Re: Glassing Question
assuming your using epoxy, but it mostly applies to polyester as well.....
as a general rule of thumb, you can go "wet on wet" with epoxy within 24 hours and still have a primary/chemical bond. But after 24 hours the epoxy normally pretty hard and mostly cured, so your bond will be mostly a secondary/mechanical bond - if the surface is slick/smooth, then there is isn't much for the next layer to latch on to
However, as the prior layer cures, the amount of primary bond available decreases as time goes on.
Another concern (with epoxy) is blush, if you using a resin that blushes then I always wipe down with solvent then rough it up.
It takes so little time to rough up a surface and ensure a good secondary bond, why not do it and be safe? Unless the previous layer is still soft/tacky, I always rough it up a bit.
Straight cabosil/silica for bedding or fillet putty can be a brittle - I would recommend using another filler with the cabosil/silica, something with fibers: cotton fibers, glass fibers,wood flour, etc
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