Hi Guys,
I make my own epoxy sandwich sailboards and have made a couple of epoxy sandwich mals and some epoxy balsa sandwich mals.
I have seen on this web site http://www.carbonart.co.nz/construction.htm that he uses a breathable vent plug made out of Gortex. Does anyone know where these are manufactured? or a supplier?
Prolly an adaptation of something here: http://www.gore.com/medical_membranes/index.html or here http://www.gore.com/divisions/ipd/index.html . W. L. Gore has reps/ offices all over, check some of the other links for further info.
As the stuff ( goretex ) is a thin fabric plus membrane system, I’d probably want to rig some sort of guard or cage over the vent itself, to keep it from getting punctured, or use something that was quickly and easily ( and cheaply) replacable.
hope that’s of use.
doc…
ok this is WAY off topic but for those who live by the beach - there are guitar strings made with a GoreTex coating that last a really long time before corroding, gotta love it! (brand name Elixir as I recall)… talk about thinking out of the box…not having to change strings all the time leaves me more time for shaping !!!
I made a GoreTex vent plug with a brass cap nut and a brass machine screw…
I drilled a very small hole in the cap nut…
Next, I drilled another very small hole lengthwise in the screw…
I cut the head off of the screw…
Into the brass cap nut, I placed a small piece of GoreTex fabric…
I then threaded the screw into the cap nut…
Voila, a GoreTex vent plug…
BTW…It’s not as easy as it sounds…
Ingenious… though we’ve come to expect that from you. and the goretex ( with teflon or something similar in the fabric) acts as teflon pipe tape would to seal the threads. Downright slick.
Drilling down the length of the screw can’t be a lot of fun - and 1/8" IPT bronze caps are ugly, so plumbing stuff is out. Would it be possible to cut some threads on some hobbyist brass tubing of about the right diameter with a small tap and die set?
doc…
hm interesting…the vents i use could easily be adapted to gortex…i had a miner come in and order a board like 10 years ago ,reckons they use gortex for some type of filter in their mining operation,he was trying to convince me back then it would be a good thing for what i was doing…
forgetting your valve , can cause some serious complications with super light eps…i keep getting reminded of the stuff , but still havent acted ,
my concern is it will get damaged and allow water in the board …which will then be our fault…
but if a customer leaves his vent undone and surfs it ,its his fault…
i suppose i will have to try it on my own boards ,i got this one team guy , mr destructo…if he doesnt damage it ,it will work…ill post a pic of one of my vents on this thread , they are real easy to make ,plus the screw is the drain plug from the sump of a mercury outboard motor…so its an available part…
i used to buy them in boxes of 100 but every time i went back for another box the price kept going up , so now i get aluminium ones cnc machined up…
ok ill post pics in the near future definatly within 3 or 4 days…
regards
BERT
I thought that Goretex was only effective when the inside temperature was significantly warmer (like body warmth) than the ambient temp. Anyone else…?
I know goretex doesn’t work very well in cold temperatures, but I guess that’s my problem…
regards,
Håvard
I have been selling paddleboards (Bennett)here on the east coast (N.J.) that have a breathable gortex membrane vent. Its relatively recent technology only a couple of years old but so far no problems. I think Bennett have them made up in Australia and they advertise them as “The Bennett No Nonsense Vent” and it is a Bennett exclusive (at least in Australia) I don’t think they offer them for sale to others because they don’t want their competition to catch up, but if you need one for a one off application i.e. your own board, I’ll look into it if you like.
Gore-Tex
Goretex is a dispersion-polymerised PTFE that is patented by W.L.Gore and
Associates [5]. It is classed as a stretched semi-crystalline film, and is
produced by extrusion under stress ( faster take-up rate than extrusion
rate ). The extrudate is stretched below the melting temperature, often
in the presence of an aromatic hydrocarbon that swells the amorphous region,
creating porosity. The hydrophobic nature of the PTFE means that liquid
water is repelled from the pores, whereas water vapour can pass through.
It is important to realise that once the PTFE pores are filled with liquid
water, the fabric can allow liquid water to pass though until it is dry
again. Thus Goretex-containing fabrics ( such as Nomex/Goretex - which
consists of an outer aramid fabric, a central Goretex layer, and a cotton
backing ) should never be used as protection from chemicals as many will
pass straight through. Any water-miscible solvent ( eg alcohol ) can fill
the pores, and then liquid water can displace it and continue to rapidly
pass through until the fabric is fully dried out.
Also:
Saltwater facts: Salt water does not contaminate, clog the pores of, decrease the breathability of, alter, or harm GORE-TEX® fabric in any way. GORE-TEX® sailing apparel utilizes abrasion-resistant outer fabrics, non-absorbent backer knits, durable GORE-SEAM® tape, and tested and proven garment designs. The result is garments that are 100% waterproof and carry our Guaranteed To Keep You Dry® promise.
Bottom Line:
Saltwater OK
Solvents BAD
More vapor loss when warmer inside.
Related to Paul`s valve construction, but as a Gore-Tex substitute… take a latex surgical glove, cut a small disc of rubber for valve membrane, and then poke a tiny hole in the center with a sewing needle. The hole will remain sealed until excess internal pressure needs to escape. Embarrassingly ultra low tech.
Hmm this board moves fast, looks like I’ll have to start making my own as I can’t seem to find a supplier. The ones that I did see did have a plastic grill type cover to protect them from damage. The only negative I can think about using them is accidentally getting wax in/on them.
I do understand the logic behind the low tec latex valve but please keep in mind that there is a pumping action while the board is used and if the valve is not sealed during surfing it would pump water inside.
hey guys …interesting facts about goretex from rob…
im gonna post pics of the vents i use, ive lined a heap of bits and peices up so you can see how easy they are to make , the aluminum inserts i get machined , but they are a copy of the gearbox sump plug from 8 to 15 horsepower mercury outboard engines…so its a readily available part,all the rest is simple ,you will work it out …
i reckon i could easily replace the rubber disc with a patch of goretex and an o ring …i reckon that would be an easy way of making goretex vents…that way the vent could be serviced if needed,plus still loosened for aircraft travel ,and rapid pressure changes,without stressing the board…
ok hope that helps
regards
BERT
Brilliant! “your an ideas man Bert” Thanks
hey Bert, your valve is as good as they come. excellent.
So Bert… I’m new to the vent idea and will be making an EPS/carbon/epoxy board this fall. The question I have is: Is the plug left open when not surfing and closed/capped when surfing? As opposed to using something like was suggested earlier, Gortex, that would be untouched in or out of the water?
Les
The vent should only be closed for surfing and left open at all other times So when your board is in a hot car or board bag the hot air that is expanding inside the board can escape. If the board is sealed and it gets heated up the expanding air pushes against the skin until it gives way and the board delaminates. I close the vent plug before surfing put the board in the cold h2o for a few minutes then open the plug, as the air inside the board has cooled and shrunk from the surrounding h2o this lets the pressure equalize, close the vent, so that if the board does get punctured it won’t suck as much h2o in.
PS I use the vent plugs made by chinook that can be tightened by hand/fingers(no screw diver required)
But I would still prefer gortex plugs.
Finger tight sounds like a good idea as well as your suggestion of board in H2o/equalize pressure and tighten again.
Do you have a picture? How does it stay out of the way while surfing so you don’t trip in it?
Gortex sounds like a good idea, no messing with it. Any pictures? I can imagine…top of a mason jar covered with Gortex then screw the ring lid down on it. Could probably make something like that using Bert’s(?) plug method.
Les
