I think that the resin will slowly rise inside the hollow spaces, because (with FFD 3D printing) there are usually small air leaks. So the resin level will continue to fall slowly in the space surrounding the box. And it will be difficult to not get resin into the fin-tab slot. Of course, you could tape it shut, but how do you then ensure the correct cant angle, without a fin dummy in the box?
You are welcome RDM.
I think the ease of routing an oval cavity for the nstall and wider Futures slot will be great enhancements for V4.
My opinions are make it so you print bottom to top. Add a lip or flange around slot like futures that will be sanded flush with hotcoat…so that there is a known amount to sand off and height to install plugs(flush with foam or lam). And they should fit as tight as possible into the routed slot for the strongest install. Thats the key to fusion and futures strengths. All the asian boards with future fins crack around the plugs because they are sloppy with there box route and there is a perimitere of resin around the plug that is week even when glassed over. The way the box is designed now it would print fine from bottom to top on any printer…no need for supports.
Thanks MrMik for informing me that your type of 3D printer may not produce an air tight model. Also, would you always print from bottom to top as deez has suggested?
The latest model shown above would print fine from botton to top.
I developed another technique during my fin printing adventures, I call them ‘Soaker Chimneys’.
The method could be adapted for fin boxes, to that there will be an entry point for a 10ml syringe filled with resin (or some other suitable glue), then pressure fill an extremely thin space between printed part and routed foam, through a network of 3D-printed channels.
Your “soaker chimneys” sound very interesting MrMik. I think I get the gist of how they would operate.
But for now I’m going to stick with the basic design I have with one main adjustment that I have in mind - a small outward return flange around the bottom edge of the outer box wall whose periphery will be a perfect match/tight fit for the routed cavity in the board. This will help to give and control a uniform spacing all around between the box top periphery and the routed cavity as well as help prevent resin leaking around the bottom edge and up into the hollow spaces. This would allow you to simply rout the cavity to the correct depth (+/-0.5 mm) push the “tight fit” box in and then pour the resin in around the edge of the box. I’m thinking of a gap all around the top of 2 mm. Would this be too tight to allow the resin to flow down properly in not too long a time?
RDM- like this? Picture also has Deez’s suggestion to make the top more ‘finboxy’ with a localized ridge around the slot…
Exactly that J - perfect! I was intending maybe to add localised rib around the top outer edge as well as the slot. I could shape the profile of the outer one to help direct resin down into the gap - to give you a bit more leeway as you pour the resin.
I think that either the ‘outward return flange’ will not seal tight enough, or it will make insertion of the box into the routed out foam difficult. Maybe both. It depends on how thin the resin is.
How about a sharp edge that is prutruding underneath, to be pushed into the foam? That would again necessitate printing upside-down, though. And may not work for center fins because the harder stringer would stop the edge from being pushed in.
don’t you think you need to create some small slots on the top part to let air bubbles go out of the plugs during installation? I’m telling you because in the past I designed a fcs2 clone and you can find it here on swaylock, the first version was without top holes and during first installation i realized my mistake, I added even holes on the sidewall (without support) to have better anchor on the foam and it was evel faster to print them.
I had another account on swaylocks that now is blocked probably due to inactivity anyway put in the search FCS2 clone and you’ll find a thread from nemoz_z.
I feel like the best option would be this overall design with all of the bracing in place but simple close the bottom off completely. That way you could make a router jig to get a tight fit…no resin extra resin going into the plug. And one could choose their own infill percentange for the extra hollow space. . You can even make certain parts more sturdy by using an infill mesh in your slicer. The strongest install will be the one that fits tight in the slot with minimal resin around the perimeter.
Link to the FCS2 printable thread: https://www.swaylocks.com/forums/fcs2-compatible-3d-printable-plugs
One of the conclusions from that thread was that people may need to adapt a design to their intent versus one type to fit all.
I think the main thing would be for the modded versions to reference the source file like V3_flanged or V4_smooth or V4_slotted so there is a family tree of sorts.
For example, for me with EPS, resin drainage and resin exotherm are concerns. So the extra 2mm flanges and annular ring filled with resin seem like a liability.
So I would take those off of mine and rout everthing close to nominal so that there is a tighish fit. I would paint resin onto each surface and then assemble.
If I were doing PU or a hollow wooden board (HWB) the 2mm (5/64") per side gap might seem a hair big, I’d probably go 1 to 1.5mm (strong 1/32" to just under 1/16") per side.
Being conservative with the resin and then doing the touch-ups with a syringe sounds neater than filling the cavity too much and having to mop up the excess.
I am enjoying the discussions, thanks for everyone’s input.
Thanks to everyone for their input. I have learnt a lot about people’s preferred fitment methodologies and printing capabilities.
I know I’m not going to be able to please everyone, so I’m going to have to choose what I think to be the best “average”.
I will make a simple box shape and (almost) enclose those outer volumes completely - will need to have a hole in each separate volume on its bottom face to allow unfused particulate matter (SLS printing process requirement) to be removed. Hopefully these small holes will limit resin intrusion into these volumes if the boxes printed on domestic 3D printers aren’t airtight enough to trap air in these volumes. SLS printed boxes will not have any resin intrusion issues into these volumes. Resin should be able to be poured into the routed cavity and then the fin box pushed in and/or poured in after the fin box is dropped in.
I will add a rib (to be sanded off after fitment) around the outer edge of the top surface to help prevent resin flowing onto this surface and into the fins slot and screw holes. This rib will be slightly offset (inboard) from the outer edge in order to allow the box fitment depth to be checked against the surrounding board surface before fitment.
Now to find the time to get it done.
Rohan, You’re a good man to do all this work for free so other Swaylockers can try something new. I’m sure it’s most appreciated by all.
Thanks for all the effort you put in! Unfortunately I’m still too busy to contribute much at the moment, I’m not even designing or making fins.
Regarding the hole in the bottom, that is an easy fix in OpenScad to close the hole if desired
In the end I decided to place the top surface rib around the fin slot instead. I figured if I put it around the edge of the top surface it would be difficult to get resin out of the area if it happened to spill over. So tape will need to be applied over the screw holes in case of resin overflow and the fin box edge should be mounted 0.5-1.0mm overflush to the surrounding board surface and then everything sanded back flush afterwards.
Thanks Brett. But really I’m only giving back what I should in return for the knowledge and great advice I’ve received from Swaylocks and the generous people here.
Looks good!
One could also print the top entry to the screw holes closed, if 0.5mm gets sanded off that means at least 2 layers, which will prevent resin from entering in a little spill.
Thanks MrMik. On the original side box design many moons ago I had the screw holes covered to do just that but was asked to remove the covers as it was expressed that some people use a fitted fin to set alignment/angle when setting the box. I was told it was no trouble to cover them with pieces of tape to prevent resin entry.
I like to use a fin fitted in the box to get the angles right and using tape does away with more sanding.
I think this idea could be a boon for spongers, there’s a lot of smaller, trailer type fins that would improve the hold and drive of boogie boards. There’s a few bespoke fin companies but no thriving fin market for spongers so this would be a product to sell with no competition.