADE, and several 'spit coats' to ensure total sealing of the porosity. Once you fully SEAL the surface, then its time to lay on FULL THICK, wet coats.
Bubbles shouldnt be a problem but can cause a lot of needless extra work - resanding, filling the craters left by broken/sanded bubbles, etc. Better to put a shade over your work for the first few thinned down 'spit coats' and prevent this from happening. Even in the shade, you have to FEEL the surface temperture when applying first or spit coats .... and if that surface feel warm or HOT .... wait until a cooler time.
Last edited by RichH; 03-31-2014 at 04:40 PM.