How about full length seam gaps?
For that seam in pic since its already on frame, dust paste would work. Going to take a bit of paste and will show but better to fill than to have your resin keep pouring through. Another option is glue and dust. Unless he wants to cut 1/8" strips out along those seams and fill with new wood which it would take a good amount of time. A lot of wood board issues pertain to regular woodwork issues. Researching ways to fill holes and cracks on web provides a lot of good info.
Just for clarity there was no gap here, the wood was tight together and sealed but edges butted together were chamfered, giving a lengthwise groove in the board.
I filled it with resin and sanded flush, there was nowhere for it to drip through.
My impression was this was your first glass job. My first glass job was in 1985. The whole point of my constructive consideration for you is that gaps, divots, or essentially anything not faired smoothly has the potential for trapping air whilst hand glassing your board. The picture I posted and only had reference to has a potential area for an air pocket with glassing. I don't understand the wood working terms you use but understand the intent. I hope you understand the purpose for not having divots under a hand glass job. Can't wait to see the result. Stoked for you!!
I get that and I'm hugely appreciative of the constructive comments, I replied about the seams because someone mentioned resin pouring through the gap and it occurred to me that from the pictures it may have looked like there was an actual gap between the planks that resin would pour through into the hollow part of the board.
I understand what you are saying about not having divots/grooves or other places where air pockets could form under the laminate, to this end I used a plastic syringe (I work in a lab) to lay a bead of resin down the groove between the planks and sanded flush, I'm sure it's not the best way I could have done it (could have thickened up the resin with some chopped up glass roving) but I am not displeased with how it's come out.
I am also stoked, it's a far from perfect project but I'm looking forward to getting it wet!
After filling the seam gaps I did another sealer coat with epoxy thinned with a little methylated spirits, and then glassed over the top. Quite pleased with how it went, the cedar deck looks good under the resin, my freelaps were better this time but still not the neatest so it will require some sanding again before the hot coat.
I was tempted to only do the hot/fill coat and not bother with a gloss coat, does anyone have any experience with this? I think in terms of strength my construction should be fairly solid already and I don't mind leaving it matte rather than polishing to a gloss finish.
If I just do the one hot/fill coat I guess I should install the FCS plugs directly after the laminate coat and leash plug after the hot/fill coat?
When it comes to venting, is there a good reason why I shouldn't I stall a car type inner tube valve into the board? It'd be tool less to equalise pressure and can have the valve core removed leaving a hole for long car journeys or storage.
Thanks again for all help or constructive criticism.
The finish is your own choice, no right or wrong anwer, gloss or matte. Myself, I would want a vent that activates with pressure, vs one that has to be manually activated.
"It still will happen, from time to time, this magic moment, when you're out with only a few friends..." - G. Rainfray