The pre fab will conform just fine with a vacuum bag. You could also use something like a yoga mat and weights/a press but that would be super excessive. The weight is a valid concern, the fiber/resin ratio would definitely be rich
Epoxy should bond quite well to PLA, but PETG doesn’t bond very well with epoxy.
What about silk rather than tissue paper? Might work?
Edit:
Also quite curious if anyone is using snowboard topsheet material as the secret layer, such as nylon or something. It would bond well with resin.
So the filament I’m using now is a lightweight foaming PLA by eSun. The cost of this filament is $40 CAD ($30USD) per kg. The skim-style wakesurf board I just printed weighs 1.05 kg before glass. The previous surf-style board I printed weighed somewhere around 1.7 kg before glass.
Epoxy seems to bond quite well to the PLA plastic 3d printed filament. I’ve definitely played around with removing fiberglass from the printed boards and the epoxy bond can be stronger than the bond of the 3d printed plastic layers and cause them to pull apart before the epoxy gives up.
The issue that I had with epoxying the tissue to the board was that the epoxy doesn’t soak into the tissue and without the tissue wetting it won’t conform to the board and the tissue “floats” ontop of the epoxy. I’ll try it again though to see if I can figure it out. I suspect I would have a similar issue with polyspan and silkspan tissue if I tried to epoxy them down but I would have to test to know for sure.
Yeah seems like a transparent PETG plus 1 outer wall would work best for that, maybe a vacuum or infusion would help it get even pressure for a good bond to the filament.
I’m curious, what did you think about the board printed with the outer wall? I want to try one and I think that might be the method I’ll try.
I’m a bit worried about PLA just because of the melting point being a little lower than PETG, but maybe it’s a non issue?
In my experience if you just use regular PLA and do a board with 1 full outer wall the board WILL warp easily in the sun. I’ve lost a few boards (3 of 3) already to warping in the sun that were made this way.
If you use a “lattice” structure where the board surface is mostly voids the board will not warp easily in the sun even when printed in regular PLA… but then you have to figure out how to cover the voids nicely.
LWPLA seems to have a higher melting point than regular PLA and will fare far better with 1 full outer wall and will not warp easily in the sun. At the moment this is my favorite process. 1 outer wall and about 15% infill. I’m not sure how much sun LWPLA can take before warping though… I’m a bit scared to find out. lol.
So I’m obviously still learning lots about surfboard construction but one issue I seem to have is that when I have a sharp edge on a board its really hard (impossible maybe?) to get no bubbles near the edges of my fiberglass and then I have to grind those out and fill them. Here’s a pic that might be kinda hard to makeout:
The edge on this skim style board is sharper than 90 degrees and the lam was pretty tight when I left it but it popped up in lots of places while curing.
Is it recommended when shaping a blank to not have any really sharp edges and to make sure to put a “fillet” on each edge of minimum 1/8" or so? Then later if you want the edge to be sharper you could build it up with an epoxy dam? Or is there perhaps a special way to laminate laps on sharper edges?
With this board I used a 6oz (bottom) and 4oz (top) layer of cloth and I cut the 6oz to the exact shape of the board to make it easier for just the 4oz to go around the edge 1.5" to the other side but that still didn’t work. Thanks!
Generally as you describe the accepted way is to have a larger radius that will allow the cloth to wrap around and then build a dam when flood coating to build an edge. I have found when doing repairs that if you orient the cloth at 45* to the way you have, it sometimes that helps as well. Tricky when you’re doing a whole board though.
Purely Experimental:
In this case, I would try adding a thin coat of epoxy resin over the lattice surface and wait until tacky — I gauge tacky with a wooden match stick. Degree of tackiness needed is the unknown/experimental variable. (Place residual mixed epoxy on paper plate) my first gestalt would be to try bonding paper to lattice when gelled epoxy resin reaches stiff peek stage when poked with wood match stick, but still returns to flat on paper plate. But could need to be less tacky — determine by trial and error.
Then roll out the tissue over the tacky, resin-coated, lattice surface; smoothing flat/tight with a new squeegee as you go.
When the epoxy that is bonding the tissue/paper to the lattice becomes tack-free, coat paper/tissue with a thin layer of epoxy. Allow this new layer of epoxy to harden to tack free…
An idea for the 90* area that is bubbling- I too have experienced that with sharp corners. Lay out the cloth dry and spray adhesive the glass to the edge before laminating possibly?
Thanks @Cadenc that’s an interesting idea to try! I’ll have to do some more research on glassing skim boards and see how the pros do it… I think they use a press and vacuum. I wonder if a vacuum would work with these boards or if the exterior would get all dimply from the negative space in between the 3d printed infill.
The skim style board I was working on turned out awesome and rides great after filling the bubbles. Here’s some pics of the final product where I included a few bits of artwork my son drew and then we printed out on rice paper and laminated in:
@stoneburner I was able to rip all the fiberglass off the earlier lattice style board I made where I used tissue paper that was glued on with the floor sealer. Then, after removing the glass I cleaned it up roughly with some sandpaper and tried out this method.
I used a foam roller to apply epoxy to the board and then waited 10 minutes and then applied tissue paper on top and smoothed it out with my hands and this worked pretty well and i was able to get the tissue quite flat. I think the first time I tried this I was trying to get the tissue to wet-out and ended up giving up quickly but this time it worked out pretty well for the most part.
Once the epoxy dried I sprayed the paper lightly with a 50/50 water/acrylic floorsealer mix. I used enough spray to wet out the paper but not enough to cause drip marks. Then I let the paper dry for 30 minutes or so and it pulled itself into a nice taught layer made a little stronger with the floorsealer. Then I trimmed off all the excess paper and then fiberglassed both sides of the board with epoxy and 2 layers of cloth (4oz over 6oz).
This whole process seemed to work well but you need to make sure you get a clean seam with your tissue paper where the pieces meet or use a roll of paper otherwise it will mess up your glass a bit. I had a couple of issues I had to clean up afterwards.
Below are some pics of the finished project which could definitely use another coat of epoxy and more sanding but I got lazy and just decided to leave it after a fill coat and minimal sanding. I want to see if it starts taking on water again and if it delaminates before I put more effort in. I took it out for a spin this morning and the board rides just as well as the one it was modeled after. I’m also planning to put a vent plug in it at the rear shortly.
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.
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
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!
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.
