I’ve seen the Aviso leash plug vent, great idea and well disguised but still open to error by a forgetful user.
Your idea takes it to the next step . Well done, when can i get some in Oz.
Cheers
Mooneemick
As one of the earlier people to get ahold of these vents for testing purposes i thought i would chime in here. I picked up a few this past summer after meeting Brian at his shop in Philly. I told him i was building a couple of compsands and we got onto to venting. He then pulled these little gems, new vent/leash plug combos. They were still in prototype stages but still blew me away. I had been previously installing goretex vents that were a little larger and still needed a leash cup install also.
Installation in quite ingenious, and easy, but that is far as i will go. Lets just say he explained it once, and it would be hard to screw up after that. Brian can explain more when the time comes. Following some simple instructions of being careful when installing the leash loop, and simply washing off salt water after use, i was on my way. (Along with a box full of other goodies)
The vent was intalled on a compsand fish, that has been used since august. There has been no signs of water leakage in and around the vent. The board has sat in cars that went well above 80 F to water at 55 F. From my inspection, these are legit. I will be purchasing more for every eps and xtr board i shape.
Its good to hear these are coming out soon to the public. Merry christmas everyone!
…im not sure how far Brian is in releasing these vents, or for legal matters, i will hold off on a few build pics that i have of it.
Dave
Sorry guys,
I really don’t want to seem like I’m looking at the glass half empty, Ive just seen enough half-way
engineered products come and go.
I’m really trying to look at it from an engineering perspective.
I think some more thought should be put into the concept first. I’d also like to know how they tested the
product. Maybe put two identical boards in the same hot car and telling us how one survived and one didn’t.
Add into the design a way for trapped gas to travel to the plug. The gas is generated throughout the
entire board. so give it a void to travel through to the plug. Rout into the blank, one top,
one bottom, a hollow carbon tube (think fishing rod or firewires direct drive )with small holes perforating it.
let the gas travel through the tube to the vent. Otherwise the damage will done before the gas
finds the vent. Remember, we’re talking about EPS, not Aviso hollow.
Now that I’m really going on it, what about parabolic tubes, connected to the fiberglass skin.
They could replace the conventional stringer. Stiffness could be modified by changing the diameter of the
tube.
Lots of other ideas about it that would make it viable. My fear is that someone is going to convince
the next group of guys that this plug will save their boards, while really letting water in.
Why doesn’t Otay spill it on what the failure was in the factory he work in. Surely telling about
the complications of a failed product for the backyard guys. "Two major concerns with the leash plug
vent that will be discovered soon when the back yarders get their try at them".
Again, sorry if I seem like a stick in the mud.
I’m just pissed because Brian didn’t tell ME about it!
I’m just kidding…sort of…
Good work Brian…lead the charge bro!
Sorry Everysurfer, but you’re trippin’ just a little bit 
EPS definitely allows air to pass through!
Unless you are using the super fused stuff, and then you won’t need the vent in the first place.
Goretex have passed their IP rating, IP69K from memory.
They are up to the job, but that doesn’t mean that there won’t be the odd one that fails, these things happen, nothing is ever perfect.
It’s an excellent solution to one of the weak points of EPS.
OK, here we go again with the whole vent issue: (1) I’ve sold Gore-tex vent kits for the past 3 years and all of the originals are still in service without any problems. They’ve been used all over the world in harsh conditions in eps, compsands, and hollow wood. (2) Placement is important. You want it at or near the widest point. My original concept was at the rear and also in a center finbox, which doesn’t work very well if the only the nose is in the sun heating up. (3) Smaller boards need larger venting area than LB’s or SUP’s. (4) Whether or not you use a vent is your own choice based on your experiences with eps boards. The major labels I sell to have had numerous problems with delams and such, and these were eliminated once vents were incorporated. Most failures were about 2% per 1000 boards; so a high volume is needed to really see the problems. Also the need for venting during lamination in high temp or when heat curing is becoming very apparent to most larger glassing houses this winter. Everyone will agree that any hollow-core needs to be vented, but why not eps since all are about 97% gas in volume?
I’ve explained in detail in previous posts the mechanism of eps expansion at both altitude and high temp, and also why D-cell skinned boards have some immunity to this. Those interested can look in the archives. Also to answer the question on polyboards, they can’t be vented because there are no air spaces between the cells.
Most problems with vents are the vents themselves. The open/close screw types are either left open or closed when they shouldn’t be. Some try to make their own vent using the Gore-Tex material, but reliably sealing the edges 100% is another story (many FireWire owners can confirm this). Another board manufacturer drills tiny holes along the rails.
