8'-0" board with 1/8" stringer?

Hey guys I’m building a 8-0 mini longboard/Mal, 8’-0" x 23" wide x 2-7/8" thick.  

The blank I’m using is a US Blanks 84SP, blue density with a 1/8" basswood stringer.

Glass schedule will be 6/6 deck, 6 bottom, poly resin, single fin box (would love to use epoxy but I’m allergic). I’m around 215 lbs. This is going to be my longboard for small NJ surf.

Looking at the blank, that 1/8" stringer looks awfully tiny, do I need to be worried about it? It’s kind of bothering me. I’ve never done it but I was thinking of making it triple stringer with Sandeply (cedar if I can find some), I’d rather not have to but I’m worried about my fat ass walking up and down this thing.

I don’t have a definitive answer, but I would be worried too if it were mine, 1/4" seems like the minimum on a board like that. I’ll vote for the triple stringer.

Wouldn’t wonder as much about it if it were “Ply”.  1/8" Bass is a stock stringer for up to 8’.  But you can usually get ply for the same money.  I sell blanks up here in the Northwest and I order Ply in everything less than 8’.  I  spec 2-- 1/8" Bass for Egg blanks and anything over 8’.  If you’re going to ride it in small waves it probably won’t snap.  You can always put a strip of Carbon down the stringer or Vector Net…   

Use S cloth , make sure that you do three full wraps on the rails .

Thanks McDing, ahh ok so it’s the stock stringer. I completley blanked when I picked the thing up, didn’t even think about the stringer, should have orded a wider one. Going for a more “classic” look with a resin tint cut lap, haven’t used carbon or vector net. 

How is the sandeply to work with as far as a stringer, will poly stick to it? Searching the forum I thought I saw your name pop up.

 

Sanderly is easy to work with.  It is “three-ply” and comes in various thicknesses.  The one I buy the most of comes out somewhere between 1/4" and 3/8".  It’s thickness is in mm’s and I don’t remember what that is.  I do fins with it and stringer blanks.  You could do a couple of offsets with it.  I’m not sure about the look though.  How traditional that would look etc.  You can also by Redwood or Cedar “bender board” usually in the Garden/Nusery section of Home Depot.  I don’t remember the width.  But considering that the stringers would be offset at the rails even 4" would be wide enough.   Comes in longer lengths.  I have joined Sanderly on longboard blanks by V cutting a Male/Female joint.  Just don’t put the joint in the nose or tail.  Hope that helps.   Why only 8’ for a longboard?

for more breaking strengh than a 1/4" stringer, keep your 1/8" and lam a strip of ud carbon over like mcDing say. i would go with a strip top and bottom. you can sand a small groove to adjust carbon to avoid sand through. bonus: it ll give the black wide stringer look “à la mode”.

Thanks for the help guys, I’m leaning towards the offset stringers, I’ll see what I can dig up as for as cedar or redwood first. I know I can get the 4’x8’ Sandeply that’s 5.2 mm (.205"). Never cut up a blank before but I think I’m up for it, found some good tips in the archives. 

The carbon thing is interesting, from what I’ve read I thought that you don’t get much benefit using it with poly compared to using it with epoxy. But if it’ll add some decent strength with poly I’ll give it a shot. Is it possible to do a resin tint cut lap with the carbon strip though? 

As for the longboard, I’ve never really had one, I’ve had mostly Mals up to around 8-6 which would catch pretty much anything here on the tiniest of days. I surf mostly wide, thick short boards, eggs, simmons type stuff.

You could do the tint in 4 oz top and bottom .   Then put the Carbon down under a clear 4 oz on the bottom and a 6 oz on the deck.  Free lap the 4 onto the deck, but just rail cut the deck at the Apex.

not a problem to use carbon with polyester resin, élongation to break of polyester is higher than carbon fiber so it’s right for tensil strengh, with epoxy carbon strip will take more load in compression before break.

Another possibility is PVC.  You might be able to purchase a couple of pieces at a larger sign shop.  They buy it in sheets.  Comes in colors like white, red, blue, black etc.  A couple of black stringers offset would look pretty cool.  Even if you cut for stringers at six inches from center and just do a black glue line with Poly or Epoxy resin , the glue lines will add strength to the blank.  PS;  You got more options than you thought you had.

I think I can get some Redwood or Cedar bender board, it might not be tall enough though. I guess I could use Poplar ply too? If I go with the lighter colored wood I could tint the glue black or the color of the lam.  

If I go clear, Lemats idea would be pretty easy I guess with the carbon strips, just not sure what kind. I guess it’s the web backed tape with single or multiple strips of carbon.

