The archives have been able to answer most of my questions as I have struggled through my first two board-builds. But, this was my first time installing futures fin boxes, and, I think I’ve put myself in a semi-tough spot. I’m hoping that the sage craftsmen on this forum can bail me out. I haven’t seen this posted on the forum yet; I apologize if I’m asking an old question.
Here’s the problem: The holes I routed for the 3/4in deep side fins (thruster setup) are a bit too deep and I’ve already glued the boxes in place. The top of the lip on the fin box is 1-2mm below the bottom of the board, so, I’m concerned that I won’t be able to grind down the tape and glass over the box to re-expose the box. I naively tried to do the fin install after laying down 1 layer of glass, so, I can’t just sand down the foam around the route. Any thoughts?
Will the glass conform enough to the divot I’ve made to allow me to grind/remove the glass over the box?
For the divot, should I just try and cut out pieces of glass to fill it?
Bigtree, i’ve done about 3 futures installs so far, and they all have ended up being routed out a bit deep. I just been filling up the void with lam resin until its flush with the foam and glassing as usual. Theres still been plenty of the box left on top to grind down, and havnt had any issues with them so far. Would think u might get a lot of boubles if u just glass over the gap, and already having a layer of glass down might be more problamatic too?
So you glassed the bottom of your board, routed and installed the Futures a little to deep, if this is the case cut your 4 oz patches and lam them over your boxes getting out all the air bubbles. If your using uv poly or just poly for the hotcoat tilt the nose down a little so the boxes are more level in the back and kick it hot or get it out in the sun there will be less draining around the finbox . If your using epoxy, hot coat as usual, have a little left over or take it from where it is dripping off the tape and as it start to gel pour the leftover epoxy back around the sunken finboxes this way it will come out level. Sand as usual and you should be fine.
For the next time(s): When you route the future holes, it is important to test-fit a box before you remove the jig, so that you can get the route right. Pushing down on the router can get you a bit more depth if you're shallow on the first pass. And you also want to make sure your router is adjusted correctly first, test on some scraps before going on to actual board.
Once you've gone too deep and have the boxes tacked in, it is a PITA. Filling with lam resin is going to be brittle and prone to stress cracks down the road. If they are so deep that they don't sand open properly, you may have to dremel them open or something (and there can be fin fit problems after).
I take it you are using the Ryobi trim router? In which case before next time drop the router to its full depth and then slide the shaft of the bit far enough into the collet nut so it is the correct depth.
You should end up with a least a third of shaft of the bit extending back into the collet nut. That way for next time you don’t have to worry about checking the depth of the router.
Do check that the bit hasn’t come lose or sunken further into the collet nut before proceeding routing though.
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Once proper router depth is achieved, mark the router body for the future uses.
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Hell, I'd like to go one step further and weld that sucker in place. Trim routers are cheap and I'd rather have 4 of them set for different boxes/situations than eff with trying to set them perfectly for every use.
I like your attitude mike. At work i often "modify" tools for certain jobs. Bent, cut, welded together, ground down. Much better, saves a lot of unnecessary effort when you're contorted around hydraulic pipework in a greasy pit etc!!. And the golden rule is, the hardest nut/bolt/fitting to get to is always tight the whole way haha
Mike Daniel, That is a genius idea! For a production shop that would be my call. Color code the router to the templates. Remove all doubt and question. At least try to. Onya.
We don't actually weld them, just crank the lock down as tight as it will go and don't ever touch it. Also, keep them on the floor because that way they can't fall to floor and whack the adjustment. I posted a pic of my shaping room once and there was a router on the floor, one of the guys on here (I think it was Keith Melville) picked right up on why the router was there.
Our routes are very easy - low density foam and no stringer - but they have to be super-precise. If we have to re-set a router bit it's a 30 minute process involving about 20 test runs.
This is what I came up with as any time you have to level the jig the cut depth changes. I level the jig and then do a test cut in the center, measure and adjust the router as needed.
The jig is so long that there always seems to be a difference between the center fin and the fronts because of rocker. And yes Mike it sure is nice when there is no “twig” down the center of the blank. That could be an interesting thread; the pros and cons of stringers…
The Ryobi trim router isn’t a very quality tool. I was getting cuts that were too deep and was resetting it repeatedly. Finally dawned on me that though it seemed to tighten the retaining nut was stripped. Fixed it with a hose clamp around the whole body of the tool. It’s a pretty crap tool but since it only cuts foam it’ll probably go a good while.
Yeah I had one that stripped the bolt as well. Easy fix with a new bolt and wing nut. The trick to trim routers is to plunge them on their edge. Turn the router on and set one edge on the jig with the router tilted back at an angle. Lean the router forward so that it is upright and plunges the foam in the center of the jig. Proceed to rout hole. This is the method Greg Loehr uses in his film . He uses a Harbor Freight trim router. If you are tearing foam it is either your method or your bit. Always better by the way to make multiple shallow passes when doing the center box(stringer).