Aloha Pete - wanted everysurfer to get the answer he needs to hear. The vents work perfectly and if you haven’t experienced a delam on 1.7lb. or lighter eps with a nice dark gray bottom then I don’t think you actually are in the surf ind. - do you even build boards?
Here is the answer - a rider has left his board in the back of his truck twice getting huge bubbles in the bottom. Both times I fixed it and told him don’t do the sun on the black bottom. The third time I put in one of pete’s vents and told him go ahead -roast the bugger. He has ever since left it in the sun - we are talking six months everyday surfs and in the truck dawn to dusk. This guy surfs three times a day most days and never again a delam or bubble since the vent 6 months ago. The air pressure is released from both sides of the stringer - it passes through the foam like nothing.
If you work with eps you know it’s just a bunch of air trapped in huge beads - vents work period.
Hi Pete -
Have you been able to determine if there are specific EPS foam densities in which the vents are necessary or in which the vents are no longer effective?
Awhile back I posted a basic experiment with “windows” cut in a vacuum bag that showed higher density EPS not being permeable to air flow through the foam - at least at vacuum levels tested. The lighter density seemed to allow plenty of air to pass through.
“Unofficial” conversations with industry folks have led me to believe that densities 1.5 lb/cu ft was kind of a dividing line between vents vs no vents.
Are the tiny holes in the rails for XPS foam? That foam doesn’t seem very permeable to air flow either.
Anyway, just curious on your take. I have searched the archives and have yet to find a consensus on which densities need venting.
Hello John - I’ve done lab on testing with the normal densities (1-2 lb), and also math models with the higher densities. Both confirm if there is a potential for the board to reach a surface temp of 110 F, they need to be vented. My modeling uses equilibrium states, because it’s much easier than a time-related analysis because there’s too many variables changing at once (I ain’t doing no more differential calculus). So, I can’t track the temperature rise to a specific time when critical expansion would occur. In my opinion, knowing the temperature is enough.
You brought up a good point about air permeability in eps; i.e. the spaces between the beads. When the beads expand because of heat, the air spaces will also expand because of the increased pressure on them. The air pressure will flow looking for a path of least resistance like towards a vent. Test samples that where subjected to very high temperatures show this flow path when cross-sectioned. What you get is flow channels that develope larger in the heated area and decreasing in size nearer to the vent. This tells us is that closely packed beads with little air space will change in structure vs. foam with larger air spaces when heated and after recovery when cooled.
Very small closely packed beads still must conform to density standards. It’s still 1 or 2 lbs per cu ft, so there’s even less styrene than common beads and more blowing gas. This is why xps and the like are more reactive to temperature. So what good is this stuff? Many boards made from this feel more “alive” because you’re riding a shell filled with more gas. Because of the sealed gas, the whole board is like a hydraulic spring. The second reason this type of foam is around is that somebody thought that it would have less water absorption (entry via the air spaces) or that it was stronger. As insulation material, these two things have a degree of merit, in surfboards no. There are very few (if any) blank suppliers who actually make the beads and mold them specifically for boards. Most blank suppliers cut block eps and stringer it. They do not have technical resources like Dow or the others that actually make the beads. Whatever question they answer is likely an opinion or guess.
I also want to commend everysurfers skepticism as a consumer. I’ve been involved with some of the largest manufacturers in the surf industry, and I can confirm that there is no real design engineering there at all. I’ve spend hours answering questions about all kinds of stuff for them free, maybe because I’m used to doing that here. What I got back was ripped-off ideas that were capitalized on, info that was used to leverage their competition, and their usual arrogance that they know everything. Coming from the medical and aerospace fields, I would never put products in the field to see if they actually work, and I don’t think anyone else should either; even if it’s just for surfing.
My apologies…I believe I referenced DanB when I meant PeteC earlier.
Hi Pete -
Thanks for that explanation. I had not considered what happens when the foam is exposed to heat but the path of least resistance under increased pressure makes sense.
I recently bought a couple of 2.5 lb/cu ft EPS blanks that appear to be well fused throughout. Would you advise that they be vented?
A board made a few years back with 2.5 was left unvented and no problems (so far.) I have not measured surface temps after the board (yellow) was left in the sun but 110 degrees seems reasonable. Dark colored boards likely get hotter.
US Blanks and Marko mold their blanks but I’m not sure they make the beads.
Pete,
A thought I’ve been having on EPS for a while now. Is the gas in EPS expansion inert or reactive?
My concept is, will the gas will react with something and form a percipitate. The reacting element
could be added as a skin over the EPS and under the epoxy. When the gas forms, it would
react with the skin element, and solidify.
I guess the trick would be to find a reacting gas to use in the expansion process. and then post
expansion, add something to either absorb or solidify the gas. Could be as simple as a carbon
filter layer to absorb it.
