How do you go about fixing a broken nose. Its on a shortboard and it is totall y snapped off. I have it still and jsut wondering hwo to tack it on so i can galss it.
You need to strip the glass, whichever side is worse, from either the deck or the hull, back at least 16" from the break.
Cut the foam away so the broken nose looks like a ‘V’. Cut 1/4" width of foam away from one side of your stringer, as far back as you removed glass.
Get a ‘donor’ nose. Hang out at surfshops that do ding repair or ask around to find someone with a broken board. A longboard or ‘funshape’ is best, because there will be enough foam to shape back down to your board’s shape. You won’t be needing your old nose piece.
Cut the donor nose into a diamond shape so it fits in the V you made in your board. Don’t worry about how big it is - you want it bigger than your board so you can shape it down once its glued in.
Cut the donor nose off its stringer, on the same side of the stringer as you cut away foam from your board. Get some 1/4" marine-glued plywood, some basswood, even some redwood - anything that’s light & strong and 1/4" thick. You’re going to laminate in another stringer like a splint next to the old one in both the board and the nose piece as you glue on the donor diamond-shaped piece into the V you made in your board. There are lots of kinds of glue you can use - inlcuding catalyzed resin - but whatever you use, test it first on some excess pieces of foam from both your board & the new nose. You want to make sure it won’t eat the foam.
Once the new nose is glued in with the new stringer splinting the break, you can shape the new part to match the old nose. Then glass like a new board & you’re done.
One of my favorite boards is a complete Frankenstein - a '71 Midget Farrely 7’10" with a UFO-type tail and the 16" nose of a Town & Country, complete with partial yin-yang lam. Looks like an abomination, but surfs like crazy…
Good luck
How far down? if it’s within about 6" from the tip, you should be able to insert a small wood dowel or chopstick section next to the stringer, poking it into the foam on either side, for a snug fit. Take the dowel out, fill holes with resin, put dowel in one side, coat mating surfaces with microbubble mayo, push together, position carefully with tape, sand smooth the extra mayo that oozes out, glass, done.
If it’s further down, it’s more like a broken board, and positioning is more crucial. I usually glue a plywood splint next to the stringer on one side, let it harden, then mate the two sections on a table, with blocks or books or whatever holding the rocker curve and preventing any twist, just line it up dry, then don’t move your blocks… if it’s a more irregular break, I’ll stick it together with resin, then fill with the mayo as a separate step.
Prep of course should be to wash and dry to eliminate salt, knock off any broken or loose bits, including delammed glass, shattered stringer, loose foam, etc, sand all exposed surfaces, blow/wipe clean…
wells
awright, having read the other responses… and having done more than a few busted off shortboard noses… and busted boards…
This is a clean break, right? With not a lot of glass torn loose, no? Lets not go nuts here. The first thing you do is set up a jig like wells mentions. Don’t worry about a precise fit foam to foam, 'cos some of the foam got squashed when it broke, in all likelihood. Go for getting the curves right. Set your jig up and…
Make a batch of cabosil, a thick one, about like expensive peanut butter. Catalyse lightly. Butter both sides of the break and stick it together in the jig fairly tight but make sure the curve and alignment is smack on, gently scrape off the excess cabosil that oozes out ( which will save you mucho sanding later and a very good chance of sanding through into the foam, lots of filling and sanding all over again) and wait for it to go off. Sand a little ( you’ll need to do some - life isn’t fair) and it’s ready to glass.
Do not strip back a bunch of glass unless it’s torn loose already. It’s holding just fine to the foam as is, why screw with it.
