Glassing 3D Printed Boards

I’ve been 3D Printing some smaller surfboards for wakesurfing and then fiberglassing overtop using Epoxy resin and its going pretty well so far. I’ve done 4 so far… pics at the bottom for anyone interested! Normally the process (post-shaping) is pretty similar to a foam board and the printed blanks I’m using have just a thin exterior 3D printed wall. Recently, however, I’ve been trying to create a “latticework??” style board like the ones done by Wyve and Paradoxal 3d printed surfboards but I’m unsure the best way to glass overtop of the voids.

I tried the technique used by cardboard surfboard makers (which has similar open voids) where you lay the dry fiberglass overtop of the board and then slowly wet it out with a brush dipping it frequently in resin but that seemed to result in some waviness where the fiberglass would bow under its own weight in between the lattice and it was hard to avoid drip marks in the middle.

Next, I tried laying out 1 sheet of 4oz glass on a flat sheet of plastic and wetting it out there and then transferring it onto a board when wet. This seemed to work initially but it had a serious issue where 1 sheet of fiberglass wasn’t thick enough to hold onto the resin and it dripped through the cloth. Once dry, I then added two layers of 4oz glass overtop and the board looks ok but you can see the drippings on the original layer and there are also still bowed areas between the latticework.

Next I tried laying out 3 sheets of 4oz fiberglass on a flat sheet of plastic, wetting it out there, and then transferring it to a test piece of a board. This worked better and held onto the epoxy well but it still has issues with some bowing in the voids. This method also doesn’t seem to want to stick as well to the blank since the layers of glass are now somewhat stuck together and less malleable. After fill coating the test piece looks ok but its still not perfect.

I’m wondering if anyone has any ideas on the best way to glass over a latticework style board and achieve a smooth consistent finish. I assume there must be a way if Wyve and Paradoxal are able to do it but I haven’t been able to find any videos on their glassing process online. Thanks in advance for any help!

I tried adding pics but it wouldn’t let me so here a link to a google photos album:

I intended to try this when I wanted to make a hollow board.
My father and I, many solar cycles ago, made Guillow balsa frame/tissue skin, flying airplane models.
You bonded the (paper) tissue to the balsa frame with clear airplane dope by painting the frame exterior surfaces with that dope and applying the paper. Shrank the paper tight to the frame by wetting with water, then painted the dry paper skin with colored (or clear) airplane dope.
Seems like the same could be done with hollow surfboards. Bond the same type of paper to a lattice board frame with something like Minwax water based Polycrylic finish. Wet paper with water, then let paper dry/shrink and seal with the same Minwax Polycrylic.
Once sealed add a coat of epoxy resin let it set to tack free and then laminate the first layer of FG cloth. Then glass as usual.
Huck built a hollow frame board with what I believe were thin polyester cloth skins — similar to the process I described above.

Thank you so much for the awesome suggestion and for the link to Huck’s older thread that is so chocked full of great information. I had no idea that thread existed. Looks like I have some research to do on the different fabrics/tissues/coatings that can be used under the fiberglass to provide structure while the epoxy sets.

If you watch this video on the wyve boards you can see right at 34 seconds where they pull some glass over the board and it looks like the board is already coated in tissue or a light fabric of some sort… hopefully this is the solution I need!

Make some lattice test panels and experiment.

What kind of material is your lattice made of?

I suggest upside down + bleeder cloth

It’s made of PLA plastic

Hmm this is definitely an interesting idea as well… or maybe wrapped in plastic and upside down could work too. Something to try with some test pieces for sure. Thanks for the help!

So, I’m going through a process of testing different methods to accomplish this but in the interest of saving some time I just asked Wyve by email how they do it and they were nice enough to send me a reply. They said that sometimes they use fiberglass with nothing else and sometimes there’s a micro-sandwich foam inside… but I think that means regardless there is nothing underneath the fiberglass. They did stress that the biggest thing is “you have to let the resin cure before sticking it to your 3d printed structure!” So I take that to mean that I need to layup my fabric (prolly two layers of 4 oz?) and some resin off the board and then wait a while for it to start to harden and then apply it to the board once it can hold its own shape… Then I think I’ll sand the rough edges once dry and add one more layer of 4oz ontop. Gonna go try this right now and I’ll update in a day or two with some results.

Test 1 - Tissue paper

Method: glue tissue paper around sides of piece with white glue, allow 1 hr to dry. Spray twice with watered down urethane to tighten paper and add to rigidity of the film. Place 2 layers of dry 4oz cloth ontop the piece and wet out as per normal.

Results: Seems to work very well. Tissue paper is hard to not get any wrinkles or tears in it. A few small wrinkles or tears does not affect the flatness of the fiberglass but you can see the mistakes through the glass. Epoxy appears to have soaked through the tissue and is bonded to the piece although the bond is a bit weaker than I would like. Finish is nice and flat and there are no drip marks. In the middle of the voids you can see that a bit more epoxy has gathered (glossy look) but as the finish is very flat I think the tissue may have continued to tighten as the epoxy dried.

