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Sealing alu strut - still a no-no?

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Re: Sealing alu strut - still a no-no?

Postby cglazier » Thu Mar 15, 2018 2:31 am

The North hydrofoil comes with a sealed aluminum mast.

CG

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Re: Sealing alu strut - still a no-no?

Postby Peter_Frank » Thu Mar 15, 2018 12:34 pm

opie wrote:
Wed Mar 14, 2018 9:12 pm
My Takuma mast came sealed from the factory but now it has water in it that I can't get out. Maybe a fluke or maybe its not that easy to seal.

This is exactly why I would love the idea I mentioned, having the mast sealed, but having a "vent plug" of some kind (like we know from windsurf boards maybe) so you can drain, as even if sealed, water sometimes WILL get in.

8) Peter

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Re: Sealing alu strut - still a no-no?

Postby Dwight » Sat Mar 17, 2018 2:32 am

Look to windsurf booms for the answer. They’ve been filling them with foam for longer than some of you have been alive. 😝

They don’t try to seal the boom bodies tight, they just fill the cavity with extruded polystyrene. It is the spongey white foam that is water proof. Many foils come packed in expanded polystyrene. I sliced up that packing and fill the mast cavity.

End result, 80% of the void gone. No worries. Minimal water capacity.

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Re: Sealing alu strut - still a no-no?

Postby jaros » Sat Mar 17, 2018 11:33 am

Look to windsurf booms for the answer. They’ve been filling them with foam for longer than some of you have been alive.
They don’t try to seal the boom bodies tight, they just fill the cavity with extruded polystyrene. It is the spongey white foam that is water proof. Many foils come packed in expanded polystyrene. I sliced up that packing and fill the mast cavity.
End result, 80% of the void gone. No worries. Minimal water capacity.
I think all of the ALU foil producers should use this method mentioned above. I did the same with strips out of XPS. It keeps 99% of the water out, it adds almost zero weight and you can always get them out, rinse the inside of the strut with fresh water and put them back in.
I really can not see why they are not doing it...
Greetings,
Jaros

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Re: Sealing alu strut - still a no-no?

Postby merl » Tue Mar 20, 2018 1:32 pm

jaros wrote:
Sat Mar 17, 2018 11:33 am
I did the same with strips out of XPS. It keeps 99% of the water out, it adds almost zero weight and you can always get them out, rinse the inside of the strut with fresh water and put them back in.
I really can not see why they are not doing it...
Greetings,
Jaros
:thumb:
I'd be interested to see some pics/vid of this mod if you have a chance!

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Re: Sealing alu strut - still a no-no?

Postby BWD » Tue Mar 20, 2018 4:06 pm

Actually the white spongy stuff used in packing, boogie boards and windsurf boom plugs etc., that has slippery feel and doesn't crumble, is Expanded Polyethylene (PE).
At least, that is what has been in my old windsurf gear.
Extruded Polystyrene (XPS) is the more rigid stuff, used for insulation board. It shapes ok but melts in polyester resin and epoxy doesn't always stick to it as well as other foams.
it also doesn't absorb water, is more rigid than other light core foams, and tends to break down if in contact with water for too long, especially in heating or freezing cycles. just fyi

The soft Polyethylene (PE) foam for plugs is a pretty good idea, but if you are anxious about it, maybe also a good idea to weigh your mast dry and reweigh it periodically.
If it gains weight, there is probably water in it, and you should take the plugs out!
merl wrote:
Tue Mar 20, 2018 1:32 pm
jaros wrote:
Sat Mar 17, 2018 11:33 am
I did the same with strips out of XPS. It keeps 99% of the water out, it adds almost zero weight and you can always get them out, rinse the inside of the strut with fresh water and put them back in.
I really can not see why they are not doing it...
Greetings,
Jaros
:thumb:
I'd be interested to see some pics/vid of this mod if you have a chance!
This is also an interesting idea. Aside from labor/cost, one reason not do it is that one of the bad scenarios for corrosion is to have a small void or channel next to your alloy and fill it with salt water, and maybe some other contaminants. Eventually some customers would end up with metal filings, bits of sand, salt water etc pooling in there, wearing away any paint or anodizing inside, and causing unseen corrosion.

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Re: Sealing alu strut - still a no-no?

Postby knyfe » Fri Aug 30, 2019 8:53 pm

I have the same leaking problem with my Liquid Force Alu mast. Should I just foam it out with the construction foam? I tried many different fillers as end caps but they all leak after some time. I dont want to disassemble the foil each ride just to get the water out. Thats just stupid ... Any other suggestions?

G

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Re: Sealing alu strut - still a no-no?

Postby tegirinenashi » Sat Aug 31, 2019 3:05 am

Use thin jewelry screwdriver or knife with sharp tip to take the plugs out. Be careful: if you don't catch the plug with the tip of the knife, it will drown down inside the mast under the pressure when you push it. Instead, poke the plug at 45 degree angle to depth of couple mm and pull it.

Cover the plug walls with some glue, such as rubber cement, and insert them back into the mast voids. Optional: fill the void with Styrofoam or some other filler before sealing the mast.

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Re: Sealing alu strut - still a no-no?

Postby Foil » Sat Aug 31, 2019 7:31 am

Kamikuza wrote:
Tue Mar 13, 2018 12:35 am
edt wrote:
Mon Mar 12, 2018 9:38 pm
ok. Well the slingshot mast is sealed how did they do it?
I think it's a "rubber" bung that goes all the way through. Seems to be standard

it is a rubber bung in each of the gaps, but its only around 1cm thick and can be removed easily by knocking them out from the other side, quite dense hard rubber, ideal if you are cutting down a mast as then you can reuse the bungs like I have done.

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Re: Sealing alu strut - still a no-no?

Postby RichR2 » Sat Aug 31, 2019 7:59 am

I've used silicon sealant on a couple of masts and never had any water getting in. Just make sure you thoroughly clean the inside surfaces of the mast where you inject the sealant. If you need to remove it it's very easy to do with a sharp knife.


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