Do not futz around with dowels or chopsticks or popsicle sticks, they add exactly and precisely zero ( 0, nada, zip, none what so bleeping ever ) percent strength to the repair while at the same time adding a two thousand percent (2000%) chance of buggering up the alignment of the two pieces. We are talking about something stuck into the foam, by eye. Guaranteed, it won’t be the right angle. Guaranteed, a teensy weensy stick stuck in foam will hold exactly jack squat. I have cut apart and redone more than a few of those where there were twists and bends and really weird angles where somebody thought a stringer reinforcement was real necessary 'cos of the common ‘wisdom’. It’s not. Otherwise, we’d just paint the blanks with resin without all this tedious fiberglass cloth nonsense and they’d work just fine, ok? But we don’t, we use fiberglass cloth, which is the real strength in a board. Okay? Good.
Don’t waste your time splinting the stringer either. Again, it adds zero percent strength while adding a lot of weight Plus a whole lot of work. To accomplish zero extra strength. If the stringer was all that damned strong, the board wouldn’t have broken. But, it did. Don’t worry about the stringer.
Instead of either one of those ( again, assuming a clean snap) , use a narrow band of, say, 6 oz cloth completely around the board bridging the break and then a wider one. On a short board, within a foot to 18" or so of the nose, the first band can be around 4" wide, the second maybe 8" wide. Close to the middle of the board, make it at least twice that wide. Sand where the cloth will go wiith maybe 80- or 100 grit to give it something to stick to, clean the dust off with acetone. Use laminating resin, squeegee well. I like to have the lower band of cloth start in the center of the bottom and lap around back to the center of the bottom, next band goes from center deck to center deck. Feather the edges with coarse paper done lightly, hotcoat, sand and gloss and you’re done. The board might break again, but not there. The two bands of cloth, one narrower than the other, allow the board to have something resembling it’s original flex.
If it wasn’t a clean snap? With some cloth torn loose? Okay, very carefully cut away the loose cloth. Try not to score the foam with your blade too much- I like a utility knife for that. Do a patch with 6 oz cloth like you’d do an inlay, just in the naked foam area ( presumably the old cloth was 4 oz, and took a skosh of foam with it, the 6 will make up for that ) , but do it after you have stuck the two pieces together. Then, lay some 4 oz over it and lap it onto the ( lightly sanded ) old cloth by a couple inches, and of course that’s after lightly sanding through that lapped area like I described above. This will be plenty good enough to tie it together without some ugly concaves in odd shapes that’ll need filler and other miserable work. Then, do the cloth band things as above, hot coat, sand and gloss all the new cloth .
leastwise, that’s the way I do it. Seems ( several years into it ) to work just fine, no complaints from the customers.
doc.
Doc - fair enough. I mostly only repair my own & a few friends’ boards, so I do tend towards the overkill 
I also surf primarily longboards - at 220 lb, my shorty is 7’2" - so repair weight isn’t usually prime concern.
I do understand, though, that a surfboard is basically an I-beam. The glass (yes, of course with cloth) is the two flat panels, giving side-to-side strength and compression resistance, and the stringer is the web, providing the vertical shear strength. Otherwise, we’d still be seeing the stringerless chips of the 70’s… The whole ‘donor nose’ and V-cut deal is probably overkill for the average busted tip, but if its your own board, you have the time, you can use the knowledge, and you want it to last, its the way to go…
Actually, no, a surfboard is more like a box girder or other monocoque structure . When the skin fails, the structure fails.
While the I-beam model sounds good initially, the relatively pathetic bond between wood and glass/resin kinda blows that one away, let alone the relative strengths of the wood and the glass/resin. To get a true I-beam you’d need a well secured glass/resin encapsulation of the wooden stringer that was also well bonded to the skin. What a stringer will do is modify the initial stiffness of a board and provide a nifty centerline. But that’s about all. I have seen more than one busted board where the break was triggered by the splintering stringer that failed and then triggered glass-foam bond failure. And a few where the stringer failed and the board was okay, both older boards with rotted balsa stringers that surfed just fine and other, newer boards with cracked stringers that survived just fine.
