It's bad enough that there's all these different types of fin boxes but even if you get 2 which are supposed to be the same they are not.
just got a fanatic falcon with a deep tuttle box and planned to use the 4 nice carbon fins I already had which I use in my ultrasonic but oh no. It turns out the box in the falcon is narrower that the ultrasonic so I now have to sand-down all my fins to fit the falcon and have them loose in the ultrasonic. Very annoying.

How much narrower?

what about sanding the inside of the box? maybe is has a little too much epoxy resin on the outside (inside).

^^^^
+1
As long as your not trying to fit a deep tuttle into a tuttle box .

Be careful trying to adjust the box internally. It's very easy to make a mess of it so nothing fits well in it.
I imagine it's only a ****teenth of a mm out. It should be fairly easy to adjust your fin base width enough to fit in the dodgy box and also fit in the old box. A lot of the support comes from the front and back edges of the base. Worse case scenario is you may have to shim it slightly for use in the loose box.

My falcons with foil box had same issue, but the other non foil box sizes were all normal.

Select to expand quote

Sandman1221 said..
what about sanding the inside of the box? maybe is has a little too much epoxy resin on the outside (inside).

sand it inside using a flat straight piece of wood with sandpaper attached to it and slide back and forth keeping even pressure top to bottom, should not take much, keep checking after every 5-10 passes on both sides of the inside, want to remove same amount from both sides to keep fin perfectly centered.

Select to expand quote

Sandman1221 said..

Sandman1221 said..
what about sanding the inside of the box? maybe is has a little too much epoxy resin on the outside (inside).

sand it inside using a flat straight piece of wood with sandpaper attached to it and slide back and forth keeping even pressure top to bottom, should not take much, keep checking after every 5-10 passes on both sides of the inside, want to remove same amount from both sides to keep fin perfectly centered.

Inside your fin box there is no external filler coat or gel coat. You will be removing fibre and the overall integrity of your fin box as soon as you start.
If you do manage to get it right first go, well done. If you don't get it right you've just stuffed up your fin box and seriously devalued your board.
Much less room for error and easy to correct if you adjust your fins.
Good luck !

There could be something wrong with the box . A repair ? As Mark asked , how much are we talking about ?

Select to expand quote

Ben1973 said..
It's bad enough that there's all these different types of fin boxes but even if you get 2 which are supposed to be the same they are not.
just got a fanatic falcon with a deep tuttle box and planned to use the 4 nice carbon fins I already had which I use in my ultrasonic but oh no. It turns out the box in the falcon is narrower that the ultrasonic so I now have to sand-down all my fins to fit the falcon and have them loose in the ultrasonic. Very annoying.

Have you tried putting a fin which fits the Fanatic in the Starboard to see where it is different? If you have one.
With my recent foil tuttle box, I found the length of the box was the issue, not the width. I only found out for sure when measuring with callipers at the shop before sanding.

Select to expand quote

Mark _australia said..
How much narrower?

About 2 thicknesses of plastic bottle.
length is good

You should really use a more technical measurement system.
Id say that's about a bees dick and a half.

Select to expand quote

Ben1973 said..

Mark _australia said..
How much narrower?

About 2 thicknesses of plastic bottle.
length is good

so about 6 inches?

2 thicknesses of a plastic bottle is a lot . Something is wrong . Did you buy the board new ? How old is it ?
If you have to remove 2 plastic bottle thicknesses off a fin to fit , it will be ruined for normal boxes . It would be like throwing a sausage down a hallway .

Select to expand quote

Imax1 said..
2 thicknesses of a plastic bottle is a lot . Something is wrong . Did you buy the board new ? How old is it ?
If you have to remove 2 plastic bottle thicknesses off a fin to fit , it will be ruined for normal boxes . It would be like throwing a sausage down a hallway .

Agreed, that is a lot . A bit like xxxx a gumboot full of porridge.
I can't imagine it's that far out, that would be around 2mm.
My guess is the fin box mould was machined slightly too small and they haven't caught the issue before it went into the board.

Agreed Hoops its massive. But we'd have heard about a number of faulty boxes by now.... and that sound like a major variance.

I'm wondering - Ben is there a lip around it? ie: the glass was not cut back flush to the edge and the box is therefore OK but the entry is tight?

I can't see a popular brand board suddenly having a box that's 2mm narrower and no normal fins would fit

Check it with a Vernia gauge. Plastic bottle thickness isn't a very useful measurement. I very much doubt it's 2mm. .5mm is enough of a mistake to make a big difference.

Yeah , even half a mm is huge. The difference between tight and rattly would be 0.2mm .
I've used 1 layer of packing tape on each side to temporarily fix a rattly fin . Tape is only three fifths of fark all thick . That's only one third as much as a bees dick.

even a bit of paint over spray will make a box too tight.

Been using Falcons for over a decade and pretty much every fin Ive had fitted straight in. If anything Ive had to shim a few.
Techtonics, C3, Kestrel, MUF, Flying Objects etc. Doesnt sound right.

Select to expand quote

decrepit said..
even a bit of paint over spray will make a box too tight.

Yup. Careful at the tanning salon.

Select to expand quote

ka43 said..
Been using Falcons for over a decade and pretty much every fin Ive had fitted straight in. If anything Ive had to shim a few.
Techtonics, C3, Kestrel, MUF, Flying Objects etc. Doesnt sound right.

Larko, depends on the fin make. My Black Projects fit but my Tribals and Atomics don't. However a hand sanding on the sides of the head with 150 grit paper and it's all good.