marine ply fins?

General Discussion
1

So, I’d like to start working on some fins…

Where can one buy marine plywood in/around san diego? Is that the only type of wood worth using?

Google seems to tell me that marine ply is much higher quality/uniformity than other woods and better if exposed to water…

Hey, fin-builders (blakestah, pauljensen, bert, and anyone else)… what types of wood do you use? experiences? what’s good/what’s not?

I made a bunch of templates with standard plywood…andcouldn’t resist–I started trying to foil one. I can see that I won’t be glassing this one… Oh well, learning experience.

2

i mainly use a 9mm eco exterior ply , marine ply isnt really needed coz your going to seal it anyway when you glass it …

also you want at least 5 layers of veneer for best results …

always have the grain of the timber running paralel with the base , if you dont , then you will realise why you should …

regards

BERT

3
Quote:

{always have the grain of the timber running paralel with the base…}

Bert, is that for the outer veneer layers? Cause, aren’t the veneer grain directions clocked at 90 degrees in most/all plywoods?

4

I thought of using Baltic Birch. It has many more layers than regular ply. Another big benefit would be that it is void free. The only thing that was stopping me from using it was the fact that it wasn’t water proof, but if it doen’t matter I think it would be worth a try. You could buy it at any decent lumber yard.

5

Birch ply is good,as the veneers tend to be all the same thickness, also no voids. It is heavier than a good gaboon marine ply, but probably wouldn’t make much difference even on twin keels. Looks good too with the contrasting colours.

6

I’m curious as to why Bert wants to put the grain of the plywood parallel to the base. When I was a carpenter we always put the grain of the plywood crossways to any joisting to avoid sag between joists. I’m sure there’s a good reason, but I’ve had good luck with pine and baltic birch plywoods glassons with the grain perpendicular to the base. I used 1/4" thick baltic birch on my latest fins (in an FCS setup) which was much simpler as the thinness allows for quicker foiling.

7

I think that baltic birch rotates the grain. One layer is horizontal and the next if vertical. If this is true I don’t think that it would matter which way you placed it. However, I could be wrong.