Valve your balsa shapes!

General Discussion
1

Hello gentlemen,

 

Haven't been on in a while, but... I recently finished a 7'5 balsa single for myself. Retroish, round pin, a nice all-arounder from a Shark Bay blank.  Usually, I only use glass-ons on my balsa shapes, but as this one was for me and I like to play with fins, I decided to go with a box.

Fun session (with Pierre) yesterday in fun head-high conditions.  The board went great, not just no complaints but plain stoked.  Hurry back to the car as we're running a bit late (one more last wave, of course...) and rush to pick up my son.  Get home on time, then as I go to pull the board off the racks, I hear a dreadful sloshing sound.  Double take.  Move the board - slosh.  Move it again... slosh. I check for unexpected cracks and nothing shows up.  Then I check the fin box, and of course, when I turn the board its leaking like a seive.

So I drill a hole in front of the box, and one in a rail juncture to allow the water to flow freely, and I drain about a litre of water out of the board.  Later, as I'm shaping a filler plug for one of the holes, I notice that between the moisture and the high temps yesterday, the skin has detached from the frame along about 18" near one rail. Not enough to rupture the glass, but enough to give me a 1/16" to 1/8" rise in my bottom contour. Shit.

So, tomorrow I'll have to sand the section down to wood, figure out how to glue and clamp the zone... and then get after my glasser about the box install and pass it back to him to glass the repair and reinstall the box. Shit. Almost makes me wish I was still glassing.

Lessons to be learned?  Make sure that your glasser installs the box per instructions! And, for goodness sake, valve your balsas! I haven't done so in the past (maybe 20 balsa shapes as of now?) and have never had an issue before, but his one has me convinced!

Anyone have a decent brass valve that they'd like to part with? I'm now officially in need.

Mahalo,

 

 

2

Hi Jeffrey -

I used Shark Bay for a balsa blank but it was solid.  Was yours chambered?  You say it detached from the frame.  Maybe it was a hollow wood plank-on-frame?

3

Hello John! Hope all's well on your end.

Plank on frame is exactly it - makes for a nice weight blank. I have travelled with boards using the same blanks and construction, and even with air travel have had no worries. This is a first for me - probably due to the extremely warm weather yesterday and the quantity of water inside... maybe a 40 minute car trip with the board on the racks, in a board bag, was all it took.

Any insights?

 

4

Was your board inside glassed Jensen stile or not glassed Grain stile.? The balsa is wet, your going to have a mold problem which will turn into wood rot. Take the fin box out so you have a big enough hole to get the inside dried out. Bleach inside should kill the mold but you are realy going to have to get it dry, I mean real,real dry. If it isn't completely dry you are going to have a condesation issue and in time the balsa is going to rot. I would take fin box out , bleach, drain it good then stand it in the corner of a dry room for a couple or six months..When you know for sure it is dry then you can repair fin box and any glassing. Why did you job out the glass job ? If you built the board and then had some one else glass it then you are only half way to being a wood board builder ! A surfboard shaper is a shaper ! a glasser ins a glasser ! If you don't do it 100% yourself then you aren't really a wood board builder.

5

I have dried out wood boards by putting them in a closet with a dehumidifier and a fan.  I try to know what the original weight of the boards is, so I can weight it periodically while drying it out to determine when there is a little or no water left.

I helps to have 2 holes in the board when drying it out, so the air can travel through the board. 

Also, once the wood dries, the bump may go away.

Hope this helps,

Mark

6

Thanks for the insights - The fin box will get pulled today and the board will be set aside to dry for however long that takes. I hadn’t thought of bleaching the wood to disinfect it, but thanks for the tip. The bump may drop back into place without the moisture, but there is definitely a separation from the frame with a split in the wood, so I’m not banking on it. 

As far as glassing goes… I would have agreed with you a few years ago but my reasons for stopping glassing are in the skin cancer thread. Some radiation treatments already later this summer, and I don’t need the extra fumes at this point. Maybe I should have said valve your balsas and wear your masks! No offence taken and not to get heavy on this. I 'd actually love to still glass my own wood boards.

I’ll post when I yank the fin box later on and let you know what failed on the install. I have a suspicion, but want to be sure.

Still in need of a brass valve if anyone has a tip? Or I’ll go the Pierre method and modify a radiator valve…

 

7

 

Are you sure about that ?  I thought salt water prevented wood to rot.  

Some traditionnal wooden boats that stay in fresh water are protected from wood rot by putting salt on their wood structure.

8

Salt attracks moisture and the fluctuation in temp inside the board causes condensation which is fresh water. But you are right up to a point. The salt water will slow down the rot issue a lot. But we are talking about balsa wood here not white oak or other durable wood. I only have to look at the board next to my desk to know exactly what is going to happen !! By the way the clorox bleach mix is 10% and is not allowed to sit inside the board as clorox will in time destroy balsa wood.

9

I bleached (though my mix was about 20%) and then hit the interior with 35% hydrogen peroxide, which I’ve found to be really useful in killing all kinds of mold/fungus in the past, especially on wood.

The weak point was indeed in the box installation, the sides were well reinforced with 6oz but the front end was not, and with the difference between the air and water temp, it didn’t take much of an opportunity for that water to slip right in.

Once it’s all nice and dry, I’m going to try and reglue the deck to the frame from the inside with epoxy, then clamp her down and let that set up. Otherwise that bump/weak point is going to bug and worry me. Followed by building a more solid framework surrounding the box by going through the routered hole.  Then we’ll close her up and get this thing surfing again!

I’ll keep you posted as that develops.

An interesting learning experience…

But I think the 9’2" I’m starting will be a glass-on.