The ‘chips’ you’re describing, like the Farrelly Stringerless, owed their structural problems as much to their thin and sharp-edged cross section as anything else, not too great with a monocoque structure. A deeper cross section with less ‘knife-like’ rails would have worked better structurally. When they broke, it wasn’t ( in the case of the Farrely Stringerless V-bottoms) at the relatively thick Vee area but up forward where leverage combined with cross section to make a very weak point. Plus they had lighter glassing and foam than their immediate predecessors. The idea of the stringerless boards, though, was to incorporate some flex. Such are the tradeoffs.
In roughly the same era I got to see one of Nat Young’s factory ultra-lightweight, light glassed, no hotcoat no gloss ( though it had a balsa stringer) Webers which wound up breaking in waves that didn’t bother the heavier glassed, heavier foam standard Webers of the same shape. Several times, as it was put back together more than once and then broke in different places where the glass hadn’t been reinforced. And then there are the numerous surviving boards with colored foam stringers…which have no more ‘structural’ stringer to them than a stringerless board or one with a glue-line ‘stringer’.
However, don’t tell this to the main surfboard buying public, heretical as it is. They have been told that a stringer makes a board stronger. Me, I tend to believe what I have seen.
doc…
As a young child, Doc was cornered by a pack of wild stringers and stringer splints, which frightened him terribly. He has been a bit touchy about them ever since, and can hardly be in a room with a chopstick or tongue depressor to this day.
Doc’s absolutely right about the I-beam. From an engineering perspective, the purpose of an I-beam cross-section is to simply keep the flange members (horizontal sections) apart at the same distance and perpendicular to the vertical section under loading. The I-beam is just an economical (lighter) version of a solid beam. It is no stiffer than a solid section of the same size. The exception is for very long solid beams, which will bend under their own weight; so in that sense an I-beam is stiffer as it is lighter and can span longer lengths. But that doesn’t apply to surfboards. Review the concept of a stringer functioning as an I-beam: The glass forms the flanges of the beam and the thin stringer is the vertical section. The foam keeps the flanges parallel since the wood is too thin to support it. Therefore the wood really doesn’t do anything in the sense of an I-beam since it can’t support the flanges on it’s own. It’s just a referenced center of the beam as Doc pointed out. So what does the stringer really do? I gives a certain degree of flexibility (spring memory really) to return the board to its original shape after loading (primarily twisting). This is what is meant in talking about the “stiffness” of stringers; more in the sense of a stiff spring than a loaded beam. It does not influence ultimate breaking strength. Breaking a board causes the glass to compress on one side and go into tension on the other side. Resistance to these forces is entirely a function of how well the glass is bonded to the foam, and to a lesser degree the thickness of the glass.
So what does all of this engineering BS have to do with fixing a broken board? Just make sure you can get the glass used for the repair bonded well to the foam and original glass. The old glass you laminate to must also have a good bond to the foam; if there was peeling when it broke make sure that you know where the bond is still good. The strength of the foam-to-foam bond when you put it back together means nothing. All this needs to do is hold it while you’re glassing; the glass will structurally tie the foam parts together. Putting splints, pencils, dowels, tubes, etc. in the joint will not increase the breaking strength. If it does break again these items will tear up the foam and glass and you’ll just have more to fix.
I have a buckle that runs to both sides of the stringer on an old board, but the glass is still stuck to the stringer. when I flex it, the glass comes up on the deck to either side, but stays down over the stringer. Is it possible that the glass-wood bond, being stronger than the glass-foam bond (because wood is stronger than foam), helps keep the glass attached to the deck longer and prevents catastrophic failure? I know boards fail first by the glass on the compression side buckling up, or delamming, maybe the wood holds the glass down withstanding forces that would rip up the foam…
That would explain the results put forth in “Essential Surfing” (george Orbelian) where they tried different stringer configs, the winner was a stringer that had been cut along either side and glass tape inserted along the stringer, lapping flat onto the deck. This would greatly enhance the deck glass’s bond with the stringer, making it harder for it to buckle up and begin failure.
Wells
Actually, no.
Doc has been fixing boards for over thirty years along with looking carefully at structural failures in those boards and what caused them ,plus studying mechanical engineering, materials science, marine engineering and naval architecture. Not buying into the BS peddled by the surfboard industry, though.
