DIY Hydrofoil Mast v3

Building a Carbon DIY Hydrofoil Mast v3

[@Helic4]

Can't wait to see you test it with the last hydrofoil !!

[@fluiditynz]

I'm too heavy, that wouldn't be strong enough for me. I've been working about 5 weeks on mine. First the design, then 3D printing the top and side shells, sanding them, applying shellac, more sanding and then polishing them with mould release wax. Late last week I cut the carbon fibre cloth, 30 layers of 300gsm/sqm sandwiching a skinny infusion bleeder core I 3D printed with reinforcing struts. Friday morning I finished the fibre layup and sandwiched the sides. Saturday I cut double bias and unidirectional patches to spread the spayed sides and fill the top plate cavity fully. Friday evening I fit and taped sections of chux cloths between all the edge faces and tightened the alignment bolts and threaded rods that run fulll length and through the top mould cover that has drilling and cutting indent guides for the board screw attachment bolts. I fitted the infusion hose through a hole in the top plate and into the infusion tube top funnel section. Today I had a late sunday start after lunch. Taped all the vacuum bleed lines, resin brakes and resin infusion lines and the mould into a large vacuum bag. Looked on thingyverse for a good rotary stirrer, printed one but didn't like it much, designed and printed my own. Cleared the CNC table partially, set out the bag with mould in the garage, pulled a vacuum and checked no leaks. Took out my non return valve which wasn't working properly, rechecked my mast volume at 1.95 litres, mixed up 1.8 litres of river table epoxy and waited a bit for bubbles to rise, started the infusion. Part way through something gave way on the vacuum bag and lost vacuum. Hunted for the hole but couldn't find it. Over bagged it and carried on. An hour and 20 or so from start, all the edge chux cloths were looking wet. 10 minutes later, most of the resin was used up. Finally noticed through the transparent side faces of the 3D printed PETg+ that many of the infill cells of the mould had absorbed around 25% full resin. Explained the large resin consumption, relaxed. So now I wait until Wednesday for de-moulding. I covered the sides with polystyrene foam, over all with 2 layers of cloth and I expect I will be able to turn off the vacuum pump tuesday evening. I did a smaller scale glass fiber infusion test first to try the technique and it worked great. I'm expecting it to be around 3.3kg demoulded. I'm hovering around 115kg so it has to be strong.

[@fluiditynz]

Update to my own mast, had several sessions on it now and loving it. Resin infused through 30 layers of Carbon split at the top for the flange.

[@HANDIY]

@@fluiditynz Nice Job!

[@skiboy1970]

Awesome thanks for the video.

[@jimmym2719]

Wow 🤩 that’s cool. I want to make one. I just share my previous experience doing RC glider body. I will try using foam board shaped to profile in place of the expended foam later just dissolve away using thinner to hollow out. Thanks for sharing your building video. 💕

[@HANDIY]

its a good Idea, if you do that you might be able to overlap the leading edge carbon over that foam core, something i couldn't do with expanding foam.

[@jimmym2719]

@@HANDIYwo yeah..I didn’t think of that. That will make it stronger at the leading edge..thanks bro..that’s a better idea for strength. Awesome.👍

[@billydasher5518]

You've given me inspiration to make a carbon mast, great idea using foam to pressurise the mold. Is the v3 noticeably stiffer than v1?

[@HANDIY]

Good luck with your mast. Let me know if you figure out how to improve the method! V3 is indeed stiffer especially in the twist/torsion of the mast.

[@bertrandcordiez6367]

Hello, How many layers of diagonal and unidirectional 11oz did you used? I heard that some mast use 50 layers of fibers…

[@claudiobertadeazevedo4669]

IMHO there is little difference on drag above 600 grit sandpaper due to the fact that water will stick to the 600 "grooves" and create a polish like laminar flow when inside the water, HOWEVER salt will stick more when dry to 600 grooves then smaller or polished surface

[@asved86]

Thank you for the inspiration for my first mast build. Do you think the same method could be used for the hydrofoil wings? I am planning to 3D prints the moulds for mast, front and rear wing. Then basically use the same method as you with the foam. For the wings the foam will then remain. Do you have any recommendations?

[@HANDIY]

it would be a bit more complex for a wing especially to get the seams strong enough and also the bolt holes area would need some extra reinforcements. But you're approach is close to what manufacturers are doing so i'm sure it can be figured out. Good Luck!

[@asved86]

Sounds good! I have been recommended to use epoxy foam to skip the step of removing all foam filling with epoxy. It will be for an efoil so I also need to secure tubes inside the mast for motor phases as well as for cooling. The threaded inserts I think I will secure afterwards. How much carbon do you recommend to start with?

[@pianex9045]

i love you channel

[@HANDIY]

thanks for the nice comment 🙂

[@pianex9045]

@@HANDIY no problem

[@user-li4wv9kk8u]

How much carbon tape did this use?

[@florian367]

Hello, and thanks for sharing ! I am also making a mast. I'm planning to make a core XPS with NACA16012 profile chord 14cm, and then strat around ~3mm of biax and 90deg carbon layers in one go under vacuum. I have also the possibility to copy a mast with 2 molds, but the problem is the bonding of the 2 halves. How is your bonding on this mast ? Thank you

[@HANDIY]

The v3 mast is solid with no issues so far, the extraction of the PU replaced with high density filler/epoxy is what makes such a good bond between the 2 sides in this mast. If you're going to shape a core then laminate it, make sure the core is extra slim, you can always add more layers of carbon until you get the right thickness. A mold is probably easier to guarantee the right thickness and shape right away. Best of luck!

