Pat Russo wrote I generally use Styrofoam, (blueboard), applying a wet resin layer, then a slurry layer followed by fabric and stippling.... ending with a squeegeeing of excess resin
The whole idea of using slurry is to make the piece you are building weigh less. The glass balls (microspheres) take up space and weigh less than pure resin. The idea in the old days was for this mixture of resin and microspheres (slurry) to be as thick with microspheres as you could spread without tearing up the foam you were covering. The more microspheres that is added to resin the thicker it gets and the mixture weighs less but the slurry mixture can reach a point of being so thick that spreading it is almost impossible without tearing up your nicely sanded foam surface. The idea is to add as much microspheres as you can to the resin but still be able to spread it onto your foam without tearing up your foam of course! This mixture was developed to penetrate the pores of rigid urethane foam which is very porous and later the klegicel foams that are now used, thus less weight parts as compared to parts made with pure resin filling the pores of the foam. Step one should be the slurry mixture on the foam (if you use pure resin first you are filling the pores of the foam and making the part heavier) Step two add your cloth of choice Step three add only as much resin as it takes to wet out the cloth of choice. Any extra resin only makes the part heavier not stronger. If you are using insulation foam that has a nonporous solid surface, I would not recommend that foam but I am not totally sure what good the slurry is doing if it is nonporous foam. Just my opinion. Larry H. ________________________________
