What’s the thinnest I can shape the tail section down to for a longboard, and still have enough thickness to safely install an adjustable center finbox? Aren’t the finboxes approx 1- 1 1/2" tall? Can they be shaped / sanded down if some is sticking up out of the bottom of the routed slot? Also any problems with center stringer mounted plugs and thickness? I’m only shaping, not glassing and finishing. HELLLLLLLLLLP, PLEASE.
What’s the thinnest I can shape the tail section down to for a longboard, > and still have enough thickness to safely install an adjustable center > finbox? Aren’t the finboxes approx 1- 1 1/2" tall? Can they be shaped > / sanded down if some is sticking up out of the bottom of the routed slot? > Also any problems with center stringer mounted plugs and thickness? I’m > only shaping, not glassing and finishing. HELLLLLLLLLLP, PLEASE… A fin box is 1" tall and you do have a little bit you can shave off, but not much. Best thing to do is have the glasser put 2 or 3 extra patches of 6oz glass on the bottom of your board were the box will be. they should be an inch or so wider and a couple inches longer than the fin box. then put a layer or two down in the bottom of the routed out slot before the box is set. Some cheap insurance that can help reinforce the weakened area around the box and plug. good luck, Scott W.
Gman, let me clarify that. You can shave a little off the part of the box that goes into the board and you can grind off whats sticking out after the box is set. How much you can leave out I’m not sure. A good question for a glasser. I hope this helps, Scott.
What’s the thinnest I can shape the tail section down to for a longboard, > and still have enough thickness to safely install an adjustable center > finbox? Aren’t the finboxes approx 1- 1 1/2" tall? Can they be shaped > / sanded down if some is sticking up out of the bottom of the routed slot? > Also any problems with center stringer mounted plugs and thickness? I’m > only shaping, not glassing and finishing. HELLLLLLLLLLP, PLEASE. A box can stick out so much before it loses its foot print and will flip over when force is applied to it. So what I do with a really thin tail is, position where you want the route to be, caliper it front and rear. The front will almosr always have enough meat to allow a full depth route. Figure out the rear depth and go to the max, right up to the glass of the deck. Move forward about one inch and push a pin into the foam, see how deep it goes before hitting the deck glass. Route as close as possible to the deck, move forward again and repeat this process. It will be a staggered route, with the front of the box at regular depth and the rear sticking out the most. It is much better than putting the whole box in shallow. And my advise is to always put some glass between the box and foam, I watch at our glass shop and scratch my head when they put the boxes in with resin only? http://www.JimtheGenius@aol.com
…Is it ok to use chopped glass and resin to set a box? I have seen it done, but always chicken out and wrap the whole thing in cloth. Scott.>>> A box can stick out so much before it loses its foot print and will flip > over when force is applied to it. So what I do with a really thin tail is, > position where you want the route to be, caliper it front and rear. The > front will almosr always have enough meat to allow a full depth route. > Figure out the rear depth and go to the max, right up to the glass of the > deck. Move forward about one inch and push a pin into the foam, see how > deep it goes before hitting the deck glass. Route as close as possible to > the deck, move forward again and repeat this process. It will be a > staggered route, with the front of the box at regular depth and the rear > sticking out the most. It is much better than putting the whole box in > shallow. And my advise is to always put some glass between the box and > foam, I watch at our glass shop and scratch my head when they put the > boxes in with resin only?
…Is it ok to use chopped glass and resin to set a box? I have seen it > done, but always chicken out and wrap the whole thing in cloth. Scott. I prefer to set whole pieces of cloth over the route, I feel it prevents cracking of the resin between the box and foam. http://www.JimtheGenius@aol.com
Also not a bad idea to reinforce over the box installation to prevent leaks at the box to foam seam or even breakage at the front of the box on a single stringer. Copied and pasted from a previous post: 1) I like double stringers - wedge or parallel - doesn’t really matter. Once you’ve routed out the hole the box goes in, you’ve violated the stringer integrity on a single stringer board. Your stringer is about 1 1/2" - 2" thick where the box goes in but after you’ve routed for the box it’s down to practically nothing at the front of the box. I’ve seen numerous leaks, stress cracks and even total breakage right there at the front of the box where the impact of a fin hit was transferred right to the front of the box where the stringer once was. Bruce Jones has come up with a neat method of inserting side stringers on either side of the box extending beyond the front of the box to prevent damage from fin hits. 2) I route after the hot coat. Mask off the bottom around the hole. I line the hole with several pieces of cloth to help reinforce the perimeter of the box and strengthen the resin bond to the foam. I also take a level and make sure the routed area is level so resin doesn’t run out the low end. 3) I cut out the spacer or riser that bridges the slot for the fin. I then take the fin I’ll be using and put it in the box. Mask around the top of the slot and base of the fin so no resin gets inside the box. I put the fin in the box so I can make sure the box is straight. It sucks if you end up with a leaning fin because the box wasn’t straight. 4) Sand the outside of the box with something pretty coarse to get a good bond. 5) Mix up some sanding resin and pour some in the hole with the fiberglass pieces in place. Set the box in there and work it around until the resin oozes out the edges of the slot and the box bottoms out in the hole. Check the fin for vertical placement and tape it down to each rail so it stays there. 6) After the resin cures, peel off the tape and carefully remove the fin. Grind off any excess glass and resin and scuff a big oval area around the box. 7) Mask off around the oval scuffed area and the top of the box. I try to place the tape as close to the edge of the slot as possible. Glass a couple of oval patches over the box with sanding resin. After the resin kicks but before it’s rock hard, take a razor blade and cut away the glass covering the box slot. Again, try and stay as close to the edge of the slot as possible. The more of an overlap over the edge of the box the better. After the resin cures completely,feather out the edges of the oval patch. I block sand the whole area before glossing and live with a slight bump around the box. This “glass-over box” is sometimes offered as a premium on longboards (the Con Ugly being one) but being such a vulnerable area with leaks, cracks and even breakage being so common, I think it’s the way to go. I tried to include as much detail as I could assuming that people who already know how to do boxes have their own way and people reading this are beginners.
