Alternative DIY mast?


#1

I found these premade aluminum foil profiles. Does anyone have any experience with them or know if they’d work as a foil mast on a windsurfer(the FF13)I planned to cut them down to 95cm and reinforce them with a rod or pipe down the middle. Has anyone got any idea if this would work?
The Full foil 130mm

Website where I found them


#2

Would work yes, good find! If your looking forward a cheap option look up Clearwater foils


#3

I have done I wasnt sure if a wood and fibre glass mast would take the strain of a windsurfer


#4

More glass or maybe carbon would probably work


#5

The structure is all in the skins of a shape like this, adding a rod down the middle will not contribute anything significant to the strength unless it were structurally connected like the web as in an I beam.

Skinning it with composite would strengthen it (if needed, not sure it would be) but you would have to get a bond between the composite and the aluminum. Aluminum has terrible bonding characteristics unless treated, the oxide on aluminum (which occurs immediately on exposure to the atmosphere) will just peel off. Anodization is required, phosphoric acid etch anodizing is the best. Type III, PAA, ASTM D3933

Once the anodize surface has been bonded to the aluminum, the correct epoxy adhesive bonds nicely to the anodized layer.

There are kits available for small jobs http://www.sanchem.com/aluminum-pretreatment.html as an example. Automoble painting companies offered them as well.


#6

Taekni, I would have a possible concern about the strength of this aluminum extrusion for use as an efoil mast. The walls look a bit thin and also the alloy (6063-t5) is an easy to extrude, but lower strength aluminum alloy. It might be adequate but the hydrofoil masts I have seen have more “meat” on them.

For comparison:

7075 t651 yield strength of about 73,000 psi
6061 t6 yield strength of about 35,000
6063 t5 yield strength of about 14,000


#7

Thanks for letting me know Winging_it, the foil was being designed for a windsurfer but I suppose that means it needs to be even stronger, what would be the issue with the mast would it flex too much or would it just crack under the load and break off? If so could that be fixed by reinforcing the mast with an outer skin of fibre glass or a metal rod/pipe down the centre.
Do you also know what kind of force a a fuselage needs to be able to withstand?


#8

Taekni, if that particular mast is not strong enough, it will likely fail by bending permanently due to the low yield strength allow they are using.

Does anybody know what alloy the kitefoil masts are made from typcially? It would be good t know this for comparison to the Windknife extrusion.

If it turns out reinforcing is needed for the Windknife you might be better off using a proven kitefoil mast.


#9

I don’t see why this aluminum material would be any different from any other extruded aluminum used in the sport. In my commercial product design experience, although very stiff, the use of 7075 T6 alloy is very rare.


#10

According to this Zeeko website, most of the kitefoil manufacturers use 6061 alloy for the masts. 6061 T6 which has more than doulbe the yield strength of the 6063 T5 alloy used by the Windknife mast. Zeeko claim they are using an even better alloy now.


#11

Noted, yes, now I see the difference, assumed 6061.


#12

Another option is the manta foils discount masts they’re $55, they explain on the website why there cheap but it doesn’t seem like an issue and they come with inserts pre drilled and threaded.