I just finished doing my first DIY repair on my Fanatic Stingray windfoil board. As part of the clean up I hosed the board down with water but then realised I'd forgotten to put the vent plug back in. I'm not sure how much water got in there, it was a pretty quick wash mostly focusing on the nose of the board. I did a quick search of the forum and based on that turned the board upside down for a couple of hours, and then right sided it and put in a paper towel wick. The paper towel wick got wet so water definitely got in there.

Question for the forum is what exactly is going on down there? What happens to water when it gets down there and how bad is this? Based on what I could see of the inside sandwich when I did the repair the construction looked a bit like compressed cardboard. Has the water just been soaked up by the sandwich? How bad is this?

I live in Melbourne so about 22 degrees max at this time of year so steaming the water out isn't really going to happen. Beyond inserting a paper towel wick are there any other approaches worth trying (hair dryer, dump some rice in there, keep it in the house instead of the garage, ...?).

So the inside core is a low density polystyrene. made up of bean bag cells compressed together, each cell is fairly sealed, but there are gaps between the cells. So there's no a lot of absorption, but there is free passage, the water goes with gravity and airflow.
My normal way to get water out is with opening at lowest point and a wick making good connection to the foam.
To aid this, heating the board will cause an airflow out of the hole. easiest way here is with a black plastic cover over the board and left in the sun until the wick stays dry. Depending on amount of water this can take several days, but in your case, as long as you have had the bung left uppermost too long, it could happen reasonably quick.

The water won't affect the material inside the board, but there is a risk of delamination if you forget to undo the bung in the heat. As well as the normal expansion of air you get extra vapour pressure from the water. This will find any weakness in the bonding of the laminate and cause a surface bubble to appear. This can then quickly spread over most of the surface.

No problem, just leave in sun with paper towel.
Not much water got in. Happened to me sailing away without the plug.

Leaving your board in the sun is never a good idea. You have no control over how hot it will get. The black plastic idea in the sun is even worse. Definitely don't use a hair drier !!!
It doesn't sound like much water has got in.
leave it with the vent plug facing down in a warm dry space out of the direct sun.

Most epoxy is heat cured to 55deg to get max hardness. True if this hasn't been done getting anywhere near these temps will complete the cure and lead to some resin shrinkage. leaving the cloth texture showing. But he's in 22C It's very unlikely the board will get over 50C.
I've cured my boards in 30C with black plastic, and they are still going strong 20 years later. But I've always done it out in the open with ventilation. In a hot confined space it could be an issue.

The amount of water ingress, is affected by board temp change, if it's heating up and expelling air, not a lot will get in. But if it's cooling down and sucking air in, you could get quite a lot.

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Mr Hooper said..
leave it with the vent plug facing down in a warm dry space out of the direct sun.

why down? .. doesn't the hot humid air rise?

I dont know the answer and not saying you are wrong .. just asking.

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JakeNN said..

Mr Hooper said..
leave it with the vent plug facing down in a warm dry space out of the direct sun.

why down? .. doesn't the hot humid air rise?

I dont know the answer and not saying you are wrong .. just asking.

The only chance you have of getting water out is as a liquid flowing out. If you get the board too hot it all just steams up inside and you make an even bigger mess than what you started with.
The reality is that if you get water in your board it will never be as good as it was even if you get the majority out .

Hmm, seems I maybe a bit out of date, post cure heating seems to have gone out of fashion, and there now are a lot of resins designed to fully cure at room temp, albeit at much longer times.
But this Araldite guide is where I was coming from.

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TYPICAL CURE CYCLES
15 h at 50 C
or 8 - 10 h at 60 C
or 6 - 8 h at 80 C
Optimum properties cannot be reached with room temperature cure.
The optimum cure cycle has to be determined case by case depending on the processing and the economic requirements.

Anyway, as long as the board can breath, there's no danger leaving it in the sun, as long as it takes to dry it out.
Epoxy doesn't like UV, but there should be a coat of UV resistant paint protecting it.

cleverku,

As above, get the water out ASAP and your board will be fine . The Boardlady has an excellent guide on this:

boardlady.com/water.htm

In summer, I leave a wick in the board for a few weeks after draining water out (In the shade). In winter time, when the temperature doesn't get more than 15C here, I put board in the car with the windows up.

As soon as I know water is in my board, I take steps to remove it and keep it out. As a result, I've never had a board delaminate.

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decrepit said..
Hmm, seems I maybe a bit out of date, post cure heating seems to have gone out of fashion, and there now are a lot of resins designed to fully cure at room temp, albeit at much longer times.
But this Araldite guide is where I was coming from.

TYPICAL CURE CYCLES
15 h at 50 C
or 8 - 10 h at 60 C
or 6 - 8 h at 80 C
Optimum properties cannot be reached with room temperature cure.
The optimum cure cycle has to be determined case by case depending on the processing and the economic requirements.

Anyway, as long as the board can breath, there's no danger leaving it in the sun, as long as it takes to dry it out.
Epoxy doesn't like UV, but there should be a coat of UV resistant paint protecting it.

Yes, there is a lot of danger in leaving your board in the sun. Please stop telling people to do this .
The problem is that it's ok until it's not.
Post curing is not what we're talking about here. The resin in these boards has gone off, there's no more curing to be done.
EPS fails at 70deg. When it does it doesn't happen slowly. The balls just implode and then your board is fooked.
Let's be honest, nobody wants their balls imploding !

Clenching before a crash will solve water in your vent hole

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I live in Melbourne so about 22 degrees max at this time of year so steaming the water out isn't really going to happen. Beyond inserting a paper towel wick are there any other approaches worth trying (hair dryer, dump some rice in there, keep it in the house instead of the garage, ...?).

I have used a vacuum pump over the hole to reduce the pressure inside the board, same effect as increasing the temperature... Seemed to work, well enough. Only tried it a few times, so have not done exhaustive testing... Don't go crazy on the vacuum!

In your case I can't imagine much water went in unless you used a fire hose

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lotofwind said..
Clenching before a crash will solve water in your vent hole

, good laugh!

I got water in my Goya Bolt board once went out without the plug in, was a light wind day on a foil so just water washing over deck occasionally. Hole is small and kind of hydrophobic (not like there is a paper/cotton lining), was told by Goya support to put in sun upside down, I did that but monitored the board temp. by touching it, once bottom got fairly warm (whitish grey color) flipped over and let top get fairly warm (white with large black areas that got very warm fast) kept flipping back and forth for maybe an hour, never letting one side get hot, just very warm, then used a paper towel as a wick inside house (used chopstick to push in to bottom of board) kept replacing wick as it got wet. That was almost 3 years ago, no problems so far. Unless you hit vent hole head on with hose stream, should not of gotten much water in. Now I always store board with vent plug out, except for when coming back from a session with wet board in board bag, then wait until after I rinse off board at home, to remove vent plug.