I was hoping the consesous would be it’s fine which it might, I just wanted to shape and glass the board, too many options now haha.

I should have just ordered a wider stringer. The first board I ever made was from a Clark 8-3E Green density with 1/4" stringer (might be 3/16"). I beat the hell out of that thing but after many years of abuse and laying in the yard a lot it needed help. I stripped the glass, reshaped (7-0 single fin) and glassed it about 8 years ago and it’s still going strong for a 20 year old board with tons of use.

Yes 1/4" Bass is a good stringer.  Not totally bullet proof, but very durable.  I mostly order 2-- 1/8" Bass glued at center.  All the Blank manufacturers these days refer to more than one stringer glued at center as a T-band, although it is not in the traditional sense.  The two pieces of wood with grain running differently creates a “glue-lam” effect.  Much stronger than a single 1/4".

Ok I got hold of some cedar for these stringers from my neighbor. Really nice stuff, 1/4" x 5" X 8’ pieces he used to build a kayak years ago so they should be nice and dry.

Question is do I need to worry about glassing over these things with poly resin, do I need to seal or prep them in some way? After poking around the web I saw Surfblanks Aus mentioned that their blanks with red cedar stringers needs sealing (lam resin) before glassing.

I’d hate to have issues with the glass sticking after going through the trouble of cutting, gluing up and shaping a blank. Am I crazy lol, there has to be tons of cedar stringered boards with poly out there.

The stringer I use on everything over 8’2(sometimes even 7’8) is two 1/8" Basswood or “Darkwood”, glued at the center.  When you order a blank you are charged additionally for cuts and added wood.  Either thickness or additional stringers.  1/8" Bass is considered the stock stringer in any blank by all manufacturers.  Talking Poly of course.  Stringers laminated together at center are spec 'ed as;  two 1/8" @ center T-band.  This is an incorrect use of the term “T-band” in its 60’s origins.  But any combination of wood at center these days is referred to as a T-band by US Blanks, Millennium, Arctic and Marko EPS.  Don’t get me wrong I also order three stringers offset two stringers set apart and other combinations as well.  But for blanks I resell to other shapers I use a combination of two 1/8 or even 3–1/8" at center. In this combination I pay for the extra wood, but only one “cut”.   First guy I had seen do that combination was Jerry Grantham in Pismo Beach.   I think you are fine with the 1/8" stringer as long as you don’t abuse it in larger surf.  Repeated myself here in an effort to clarify.  Enjoy your new Mal.  Lowel

Thanks for the info again McDing, I appreciate it but I think you replied to an older post in this thread. 

Check out my post from today at the bottom of the page regarding cedar stringers. I’d like to give it go if there are no issues with glassing with poly or how to prep before lamming.

Aloha JohnnyK3,

To give you some perspective, between 1969 and 1972, I surfed plenty of 12 to 15 foot waves on the North Shore,  on a 7’ 10’’ board with a 1/8th inch stringer with 2x6oz deck and 1x6oz  bottom.      Never had any structural problems, related to the stringer.       I was using both Spruce, and Redwood.        You’ll do fine with WRC.

So, a question to those with more experience:  what about simply adding a layer of 4-oz to the bottom and making sure all layers wrap the rails, or even making it 4/4 on the bottom and 6/6 top?

You would be gaining an added 2 oz top and 2oz bottom.  The difference isn’t in the extra weight per yard but rather the fact that you are wrapping those extra layers at the rail.

every thing that increase skin stiffness increase board durability against dent and buckling. Board snap because of too much flexural bend, skin wich take compression+flexural load buckle lift over foam and break. stiffer blank,  ie denser foam or stiffer stringer reduce flex = need more force to break. stiffer skin reduce flex too, reduce buckling and increase dent resistance = need more force to break and to dent.  Windsurfer put all strengh in skin and use extra low density foam with higher volume board it seems to be the best built for strengh to break / weight ratio. Pound for pound a sandwich build wind surfboard take far more load than a traditional surfboard build, mostly because of higher stiffness, by design (thicker board) by build (stiffer skin).

So for a surfboard you can reduce stringer stiffness contribution and increase skin strengh with more layers and have a “stronger” board with a different feel. That’s what is do with eps/epoxy board when they are made with a lighter blank (around 1.5 lb) flexible stringer ( Pu or pvc foam, or thin light wood or carbon strips) and more glass skins : for same weight than stock Pu/pe those board have more dent/ding durability, more break strengh for those who feel (are) stiffer. They also look “different”, are more heat sensitive, take water when dinged, are more expensive…