Join Date: Sep 2007
Location: North Florida
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If you don't want to go the acrylic or polycarb route, laminated saftey glass will work just fine.
As John mentioned, the fogging is likely caused by moisture wicking between the two layers of glass and delaminating the pane. I think MaineSail mentioned it, but I read somewhere that polysulphide sealants actually assist in this process by breaking down the bond between tha panes.
So, an ounce of prevention has been my approach. I have replaced/am replacing all six of my oval portlight panes (same problem), and I'm sealing the edges with two coats of unthickened epoxy. I taped the glass to prevent getting epoxy on the front/rear of the panes, using 3M 2090 painters tape.
Hope this helps,