Our 3d printed aluminum fd scanned 3 blades underperformed (produced little power) when skimming the surface (being half in the water half in the air, which is what you would do when motor is close to the board), contrary to the original fd blades. Despite the blades were sanded to being very smooth and the edges were made sharp.
It is depressing, because the only alternative is to buy the original.
Could be that producing it in cnc will solve the issue, but it is high cost experiment when not knowing the reason.
Interesting to see how your molded version would perform, but I am pessimistic.
Strange, my guess would be to limit max rpm in software to make sure it match the loaded rpm more closely and reduce the beahvior you describeā¦
These look amazing. Are you using the PETG-CF as is ? If so do they suffer from water ingress or are you water proofing them? And is it strong enough?
Are you sharing your designs? I would like to make a similar model (12s2p). I gave up on my last approach using aluminium 100x25 tube.
Thanks
Tim
@Bzhwindtalker The width is the same. I removed the antenna tray because I didnāt like the asymmetrical shape, and I wanted to keep the top of the unit cleanāso I didnāt want to put epoxy on top. Right now, Iām not using an external antenna, so I figured itās not really necessary. Or am I missing something?
If I were to add it, Iād probably design a tray similar to yours, but instead of mounting the antenna on top, Iād make a hole so the antenna could be fed through from the ESC openingāif that makes sense.
@thuffam Iām really liking the Bambu PETG-CFāusing it as-is, just making sure to dry it before printing. Iām using six walls, and I havenāt noticed any water ingress. If there is any, itās negligible.
As for the design, Iād actually recommend modifying @Bzhwindtalkerās original design to support a 12s2p layout. He uses a different ESC which is cheaper and his design is better.
My version is started from scratch mainly to learn Fusion 360. So mineās still kind of a mess. There are a lot of things Iād like to improve.
If I end up not liking the height of my current version, Iāll probably create a refined 12s2p version thatās hopefully worthy of sharingāhaha.
2 Likes
Send me pm, to get the onshape link 
Looks great. I will try the same - but out of interest, would it be worth me wrapping the cells in something like kitchen cling wrap before resiningā¦ so if I ever need to disassemble (and save weight of resin going between cells)?
For my next battery, Iām considering a design with a removable lid on the battery box and using silicone instead of epoxy. However, Iām not sure if this is a good idea.
Easiest way would be to use a tube style enclosure and then just seal one end where the connector is. You could then just paint the whole battery in plastidip before inserting it.
Iāve come to the conclusion though that building potted flight size packs is easiest and then if one fails its only 6 cells gone at a time instead of 24.
2 Likes
Yes, silicon would work. I use this one for work stuff, it is thermally conductive and has a good ratio of rigidity and ease of taking apart :
Silicone Bluesil RTV1523
2 Likes
I have checked out the model of @Bzhwindtalker and found that Gong users or anyone with M6 mast plate screws can reduce the screw holes width from 9 mm to 7 mm. You can gain 2 mm additional space in total for the 21700.
If I remember correctly Foil Drive also requires you to use M6 screws.
1 Like
I know its way after the fact and you probably know thisā¦ but for helping others looking at doing thisā¦casting with epoxy has several issues - a lot of exotherm if its more than 1cm thick (it will melt plastic). And unless it has fillers (eg a 403 powder or chopped strand) then it can crack under load. I believe special casting resins have fillers to prevent this. Iām not an expert - but have worked quite a bit with epoxy.
I have had success casting kiteboarding fins with inlaid fibreglass and using 403 (West System) powder. If you want to save weight, add some foam and/or use microspheres (which makes it much easier to sand but not at strong).
HTH
1 Like
Well there is a big difference between lamination/repair epoxy and inclusion/casting epoxy. That was my issue when doing the prop mold lately, used laminatikn resin to pour a small mold and it went thermal.
The exothermal risk with inclusion resin is almost zero, as I have poured 3kg into a battery pack with no overheating. The battery pack failed for other reasons but it was a soldi block.
I have more confidence in a full block of epoxy, with no air voids, than slilicon or box/lid/seal solutions.
Preparation for south west england trip and brittany. Went cheap with two more 35E salvage packs instead of p28, even from my bigger orders they come out at >4ā¬ per cell, and my focus and money is more towards the tow boat these days.
I had a good pa12 prop already on the old maytech, so preparing another pod ājust in caseā
Edit: wiring and cast done
3 Likes
Thanks - interesting Iāve not heard of the term āinclusion epoxyā - will have to get some to try it out.
Yeah totally agree with it being a better waterproofing solution than seals.
We may have a situation developping 
I have two complete pods and 3 batteries ready.
Hopefully no failure from remote, or controller box.
3 Likes
Nice! That would be closer to what people want to get into efoil/pumping. My version is on the extreme side of small battery pack for most.
Itās a thick boy tho, please try to weight it ?
Adam
Having a good time already with the assist as pump start solution that always work.
Had a unpleasant surprise when I noticed one of my newly cast batteries had some unprotected nickel strip on the top due to bubbles. I will have to buy some varnish, and other maintenance items for the trip general maintenance of the systems, like wd40 for bearings and silicon grease for contacts.
3 Likes
The weight is 4456 grams.
Pod, motor, battery, ctrl box?