Having a problem with fin boxes developing leaks and in two cases even breaking loose. Is there a better way to install them? This seems to be a common problem on long boards. I am going to make a new board soon and want to avoid this problem. I have time take extra steps if it will be better. I am talking about long boxes but have had the same happen on FCS.
Check the archives. There’s plenty there. Make sure you cap the box when you done.
The most common mistake is setting the resin off too hot.I shrinks up causing voids.Like the boys said there is a lot in the archives on this subject.
your not using sanding resin are you?
I am not installing them yet. One was on a Robert August Two others were local made boards. I guess I will check the archives. thanks
Hey Lam resin, slow batch, one layer of 6oz shoved in by the box, capped with two layers, woodies spidering out…two off each side, DO NOT SHAVE DEPTH of box.
wipe the box with acetone until it loses its gloss. light sand it. install as recommended above.
LeeD I understood the 6 oz tucked in part but I was lost after that. could you explain in more detail? I was thinking of running a piece of 6 oz under the box then lap it over the edge for a couple of inches around the box then blend it in on the hot coat. thank you for your expert advice.
Hi The 6oz shoved it by the finbox is to insure a strong, crack free bonding agent. Hopefully, you rout so only 1/16th more than finbox all around. The cap is two layers of either 4 or 6, usually pieces of cloth 6"x14", layed on over the finbox, right on the hotcoat. It gets sanded down close to flush before glossing. The woodies are little 1"x6" pieces of hardwood inset into the blank to act as extra stringers to support the finbox. Some people lay it along the length of the box, so that means two pieces of 1"x14", and two pieces of 1"x3", to support the ends of the box. I like little 1"x4" spiders, radiating from the center 4" of the box, like spider feet. The ends of the box is plenty strong, but flex at the middle causes the box to separate from the resin, thus causing leaks. Look at the finbox’s of old poly glass windsurf boards.
Nut cake lunatic wrong way: I ,sorry production team,yep rout it deep to take two maybe three layers under and arround the sides sand the box to break down mold release residue, acetone the box thenwith a razor blade kerf (cool word) like scratch deep the outside surface bottom and sides not hot to get it straight and plumb…sand off yea yea yea excess then comes my madness cut foam scrap and fill slot shy of surface then fikk-sealwith surf wax…sticky soft kid stuff works good…now before you start with this surface contaminating wax …tape off arround the box… that wax will resist the next glass and resin and undo the wonderful intent of the method…ok wax backfill and finger shape that wax down low enough to be like a depression like resivor take off tape and sand the surface to remove wax residue arround edge of boxand make dust to cover sticky surface of wax with fine layer of dust is coolungatta do it…now the glass plan …big layer first even wrap the rail for bullit proofing and glass tailblock build up…additional layers making pyramid that will feather out Rightously,aside if this is a new board this glass can be set inside overlap eliminating sand through common to returning shape to contour overlap can get thick if yo insist in overlapping each of three layers from the deck…Ha Ha HA durability Madman lives hear him chuckle as the epoxy revolution goes down the rincon rock gauntlet chunk klunk …OH MY LEASH BROKE ON THAT LAST FABULOSE FLOATER…such is the life and fixation of the mad genius that dwells on a deep hatred of ding repair…and socially acceptable encumberments…ambrose… on your behalf sharing the depth of my personal insanity dont tell anyone you actually do this they will just shake their heads and prepare your ride to the Home
sorry I did not preview and edit prev post I hope its readable… ambrose…west winds the family is coming back for another go out
I got carried off and forgot the: cut out the glass covering the hole then hot coat and sand leaving a nice rolled over edge …dont leave any glass sticking out over the fin slot orafice asthe slot for roll pin as it will allow pull up when removing fin … leave wax in hole till after the gloss these reinforcement fibers being sealed insure integrity as fibers can wick water into the matrix and degrade the durability of the box…the box clean out is well facilitted with the dremel small size drum sander… this being deliniated my mission here is complete …ambrose…HI HO SILVER AND AWAY!!!..who was that masked man on the white broom? and why was he wearing rubber slippers
50 grit rough sanding the exterior before installation always helps. The resin doesn’t really sitck to the box, roughing up the surface provides a better bond to the “cast” that the resin forms around the box. Boxes should not be made stiffer than the surfboard, otherwise it is pretty hopeless - repetitive flexing of materials dissimilar in stiffness will cause failure. capping is real important, too, the strength comes from the sheet of glass on the board, and getting the connection between the box and the top sheets of glass is your best bet. http://www.blakestah.com/fins/