Let me get this straight, I route out for the fin boxes after the hot coat? thanks JR
JR That depends on which type of fin box system you are installing. Be specific about the brand(s) you are using and whether it is a large single fin center box, a 2+1 setup or a thruster set. Then you will probably get a range of answers of what works best for everybody here. For me: O’Fishl- large single center and small thrusters- install after shaping/before glassing FCS- after hotcoat/before sanding Fins Unlimited- most after hotcoating and before sanding. Sometimes you will see them installed before the glassing. (FU side fin boxes etc.) * I think everyone will agree that if you install a box under the glass it is structurally superior, just more work and care to get it right. TS>>> Let me get this straight, I route out for the fin boxes after the hot > coat? thanks JR
JR- If you follow the link given to you by Anthony down below there are some decent instructions found on the Fiberglass Supply site. The followup notes indicate that the boxes are routed in the foam prior to glassing and that there are extra glass patched to be laminated on both the top and bottom of the board adjacent to the box installations. Take note on the process of routing these boxes in, it looks like you are going to have have the special jigs and router bits to get the job done right. Pretty costly for an occasional board. TS
Hey JR… I’ve done quite a few long single boxes and I’ve come up with a labor intensive method that works for me: 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.