Pete is smack on with his analysis, as usual. In fact, Pete, an odd thought came to me as I wrote this - we all have seen or dealt with vaccum bagging laminates, but what about ( if I may coin a term) hyperbaric laminates: laminating under pressure to get better resin penetration into foam? I dunno that it might not make a better bond, foam-glass. Problems with it- yeah, the non-uniform density of typical urethane surfboard blanks might cause distortion and depressions in the surfaces, though this would be less likely in more uniform density foams like the styrene foam blanks cut from extruded billets.
Or, would vaccum bagged laminates with their effectively 1/2 ATM pressure all over accomplish the same thing without the crushed/compressed foam worries?
Leastwise, those are my initial thoughts, be interested to hear what you think.
doc…
Doc wrote:
"Actually, no.
Doc has been fixing boards for over thirty years along with looking carefully at structural failures in those boards and what caused them ,plus studying mechanical engineering, materials science, marine engineering and naval architecture. Not buying into the BS peddled by the surfboard industry, though. "
Thanks for answering my question. Though your answer was brief, the overwhelming weight of your qualifications leads me to take your word as fact, and is nearly as informative as a good explanation. Good luck with that thing with the surf industry, sounds like you really have it in for each other. As I have been making my own boards in my backyard recently, I have been participating as a consumer less and less. Also, the last two boards I made had no stringers, but one had rail channels. What does one of those look like under failure usually, dare I ask?
Happy surfing,
Wells
Using deeper resin penetration into foam something I’ve been looking at recently. Obviously, there’s a weight penalty. The easiest way would be to squeegee a cheater coat on the blank first. Overshaping the blank to expose the lower density foam is another way. I did just that in June, and the lamination went on much tighter. Laminating in a vacuum or over-pressure will have big effects on the viscosity of the resin while you’re doing it. These effects may negate the benefits. The problem with the glass/foam bond is really an interface issue of a soft, flexible material and a hard one interlinking. These problems are usually addressed by another layer of a “buffer” material. 3M double-sided foam tape is a good example of this idea.
Interesting, Pete, I hadn’t thought of/about viscocity effects.
'Course, going down this line of thought with a buffer layer some distance further leads you to the light foam core/denser foam skin layer over it construction that Bert has been using, among others. Even then, though, if I’m following the same track as you are, you have the same soft, flexible material/hard material interlinking problem but varying in degree. The divinycell people may have anticipated this somewhat with their divinymat material ( see http://www.itchingforfun.com/Product_Catalog/Core_Materials/core_materials.html ) along with considerable other tech info …
drat, I was gonna relax this week too… oh well, keeps the ol’ brain from stiffening up too much as it gets older.
Looking to fix a broke nose 8 inches from the tip on shortboard. A couple questions for experts. The glass is still intact on deck and seems to provide help in lining up of both ends. Should i leave this intact or cut it completly apart? Also what is the jig you are speaking of and finally what is CABOSIL? Thanks
(1) Trim back the glass from the break because it is usually delaminated anyway. (2) For longboards, the jig I use is simply a pair of 2x4’s with some 1x4’s screwed under them to form sort of a train track. You set the board on the “rails” of the track and use a long bar clamp to hold the pieces while bonding. The clamp uses two grooved and vee’d wood pieces to engage the nose and tail. The clamp is tightened and shimmed at certain places until the rocker is right. This doesn’t work well with shortboards because there’s too much nose rocker for clamping. For these I use Gorilla glue, waxpaper, and alot of 3" wide tape. Apply the glue to one side of the break and spray a light coat of water on the other. Wrap the break with wax paper and tape. Run a piece of tape from the bottom over the tip of the nose to the deck. Adjust the tension on the tape until the rocker is right. Leave it overnight,remove tape, and glass per Doc’s instructions. (3) Cabosil is a thickener for resin. You can also use Sil-cell or Q-cell.