[@EvanFoiling]

What is the total material cost? The goal of carbon is to be as stiff as possible. Can you do stiffness tests? You can do them by bolting the foil to the ground and hanging weights and measuring the deflection. Also applying a torque to the end and measuring torsional flex. I am curious how these compare to the pro model you made the mold with and compared to my pro aluminum mast.

[@HANDIY]

cost of material for this mast was around 100$, I'll try and do a proper stiffness/torsion test in the future, but when quickly comparing the 2 it feels like this mast is about 10% less stiff, and also 10% less stiff in torsion then the factory made carbon mast i used for the mold. This is just an estimate and obviously i could add more carbon into the mold in the future, but im not sure if i'll ever make another mast since this one is rock solid and i dont feel like i need a stiffer one at the moment.

[@bertrandcordiez6367]

Hello, when you pour the expandable resin, how do you make sure that it does not slip into the joint of the carbon lamination. If this is the case, there is a risk of poor gluing, for example at the trailing edge in the video (0:43).

[@HANDIY]

Good question, I was initially worried about this as well. if you look at 1:14 in the video you can see that the leading and trailing edge have a decent thickness of epoxy/carbon gluing the two sides together. When closing the mold the carbon/epoxy on each sides get press together at the seams, creating an airtight seal at the seams. The pressured foam want to push everything externally, so as long as the mold is shut tight with 0 possible give, the seams should be airtight, the carbon and epoxy at the seams will be pressed against the seam, the excess pressure should come out the top and bottom. To be on the safe side i fill the entire cavity with and epoxy mix that way i'm sure they will never split apart. Also my mold has one side fitting into the other instead of perfect halves pushed together, which probably helps making the seams airtight.

[@jordanavery1735]

Any thoughts on creating a front wing following a similar method displayed here? I have seen your videos where you created a complete hydrofoil, but I am interested in a method that does not use a wood core like how you do the mast here. I recently "deconstructed" a front wing from a big company and it appears they use some sort of foam core with fiberglass in the center where the screws pass through, and I'm trying to figure out how to replicate this to duplicate a front wing I currently have from this company that may nearing the end of its life.

[@HANDIY]

You could probably do something similar with PU in a wing mold, but i havn't tried yet. Bolt holes reinforcements and the seams would be the tricky thing to figure out.

[@ab-ii8pt]

Hello, I have a question, why do you alternate layers of carbon and glass instead of pure carbon for the mast base?😊

[@HANDIY]

My base plate needs to be at least 6mm to accommodate the countersunk M8 bolt heads, I used fiberglass mainly for extra thickness and to save carbon.

[@mavisevda]

Did the two pieces stick together? Did you sand before pouring epoxy in?

[@HANDIY]

the mast leading and trailing edge do stick together in the molding process. I then extracted the PU foam and sanded the inner wall of the mast to remove any PU left, the poured epoxy completely glues the two sides together and adds a lot of compressive strength, the mast still weights less then an aluminum factory mast.

[@printrun5]

@@HANDIY ok this answered my question about the filling. Now I know how to take this even further and make it even lighter, yet stronger!. thanks a lot!

[@charles-andrelefebvre1154]

@@HANDIY but filling it with epoxy is much more weight than filling the mast with a mix (fiberglass + epoxy)? I am new to composite, please correct me!

[@printrun5]

If I understood this well, you just filled the entire mast with the resin, after you removed the foam. Is that correct? I wanna do my own Hydrofoil setup, and this is very inspiring.

[@HANDIY]

correct, except i filled it with a mix of high density filler and epoxy, you'll be surprised by how little you need it fills quick. good luck with your setup!

[@printrun5]

@@HANDIY thanks for super quick reply! may I ask what means “high density filler”? what is it good for?

[@HANDIY]

@@printrun5 I use "west system 404 High-Density Filler", its a powder that is mixed with the epoxy to thicken it, it saves a bit of epoxy and maybe weight without loosing compressive strength. But you can use pure epoxy to fill it and it would probably work just as well. Its not really necessary to fill the entire mast with epoxy/filler, but it makes the mast super heavy duty.

[@Foodmagnet98]

Hello, subscriber here. Is there a link to where you buy the 3" 11oz carbon tape, is it avail in the US?

[@HANDIY]

I but it from www.uscomposites.com/

[@ceritamenarik1111]

What is the name of yellow liquid in the middle of the mast sir ?I think that is not too hard and easy to remove

[@HANDIY]

Its Polyurethane expandable foam 3ld density

[@mauromariani4120]

Hello, do you have a plan with the mast section? thank you!!

[@HANDIY]

if you have a look at the V1 Mast Build video, you can see how the mast mold was made. Cheers!

[@mauromariani4120]

Hello, I finally built a neck with a Paulownia wood core covered in carbon fiber and epoxy resin. Thank you very much and congratulations again for your work. This next weekend I'm going to try it!@@HANDIY

[@alvarotovarprieto1630]

Do you know the final weight of your mast? Thanks

[@HANDIY]

This mast weights 1.7 kg, it is 90cm long

[@ceritamenarik1111]

How thick is the mast sir ? How wide is the mast sir ? cm please...

[@HANDIY]

93 cm long, 15mm thick, 12cm wide

[@pianex9045]

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