rout[er]ing out a finbox ??

does anyone here have photos of the process , please , and / or a clear description of how to do it ?

I ask , because I have a board I want to do this to, in order to be able to shorten the board , and thin the tail .

cheers in advance for your help !

ben

…indoors , keeping warm…

it’s a 10" ( 25cms) finbox …



Ben, your router should be equipped with this (“collar guide”? How would you call that?)

…and you should make a template, so that the guide follows the template, like this:

Then, all you have to do is position your template where it should be, make it stay there with tape or clamps or whatever, then go for it.


great stuff , thanks heaps for that , Bill !

and I’m assuming …the router / template “gap” has to be wide enough , so I am not hitting the plastic of the finbox , but rather , I am instead able to be taking out the milled fibre border around the “outside” [?perimeter?] of the box , oui ?

cheers ,

ben

No, no, go for the box itself: shallow passes, wear goggles, a carbide bit would be better.

…does it not melt the plastic ?

As I said, shallow passes, go slowly, get a feel for it and see what speed works best (if your router has a variable speed setup, of course…)

Hi Ben -

I have a slightly different router jig with a frame that keeps the base of the router where it needs to be. The slot in the jig is wider than Balsa’s. All the slot does is allow an opening for the bit… the frame does all the work of directing the actual cutting pattern. With such a jig and a narrow diameter bit you might be able to cut around the box to remove the resin/fiber.

You will still have to pop out the box which will be glassed to the blank and stringer on the underside. Beware of stringer and foam damage when you grab the edges of the box with vice grips and start tugging.

If saving the box isn’t a priority you could route out the box itself - just make sure to remove the screw plate.

If it helps you out, when i just planed out a few boxes from my windsurfer, the plastic didn’t really melt, and i was pushing down hard on it, with old, blunt blades, cut pretty good really.

Yes, John, sorry, I didn’t even think of the possibility that Ben might actually be willing to re-use the fin box for another board…

In which case, cutting around, of course, is the way to go. And, as I told Ben in a PM, (and you pointed out, too) be careful not to tear too much foam and stringer material…

Quote:

Hi Ben -

I have a slightly different router jig with a frame that keeps the base of the router where it needs to be. The slot in the jig is wider than Balsa’s. All the slot does is allow an opening for the bit… the frame does all the work of directing the actual cutting pattern. With such a jig and a narrow diameter bit you might be able to cut around the box to remove the resin/fiber.

You will still have to pop out the box which will be glassed to the blank and stringer on the underside. Beware of stringer and foam damage when you grab the edges of the box with vice grips and start tugging.

If saving the box isn’t a priority you could route out the box itself - just make sure to remove the screw plate.

thanks for that , John …

is vice grips / pliers the only way to get the box out , then ?

Because I want the tail thinner [and more rockered ] than it is [for fcs back fin , too] , I will rout out the box .

Balsa bill mentioned in a pm that there is basically not much left of the box if I router it .

Does the router leave a level bottom where the box was , without going through to the deck foam and glass , I wonder ? [I’m new to this …I wish I had been there when a mate tok one out for me YEARS ago …I would have photographed / video’d it , so I would have had a clearer idea …

The plan is to strip , thin , narrow, and hopefully re-rocker a bit more , 

my 7’ single fin , into a 6’4 - 6’6" three finner …

With the cold weather today , and my now holey wetsuit , I have been indoors today , with cardboard , scissors , and camera …uh oh …it begins again ?? [maybe not just yet …$$$$$$$$$ lacking , at present …]

… thanks heaps for the advice , balsa , john , and beerfan !

If you think of anything else to add , please do so !

cheers

ben

G’day Ben

when I remove fin boxes I use the 6mm router bit with the collar ,as balsa mentioned, you have to be patient and let the bit do the work and not push too hard as you’d be surprised how easily your template can start to move under the weight of pushing.

If you use shallower cuts its much easier but much slower and you can save the stringer on the deck. or only cut out the amount of finbox you need to to allow for the new rocker curve, the resin for the plugs will stick to the base of the box no problem.

This way you will also keep the stiffness in the tail of the board when you are reshaping, taking all that thickness of the box out of the centre of the board could prove very difficult to shape.

Depending on how much you wanted to take out of the tail you could also leave the box in and reglass around it then sand it down and use and FCS longboard box adaptor they are about $20 I think.

Hope this help.

Daren

Chip, you can router through the box no problem, I would be VERY careful around any pieces of metal in the box, and make small cuts in depth, and it will be very clean when you are done.

However, to save yourself from flying bits of plastic for 30 minutes, take an Xacto knife or box cutter, and cut through the glass and foam to a depth of 1 inch on all sides of the box.

Then, grab a BFS (big f****** screwdriver). Put the tip inside the finbox pointing at the nose or tail. Whack a few times with a hammer to break the box free from the stringer. Then whack it a few times in the other direction. Short, hard, whacks.

Then grab the box, say a brief prayer to Huey, and pull the box right out of the board. If the foam/stringer appear to be breaking on the deck side stop and go back to whacking it.

Usually this cleanly removes the finbox in about 3 minutes.

wow , thanks Dave !

in the absence of a router , that sounds like a plan !!

since I will be replacing the box with foam , then drilling it out for four fcs plugs [single fin / back fin option too… sounds like I might give THAT a try , first …

…now … WHERE did that “BFS” go ???

cheers

ben

…I do like Blakestah, also with leash plugs…

Howzit chip, actually there are a few ways to get the box out. If you havea dremal tool you can zip the perimeter of the box then run it down the center til you hit foam and just hit the sides of the box and pop out one side at a time .You can also use a drill and drill holes down the center and then hit the sides with a chisel. Aloha,Kokua