I wanted to change fins on a Starboard Sonic (bolt through fin box) yesterday but the weed fin wouldn't fit in all the way - the fit was too tight - the fin was about 5mm shy of flush with the bottom of the board.
Any ideas?

Was it a flying objects fin?, my mate bought a new weedie yesterday and it wouldnt fit in his futura.

Find yourself some material to paint over the sides if the fin base (water colours from kids will do), something that will come off. Put the fin back in and tighten, loosen and remove. The area that has the paint removed by installing, is the high spots/points, sand those back a tad, then retest til your happy. Be careful you dont get to excited with sanding, and sand it back too far.
You can use a high lighter or any item that will show high spots.

A slight addition to Minerals good advice. The front of the head is usually longer than the back, so I normally work on the back, (it's less sanding)

I've had to operate on a few tuttle fins like this, and it's usually because the base is a little too long for the box.

Sometimes it's all at the edges, (the fin box is rounded but the fin is square).

Mineral's method will show this up. Try to keep the back vertical edge straight or slightly hollow, if it's convex, the fin can "rock" a bit and not seat properly.

If it's a power box, there's the added complication of tapered sides as well as ends. I've never done one of these, but the same theory should apply, you've just got to check sides as well as ends.

Thanks Mineral, job done successfully, took quite a while though, using your very careful approach.
Tuttle box, and the tightness was at the sides, not the ends.
Now fits snugly but flush with the board.

Vic, it was a leading edge fin.

You have a LE Weedy... Wow... Lucky you

a few years ago, I believe the size of the box decreased slightly from boards coming out of cobra factory

Nothing wrong with a good tight box...

Edit: oh i skipped over the fin part

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silvec01 said...

You have a LE Weedy... Wow... Lucky you
are they especially good?
That's the one that "Santa" dropped off on my doorstep on Christmas Eve...

a few years ago, I believe the size of the box decreased slightly from boards coming out of cobra factory

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Windxtasy said...

Thanks Mineral, job done successfully, took quite a while though, using your very careful approach.
Tuttle box, and the tightness was at the sides, not the ends.
Now fits snugly but flush with the board.

Vic, it was a leading edge fin.

Well done
I was going to mention that another way I have made them fit is with a rubber mallet but only in desperation until I could get the sanding part done. Only had to get it in the last 2-3mm Was a bugger to get out, even though I had sprayed it with fish oil

Just a hint use a file (bastard file) not sandpaper, especially if you have to do the sides. The sandpaper (even with a block) tends to sand the whole thing not just the high spots, whereas a fille just gets the high spots, takes minutes rather than hours.

Happy sanding.