I want to make a platform to help my son learn how to swim. I will sit in the pool when we are practicing and be removed when we are done. They have one at the swim school where my sons goes and he really likes it. It's basically made from 1 1/4" sch 40 PVC and has a platform on it. I think the one at school is metal with a rubber mat on it.. I have contructed mine already with just the frame with PVC ans some Stainless steel nuts & bolts. I want to know for the platform, can i just use a piece of plywood, either painted or with some kind of sealer that want harm my pool or kids. this will probably be in the water a few hours a week and i don't care about replacing it every year if need be. I saw some plastic boards that i could use as a platform at Tap plastic that is 1/2" thick but it costs about $13 a sq foot and my project is 20sq. $260...no thanks.