Test 2 - Plastic wrap, upside down

Method: Lay up two layers of 4oz on a plastic sheet and transfer to test piece. Wrap with plastic wrap and tape tight on backside. Let cure upside down.

Results: Does not work well or result in flat finish. Epoxy pools flat on plastic wrap at the bottom and fabric floats up. Bleeder fabric would be needed to make this method work which I’ll need to grab at some point although I don’t have great hopes.

Test 3&4 - Letting epoxy cure before applying

Method: Lay up two layers of 4oz on a plastic sheet and let cure before applying. Test 3 was allowed to cure for 1 hr. Test 4 was allowed to cure for 2.5 hrs. Using Entropy CLR resin with fast hardener (4hr dry). After applying Test 3 I realized I needed to add a fresh coat of resin to the test piece before applying the layup which I did for test 4 and it adhered better to the test piece.

Results: No drips and a clear finish were achieved but neither test resulted in a flat surface despite my attempts to pull the layup flat when applying to the test piece. Needs more testing with longer cures, thicker fabric, and possibly a “micro sandwich fabric”.

New test:
I would apply a thin coat of epoxy to your pre-treated/tightened paper and allow it to cure enough (less than 24 hr) to cause the paper to tighten up before laminating a single layer of cloth.
You may need heavier paper tissue than you are using.

Yeah I don’t think the paper I have would take epoxy without ripping so I’ll need to get thicker stuff as you suggest to try this method. I originally tested strengthening/tightening the paper by painting on urethane but even that was too thick which is why I opted to spray a thinned down version for this test.

As a sidenote: my first few test boards were all done using a single 3d printed plastic exterior wall to save weight which seemed to work great at first glance and is what I’ve seen a few other people do online. However, what I’ve found is that when the board is left in the sun on a really sunny day the exterior wall warps because it is so thin and you get a bubbling effect in between the infill layers which looks like this…

If I print a board with thicker walls (ie 1.2mm) then it takes a lot more heat to warp the exterior wall of the board and I think it’ll probably be ok in the sun. Also, if I print a board with a latticework pattern like this then the board also seems to do better in the heat although I’ve only tested to around 55-60C by pointing a space heater at it and measuring the temperature of the exterior of the board.

It’s an interesting construction method. Makes me wonder what it would take to use the same process for the cardboard surfboard approach, only to remove the cardboard out at a late stage…

Test 5 - Tissue paper, epoxy coat, glass

Method: Apply tissue paper to test piece with white glue around edges, allow 1 hr to dry. Coat with thin epoxy layer. Leave to set for ~16hrs. Place 1 layer of 4oz cloth ontop and wet out in place.

Results: Very flat result, no drip marks. Epoxy has soaked into tissue and turned it more transparent than in previous tests. Fiberglass and paper have bonded well but I’m unsure how well the paper is bonded to the plastic. Need to test what kind of weight 1 layer of fiberglass can take over the voids.

Test 5,6,7 - Testing thicker cloth

5 - two layers 6oz cloth layup on table - no cure time before transfer
6 - two layers 6oz cloth layup on table - 1hr cure time before transfer
1 - 1 layer 6oz, 1 layer 4oz cloth layup on table - no cure time before transfer

Results: Two layers of 6oz cloth results in much less sag than 4oz. 1 layer of 6oz and 1 layer of 4 oz is better than all 4oz but not as good as all 6oz. Letting the epoxy cure 1hr before transfer doesn’t seem to affect the sag of the cloth but it does seem to reduce drip marks quite a bit so I think its necessary without tissue underneath.

I think the next thing I really need to do is figure out what I want for weight bearing across the voids while also keeping final board weight in mind. The original complete test board I made had three layers of 4oz glass and a hot coat and it seems pretty solid but the weight is getting up there. Lots of epoxy pooled into the recesses during the hot coat and made it quite thick so its not a great example. The final board I make will also get a foam grip padding on the top which should help with weight distribution.

The tissue paper method works the best so far for producing a flat finish that is free of drip marks but its a bit more work and adds some color. It would be nice if I could find it in longer sheets so I could cover the board in one go. I might need to get a roll. I’m a little unsure of the longer term effects of using tissue paper on a board. I’m worried it might it delaminate from the plastic easier so I probably need to find a better way of gluing it down than white glue. Epoxy might be best but please let me know if you have any suggestions. I wonder what would happen if I put the tissue in between the layers of fiberglass when doing a layup off-board… something to test!

In the 70s a mate tried something similar with lateral foam strips as the lattice, with about 2 inch voids. I think small fractures led it to leak as after a session the board was half full of water, lol. Maybe just something to consider?

What if you try the rice-paper that people traditionally use for putting printed graphics under their layup? It would clear up on lamination, and bonding is not an issue as far as I know, at least not when it is between foam and cloth.

no expert, never done anything like this but the thought just popped up