It’s been 28 years since college chemestry, so its all way over my league.
Thanks,
Mark
(Everysurfer)
Mark, The blowing agent for almost all US produced eps is CO2. CO2 is a reactive gas with some elements but not others. However, the problem is not out-gassing from the blank, but just an issue of volumetric expansion. The beads/cells grow in size, the air expands, and the blank volume changes. A vent allows the expanding air to escape which in turn creates space for the expanding beads/cells; thus no volume change. The only other way to address the problem would be to insulate the core or cool the skin. D-cell over the foam acts as an insulator, and light, matte colors will keep the skin cooler. Both of those solutions are very limited though. Epoxy is a direct heat conductor, and there is no thermal boundary (air gap) before the foam in a normal lamination. So a nodal skin temp = underlying foam temp almost immediately.
John, the technical answer to your question is if you keep the same construction and conditions in climate and altitude, you may not have any problems. The answer to a friend not wanting to take risks with his board is yes, vent it. The screw-in types are only $3 from Fiberglass Supply and easy to install.
Solar loading is the fastest and primary cause of heating, and will vary with latitude, humidity, ambient temperatures, wind conditions, and the time of day. In So CA, these factors are pretty optimized during the summer and eps problems are more common here. Unlike solar hits which can quickly affect an isolated area, ambient heating will take longer because the entire board must heat up to a uniform temperature before it can start rising to a critical level. This would be in a curing oven, hot car, or during air transport.
Pete,
I have 4 of your vents in use and I’m super thankful for them. Like I said in an earlier post, I have seem them expelling air while the well is full of water. My boards all get a lot of use and they each get weighed on an accurate scale every few months. I have had zero problems.
I have left these boards in a VERY hot car, I’m talking 125+ degrees F (110F Outside Temp) a few times. I paid when I made that mistake in the past, but not since your vents are in. I know for these vents saved me a few hundred dollars and tons of aggravation.
I can appreciate some worrying about the vents leaking or failing. But for me, the fear that hits when you feel how hot your car is inside is way worse.
By the way, boards are 1.5lb EPS laminated with Airex, Divinycell, or Bamboo Veneer
I post cure my boards at 50 - 60 degC (122F - 140F).
If a board is vented, it is no problem.
That is with epoxy/eps/wood.
One way you could have a problem is if you ramp the temperature up too fast, especially in a localised area.
This is unlikely to occur naturally, but I could make it happen with my heatbox.
I think everysurfer has a healthy scepticism of engineers, but the fact is that this solution is better than the alternative, which is risking delams, or boycotting the tech altogether.
Both of which would be a crying shame.
Go with the best solution on offer at one time. Sure it may have some flaws, but it’s still the best solution there is.
Except for some secret sauce that I have in the works… and a entirely new core solution that is in the design phase
CDD doesnt require vents either
if you could get hold of one
1 pound foam no vent
ok then
what happens when the beads expand and the air inside expands
certain amount of pressure and what?
it pops a pinhole somewhere near a plug perhaps and the board slowly fills
or does it balloon and pop the skins off
or does it balloon and the beads shear off from each other
what actually happens and why
why do the skins pop off
surely the epoxy/ bead bond is more then strong enough, maybe its the beads that fail
what if you cut the blank lengthwise throug on the horizontal plane before laminating
so when it balloon it seperates from the center of the core
i dunno
soes anyone actually know whats happens
Interesting and timely… I’m doing a 1lbs. EPS and corecell board right now. Cut out the
template testerday. Nice warm sunny day. I use full sized paper templates that
I print out on my large format printer.
This morning it was about 50 degrees, cold and rainy. A low pressure front moved
through last night.
I was reusing the full size template to cut out the corcell. When I matched
the two foams up, I noticed the EPS core had expanded. It had grown
in length 1/2" No chance of mismeasuring because I still had the original
paper template.
Low atmospheric pressure causes EPS to continue expanding.
Back to your post, there must be outgassing of the blank, or there would be
nothing to vent. I thought the delamination happens when gas builds up between the
Foam Core and the Epoxy skin.
If the gas used is CO2, how about adding clorophil internally. Talk about going green!
That might absorb the CO2. Either that, or what chemical is used in diving re-breathers.
But then again I could be totally wrong.
The gas between the beads is just air.
The gas within the beads is fully sealed in there, to most intents and purposes.
It’s just the air between the beads that comes in and out of the vent, moving due to pressure differentials caused by temperature.
I like your out of the box thinking though!
Keep on throwing ideas out there, it’s definitely the way to strike upon new solutions.
Quote:
It had grown in length 1/2"
It’s clear what’s going on here…shop gnomes fixed your template last night.