What J.P.,S,W.,and T.M. have to offer is the right stuff.Just remember to take your time and think it through.It’s much easier to take a few minutes or even an hour,than it is to rush it,then finding yourself behind the 8 ball! That will DEFINATELY cost you more!Herb.
I like the above idea of cutting from the open face of the box… ding! But glassing around the box to improve the resin-to-foam bond? It seems that you are trading that obstacle for a resin-to-glass bond obstacle. I use a mixture of resin and diatomaceous earth as a filler/glue. The filler structure reaches all the way into the foam. Another trick: I cut my box slots with a hobby tool and a tiny steel router bit. At each end of the box I route out foam on either side of the stringer, an inch forward and back from the box. I taper the slots from the box ends up the stringer, out of sight. I also hollow out notches in the bottom of the hole, on either side of the stringer. I put plenty of filler in the hole. When I insert the box, the filler creates pinchers which grab the stringer in the bottom, and on either end of the fin box. This system probably adds very little pitch strength for paddling over rocks. But it does add bending strength against roll and yaw. For pitch strength, a 1" foam T-band (two stringers) is the stuff… or use the short BJ enforcers sticks.>>> What J.P.,S,W.,and T.M. have to offer is the right stuff.Just remember to > take your time and think it through.It’s much easier to take a few minutes > or even an hour,than it is to rush it,then finding yourself behind the 8 > ball! That will DEFINATELY cost you more!Herb.
Also not a bad idea to reinforce over the box installation to prevent > leaks at the box to foam seam or even breakage at the front of the box on > a single stringer. Copied and pasted from a previous post: 1) I like > double stringers - wedge or parallel - doesn’t really matter. Once you’ve > routed out the hole the box goes in, you’ve violated the stringer > integrity on a single stringer board. Your stringer is about 1 1/2" - > 2" thick where the box goes in but after you’ve routed for the box > it’s down to practically nothing at the front of the box. I’ve seen > numerous leaks, stress cracks and even total breakage right there at the > front of the box where the impact of a fin hit was transferred right to > the front of the box where the stringer once was. Bruce Jones has come up > with a neat method of inserting side stringers on either side of the box > extending beyond the front of the box to prevent damage from fin hits. 2) > I route after the hot coat. Mask off the bottom around the hole. I line > the hole with several pieces of cloth to help reinforce the perimeter of > the box and strengthen the resin bond to the foam. I also take a level and > make sure the routed area is level so resin doesn’t run out the low end. > 3) I cut out the spacer or riser that bridges the slot for the fin. I then > take the fin I’ll be using and put it in the box. Mask around the top of > the slot and base of the fin so no resin gets inside the box. I put the > fin in the box so I can make sure the box is straight. It sucks if you end > up with a leaning fin because the box wasn’t straight. 4) Sand the outside > of the box with something pretty coarse to get a good bond. 5) Mix up some > sanding resin and pour some in the hole with the fiberglass pieces in > place. Set the box in there and work it around until the resin oozes out > the edges of the slot and the box bottoms out in the hole. Check the fin > for vertical placement and tape it down to each rail so it stays there. 6) > After the resin cures, peel off the tape and carefully remove the fin. > Grind off any excess glass and resin and scuff a big oval area around the > box. 7) Mask off around the oval scuffed area and the top of the box. I > try to place the tape as close to the edge of the slot as possible. Glass > a couple of oval patches over the box with sanding resin. After the resin > kicks but before it’s rock hard, take a razor blade and cut away the glass > covering the box slot. Again, try and stay as close to the edge of the > slot as possible. The more of an overlap over the edge of the box the > better. After the resin cures completely,feather out the edges of the oval > patch. I block sand the whole area before glossing and live with a slight > bump around the box.>>> This “glass-over box” is sometimes offered as a premium on > longboards (the Con Ugly being one) but being such a vulnerable area with > leaks, cracks and even breakage being so common, I think it’s the way to > go. I tried to include as much detail as I could assuming that people who > already know how to do boxes have their own way and people reading this > are beginners. John, when I was running my own factory, every fin box was sanded down and reglassed with 2 layers of glass over them. I can’t remember any of them pulling out or breaking from “normal” surfing accidents. After hotcoating, a regular sand job was done with a gloss over the patch. When the rubout was finished, I’d put the fin box route jig back in place with a slip in inner template that held a router with a carbide “V” bit. I’d drop it down just enough to cut out the cloth covering the fin slot and put the slightest champher on the edge of the fin slot. Early on I found if the covering cloth was flush to the slot it would snag and pull up when removing the fin. http://www.JimtheGenius@aol.com
That sounds like a great way to do it! Few manufacturers go the trouble of even covering the box seam at all anymore.