Balsa longbaord finbox install

Nice to be back - I haven’t posted in ages as I haven’t been shaping with some health issues that keep me away from resin and foam.

But, the bug hit me the other day and I got out a nice balsa blank that’s been sitting in the garage for a couple of years.  Shaped a nice 9’3" round pintail longboard, fairly progressive, and I have a perfect 9 3/4" 4a style fin that I have in mind.

Traditionally, I’d just cut off the base and glass it on.

For some reason though, I’m pondering a fin box on this one. Heresy, I know, but I’ll be hanging onto the board and may want to play with fins at some point…

Anyone have any longtime experience with boxes on balsa? I’ve done a couple of eggs with boxes, without any real issues though in most cases I only kept them a year or two before selling.

Insights are welcome, thanks!

The board in question.

The problem is the inside of the board at the fin box position. (I think your board is chambered and you chambered the fin box area too, right?) I like to leave this aerea solid and then its quite easy to route a slot and glue in the finbox. (I do HWS and reinforce the stringer to a width wider than then the box, and after gluing deck and bottom I just route directly into it).

 

If it is as described, I would route a slot in the area at would glue a solid piece of balsa (larger than the finbox) from the bottom onto the deck from the inside. and in a second step, I would route the slot for the finbox itself. 

the box in the pics is finally covered…



Thanks.

I’ve got a solid piece in the fin area so the install wouldn’t pose any real issues structurally.

I do like the cover as you did it. Balsa Bill did a super clean one years ago that he posted on here. That could be an option for the esthetics…

Every had any issues on the installations in your hollows?

 

 

Never any issues! The problem with covering is to get a very clean cut cross the fibers. I wedged the top layer, but when I sanded it to match the deck, the glue line got a little bigger. If you cover the entire board with a veneer, covering is much easiser. But in this board I set the box a little to deep, thats why I tried to cover it with balsa. 

Below is a veneered covered finbox…

Nice work Gentlemen.  Yater has always done the nicest balsa on the West Coast(imho).  Your boards are better.

Very clean, nicely done!

 

Thank you!

 

This is my last one, almost finished, wait for higher temperatures to give it a final PU varnish coat. The veneers are striped, tiger?, maple and eucalyptus

see: 



 Shaped a nice 9’3" round pintail longboard, fairly progressive,

I love the shape - anything special or interesting on the rails and contours? (belly, concave, V, etc)

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I agree.   Especially nice outline at nose and rounded pintail.

Thank you, gentlemen.

This one is pretty straightforward. Lowish rails that gradually harden to a sharp edge in the tail, slight concave to vee, just a nice all-arounder. I usually shape my balsas this way since the boards last, and this combination has proved itself over and over again.

In the end, I decided to go with a glass-on. Just couldn’t bring myself to install a box.

I’ll post during or after the glassing phase!