Glass layers/sanding

Hello everyone. I am building an 18' dory skiff with my father in law (first build for us) and have applied the first layer of glass. This took most of the day and i think it turned out pretty nice. I have a bad back, so i am limited to 6-8 hrs of being upright before i lock up. There is no way we could have applied the second layer of glass before the first was too far along in the curing process. I needed to stay off my feet the next day. I know we should have applied both within 24 hrs to get that chemical bond. I also know that we can still apply the second coat but we need to prep and sand. Do we sand the hell of it as much as possible and get it as smooth as a babys bottom without getting into the glass or do we just scuff the surface. I want to do it right, but dont want to go overboard if i dont have to. Thanks all.


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RE: Glass layers/sanding

According to System Three, their epoxy can go 3 days before it needs sanding for the next layer. You should check the recommendation from your epoxy manufacturer, you may be OK to just apply the next layer.

If you do sand, just scuff it up. You're only trying to increase the surface area so that the top layer has more to bond to.

If when you start sanding the paper gets clogged and you get gummy balls of epoxy, it hasn't finished curing and you can skip the sanding and move directly to applying the next layer.


RE: Glass layers/sanding

   Thanks Laszlo. The epoxy has cured. Its been a week since we applied the first layer. There are a few spots where the cured epoxy is thicker so i was wondering if those areas needed to be sanded to the same level as the surrounding epoxy. Its about 1/16" to 1/8" higher in spots. All of the areas are on the bottom of the boat and its going to be painted. Im trying to get out of sanding this rock hard epoxy that much if i dont have to. Hoping to get by with scuffing instead. Especially since its the bottom of the boat and not visible.

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