Yo! Checked the back logs and maybe I missed a good thread or two. But I wanted to make some wood fins for quads and thrusters. Is there any thoughts on wood properties- flex, weight, strength? As well as glassing techniques for- flex, strength and weight? The combination of the two seems like there are an endless possiblity of variables. Fins would be for high performance boards. I know there are tons of functional plastic, fiberglass, and carbon fiber fins, but some classy wood fins would just look old school Chris Craft kool!
Stiffest fin will have all the grain alligned along the angle of the rake. Flexiest/weekest would be with the grain at 90° to that. You could use veneer to layup your own plywood and customize your grain angles to your need also. An advantage to multiple grain angles is resistance to twisting/shear off of your fin. Many people use marine ply that you can get at hardware stores.
fin wood should have straight grain free of knots. shaping knots is a real bitch.
low density wood that is easy to work is a plus - pine, balsa, mahogany, cedar come to mind. Fir species often have too much density difference between growth rings and summer wood.
wood should not be oily such as teak.
really hard woods will look nice but are hard to work
plywood layers and glue lines can look nice but beware voids in less expensive grades with few layers. birch ply is cabinet grade and works if you have it
the flexiness will largely be removed by the layer or few you glass 'em on with.
A nice thick halo at the leading edge greatly adds to fin longevity if there are any sort of rocks or reef in your locale.
fix holes in wood fins really quick or they soak water, grow rot and stain black
tools: block plane, hard pad 40-60 grit on the grinder, 60 grit on hard block for most hand work.
A center section of 3 layers mat and tinted resin, with two layers 1/8" lauan ply outside provides good leading/trailing edge stiffness yet most of the foiling is easily done in the wood sections. Looks nice later too, but most of the wood that shows will be the middle of the lauan, so think about the grain that will be exposed when you cut it prior to laminating it.
If you have a band saw you can piece together amazing bands and patterns. look up some of the old 30- to 60-piece fins. Light and dark woods can make beautiful patterns.
Awesome. What I was planning, was shaping a solid peice of … with bandsaw, router, grinder, orbital sander and finally the details by hand and file. Thanks for the wood selection, that will narrow down the woodsn. For the first few, I’d like them to be functional. Then once I’ve got a pattern I’ll get all artsy fartsy with different wood colors and stains. I’ll post some pics once a few are in the bag.
