You might want to consider a coat of Behr exterior acrylic concrete/tile sealer over your final fill coat of epoxy to seal/fill any epoxy pinholes that might create leaks through your paper skin.
Behr acylic is great stuff.
I am printing out the lattice for my board right now. I’m thinking I may take a crack at the polyspan route, which should add some real good puncture resistance. Unsure how well that will bond to the PETG, and the glass for that matter. Foam rolling epoxy on the surface may be a good route
I think I will use a vacuum setup at a minumum, possibly even resin infusion to make it as lightweight and achieve the strongest bond possible
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Thanks for tip @stoneburner , I’ll look into getting some behr acrylic sealer. I didn’t realize that could be applied overtop of the epoxy. No leaks in the board after the first test run so that’s a start.
@Cadenc very excited to read about how your board construction goes!
That looks amazing! Let us know how it holds up in use!
McDing had several threads about using Behr on epoxy. I’ve used it a couple of times now on epoxy.
Give the epoxy fill coat a light sand with 150 grit (possibly 220 would be good enough) before applying the Behr acrylic exterior concrete/tile sealer.
Interesting ideas here, I’ve been researching skin on frame kayaks. Seems some people are glassing over aircraft dacron, some over polyester materials, etc
In the late 60s, my father and I bought a Trailcraft canoe kit that fiberglassed over the canvas skin on a wood frame. My father was the one who exposed me to Guillow’s paper/tissue over balsa frame airplane models when I was a boy — Sopwith Camel and Fokker Triplane were the two I remember.
Since I’m planning to take a vacuum approach, there is concern about any of these in between materials being able to handle vacuum pressure without dimpling. I really think a hand layup is probably not optimal from a weight perspective and the fact that these boards will be much more sensitive to a solid bond between the glass and the filament.
Likely going to pre laminate a top and bottom sheet with a very thin layer of 2 oz innegra and then vacuum that upside down to both sides, before doing a final 6 oz layer bagged as well.
I have suspicion that wyve is doing hand layups in the videos and a seperate process in reality…I mean could be wrong but wouldn’t doubt it.
Seems like vac-bagging a hollow board would be very tricky…
NR,
Wanted a water-based urethane finish for a current project.
Found some “water-based” Behr “Spar Urethane” at HD (interior/exterior).
I’m thinking this may have potential for tissue sealing/tightening as well. Also might work well as an epoxy fill coat sealer.
(Who knows, might even bond paper to lattice better than water -based acrylic.)
I suspect epoxy will bond well with the “water-based” urethane.
Be sure to wear the same sanding respirator you would for sanding epoxy.
Much experimentation needed!
I’m curious what glassing schedule you are sticking with. I think my plan is 4/4 on the top and 4/4 on the bottom, one layer being e and the wrapped layers being s cloth
Another thing to consider is a layer/sheet of cork (1/16”, 2mm thick) between the 2 deck layers of FG.
Cork is impact absorbing,
“ Its cells have a unique 14 sided polyhedron structure that can be compressed to 15% of their normal volume and then regain most or all of its size and shape slowly. This compression capacity combined with a very slow rebound allows cork to act as a very effective energy dampener”
Lots to try! Definitely going to try some sort of sealer on the next board I do. I wanna go for a design like this for the next one: Burnsy Pro – Kanuk Board Co I’ve had really good luck with the LW-PLA foaming filament with 1 external wall and 0.6mm line width and 15% infill so I’ll probably stick with that next time instead of going for an open lattice structure.
For the layup so far I like 1 layer of 4oz over 1 layer of 6oz for my boards but they are smaller than most sea-going boards. I found two 4oz layers were too easy to puncture but ymmv. Up here in Canada I find my options pretty limited for surf manufacturing supplies so I’ve pretty much been using this Hexcel glass exclusively: Hexcel Fiberglass – Swell Composites
You should add a Coanda Channel to that Burnsy Pro. 
Got the frame assembled. Since there’s no stringer I used zip ties at the connection points for now just to add a little extra security until the bottom skin is applied. Seems to be working quite well.
Next up is laminating a 4oz sheet of fiberglass on a layup “table” (sheet of glass), letting that fully cure, and then vacuuming it upside down to the bottom of the deck
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Very cool! Excited to follow your progress!
Made a couple mistakes, but nothing too bad yet.
- I precut the fibeglass around the edge of the board before laying up on the wetout glass pane. The shape distorted after laminating so it wasn’t a sealed fit.
No big deal, just had to scrap that piece of 4oz. I decided to layup 4e and 4s together the same way, but without cutting the outline first. When it was in the green stage, I took it off the glass pane and used scissors to trim to fit around the board. Much cleaner and better all around.
- Last night I did a “dry run” with the vac bag. Thankfully so. Under vacuum pressue, even with the 4e x 4s fully cured with epoxy resin, the pressure is causing the bottom to dimple between the structure voids.
Solution: Place a thin piece of a flexible enough but still rigid material (in my case 1/8 hardboard wrapped in plastic) between the bag and the fiberglass skin. That should allow it bend to the rocker/bottom contour enough but will not be able to form into the voids. Basically want even pressure across the entire bottom, but only pressure directly pressing against the skeleton.
Planning to get some real bagging material and attach the bottom skin in the next few days.
Update:
Just pulled out of the bag, total failure. The epoxy did not bond well to the PETG at all. I sanded rough and even did flame treatment and it still pulled off easily
Documenting the failures is as important as documenting the successes.
Research…
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