Some things to consider:
- Resin strength- The resin used is a big factor. Ortho, Iso(what I use), Vinylester, etc. If you need your board to be bright white then ortho is the only clear one mentioned. Vinylester is even stronger than Iso but has even more color to it. Iso and VE can be difficult to work with until you find the right product and get your system down. I only use polyester resin so that’s all I’m addressing here, epoxy experts are more qualified to talk about those.
2. The order that different weights of glass are stacked- I believe that having larger weave against the foam is less likely to delam and tighter weave on the outside is less likely to get surface cracks. An example would be on a 6+4 glass job having the 6oz on the bottom and 4oz on the top. I know this flies in the face of convention.
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Match top and bottom glass schedule- The standard is to glass the deck heavier than the bottom since the deck gets all the abuse from body contact. Unfortunately when the flex and strength don’t match on the top and bottom it’s more likely to result in a broken board. I’ve set up my current glassing schedules with this in mind.
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Choice of weave- E, S-cloth, flat weave, etc. A big subject when considering weight/strength ratio.
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Avoid unreinforced resin- Excessive hotcoats and gloss coats that aren’t sanded tight will increase the chances of surface cracks. Note that cracks starting on the surface will always find there way through the weave and to the foam, often broken boards start that way.
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Sealing- Sealing the blank makes for a better bond to the foam by reducing the chance of a plural space developing between the foam and glass as the resin soaks into the foam during the drying process, especially when tight weave (ie: 4oz or flat weave) is used next to the foam. With proper application sealing shouldn’t add weight and net resin use should remain the same since sealed blanks require less resin to lam. Note that squeegee technique and faster cure times are are always big factors to achieve a good bond, especially if the blank isn’t sealed.
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Several of these items I’ve never heard discussed but seem obvious to me after experimenting and observing. The extra steps are outside of the industry standard and not practical in production glassing. Just things to think about if your looking to make a stronger board at any given weight.