Hi I’m about to start my first balsa board and I’m planning on making it chambered. I know the the hollow Jensen style boards have valves on them but don’t know if the type I want to build (with many small chambers) needs them. Do I have to worry about pressure if the chambers are small and not connected to one another? If I do need them, would I need one in each chamber? That seems like it would be wildly impractical. Also, I will probably be taking it on a plane at some point. Don’t know if the greater pressure changes makes any difference. THANKS!
I’m in favour of a valve even on solid balsa boards. . . . my favourite 12’ solid balsa board (with no valve) suffered from delamination of the glass from the timber which I suspect was related to internal pressure. . . . this only happened after several years of continuous use and abuse. . . board stored outside on roofracks (uncovered) or left lying in the grass during sun and rain, winter and summer. . . also surfed at least once a day on average, dropped, hired out, and run over with a truck.
I’m not sure how many classic Velzy’s get abused in this way but I would be interested to know if anyone has a solid unvented balsa in daily use without delamination. My board was also flexible which might have been part of the problem, so I’m just guessing about the vent, but I know that if the board got a ding it would suck and blow through the ding as the temperature changed. . . in fact I used one small ding as a vent for a long time, and when I fixed the ding the deck glass lifted soon afterwards. The moisture content of the balsa could have been a factor but then again timber in a board always has some moisture content.
Here’s the vent we use for hollow boards, it’s easy to operate without a key.
Maybe those boards are looked after pretty well. . . mine wasn’t.
Didn’t know that Velzy made extreme pintails
Here’s a chambered Balsa ‘workboat finish’ extreme pintail. . . . a plain Jane but it’s seen the inside of a few waves ! . . . . . . . . . and no vent either :0
BTW didn’t Bert say that a vent is needed with his boards for high altitude e.g. air travel?
Wood itself is porous, so if you do need a vent, you would not need a vent on each chamber - unless you were planning to use somethig to seal the inside surfaces of the chambers.
thanks for all of the suggestions guys. I think I will play it safe and install a vent. It doesn’t seem like there are really any disadvantages to having one.
I think your answer depends completely on what the board will be used for. If it’s a wallhanger, why bother - keep it clean and gloss it with poly for that “look”. If it’s a frequent rider, maybe you should chamber, depending on how you chamber. The vent will only vent the chamber it’s connected above, so you’ll have to have at least a small hole connecting all chambers. Wood expels and takes on moisture mainly through the open cells of the endgrain (like microscopic straws), but the wood cells won’t transfer air or release pressure from one chamber through the wood to another chamber, especially on a hot day when the board is left on the car for only a half hour or so.
Delams on balsa occur mainly due to the fact that poly resin doesn’t like to adhere to wood. I have a multi-redwood stringered balsa hanging high in my shop which gets really hot in summers. It has developed several cloudy delam areas mainly on the redwood stringers and rails. The multi-stringered balsa in the house has absolutely no delams. Same glasser, done at same time, and glassed the same. If you epoxy it and leave at least 1/2" above your carefully executed chambers, I’d say you don’t need the vent. Your vent could do far more damage to the board if it’s not installed perfectly or left open by mistake, than not venting would likely do.
