Stringer Tolerances

General Discussion
1

Hey – first post, first board. I was hoping to avoid posting completely, but I’m at a point where I’d rather ask and get slapped around a bit than go back to learning the hard way. So, on to my question… 

I’ve looked around here a bit, and while I’ve found information on how to trim down the stringer (spoke shave, sharpened-beyond-belief block plane, block plane with angled blade, block plane with custom-cut convex blade, packing tape on both sides to help save the foam from damage, finish sanding to help the block plane slide, etc), I can’t seem to find anything about tolerances. Mainly what I’m looking for is, if the stringer is 1/16th or 1/8th of an inch above the foam, do I still run the risk of the board delaminating, or will the fiberglass and epoxy combo make this difference a non-issue?

Ideally I’d be able to plane the stringer down to perfection with a block plane and call it a day, but I’ve tried this and had to completely reset using an electric planer to remove all the chunks and crappy spots that resulted from my attempt. I’ve got the board back the way I want it as of this afternoon but the stringer is, yet again, just a bit too high. I know my first board(s) will be imperfect in a lot of different ways, but I’m not sure if I can afford for this to be one of them. 

Help? 

 

Update:

With all the help and advice that was given in this thread I thought I’d follow up with some details on what I ended up doing. 

First, I ordered a Wilkro razor plane. 

Next, because I’m impatient (it wont be delievered until a few days from now), and because I found what I felt was a workable sharpening solution for me, I put together some sandpaper and honing compound so that I could sharpen my Home Depot block plane. 

In case anyone wants more details, the two black pieces of sandpaper are 400 and 800 grit, the greys are 1500 and 2000. The green mush is the honing compound, and of course I had to get a honing guide to help with precision a bit. I used some 3m spray adhesive that I had lying around and a piece of plywood to clamp the sandpaper to marble tile so it would be as flat as possible. It’s not perfect, but it seemed to work ok for this. 

I took the blade out of the plane, sharpened it (per some youtube videos and an instructables article), and then tested it out… 

The results were better than I expected! With very little pressure, very little exposed blade, and a good angle, I was able to get the plane to cruise fairly gently over the foam, cut curly-q’s out of the stringer, and not cut big chunks or divots out of anything. Success! 

My technique still isn’t perfect, and as you can see the foam around the stringer is still a bit on the rough side, but this is leaps and bounds better than what I was able to pull off before! Not to mention I now understand that it is possible to get the stringer lower than the surface of the foam.

SO… big thanks to everyone who commented on this thread and got me pointed in the right direction! I think I may still grab a spoke shave for the nose, and possibly a higher-quality block or japanese plane, but for this first board I think I’m good to go. 

 

2

0 to - 1/16th.

Get a sharper tool

3

Get one of those tiny little hand planes, and a small spoke shave (for the area on top where the nose rocker turns up), from a shaping supply store, they’re pretty inexpensive.  A little practise, and you’ll be planing curly-Q’s to get your stringer down to a hair’s thickness below the foam.  Its fun!

4

A bit of foam tear-out next to the stringer is more commom than you think in a hand shaped board.  Keep your tools sharp and take light cuts.  Try to keep the stringer as flush as you can.  Look through the racks in your favorite shop and you will see what I mean.

5

Ok, it sounds like what I need most is practice (surprise!). I have a brand new block plane (albeit from Home Depot and not a shaper supply store), and I did manage to get a few epic full-board curly-Q runs, but most of the time I was digging the plane in too deep and bringing it to a dead stop, causing gouges in both the stringer and the foam. I may be within the 0-1/16th range, but I’m not sure. It’s so small it’s hard to measure, but I can feel the difference, so it concerns me. I’ll go grab a spoke shave for the nose curvature and take a look at boards in the shop to see if I can spot the tear-out, if only to make myself feel better! 

Thanks for the replies! I think on my next blank I’ll focus a lot more on practicing this stringer technique before I do any serious shaping so I can get as much practice in as possible. And I think Huck is right, it sounds like it could be a really satisfying skill to master; those curly-Qs were amazing when they actually happened! 

6

Aloha Brick,

Where are you located?     The block planes that I’ve seen @ Home Depot, need to be ‘‘tuned up’’ for surfboard shaping.      I’ll show you how, or do it for you, if you’re close enough to the San Diego area.       Quality tools, will help you be the best you can be.

7

I own lots of “micro spoke shaves”

And small sharp small block planes.

Lately this one

as Huck shows,

On line @ FGH.

Sharpen it first

nasty sharp.

Adjust 2 just enought

no over do

nats ass, yeah

And I find it better to pull @ 45 degree.

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8

…whisker the stringer down to a frag below the foam level… then fine sand the foam down to the same level as the stringer …presto-no tear-out !

9

This little vintage planer blows everything else I’ve tried out of the water for taking down stringers…especially the cheap mini planes and mini spoke shaves the surf blank suppliers sell.  It takes cheap disposable razor blades and the plane itself can be configured several different ways so you can use it like a spokeshave or like a traditional plane.

 

10
Thrailkill, sadly I'm about 45 minutes south of Ventura (an hour or so north of LA). I'm blown away by the generosity of your offer though! Thank you!
 
kayu, how do you get the stringer below the foam? It seems to me that, unless you have a blade with a very narrow width, you're stuck taking the foam down with the stringer. I'm guessing that's why you angle the plane, but I haven't been able to prove this in practice.
 
mako, the idea of a replaceable/disposable blade sounds great. Are you selling those? A quick google search just tells me that the TSA looks down on disposable razors in carry-on luggage. Go figure! (**EDIT: On second search: http://www.ebay.com/itm/like/131505232451?lpid=82&chn=ps**)
 
So far what I've gathered is that "nasty sharp" (as mattwho put it) is probably the way to go. I found a five page article on sharpening blades on here that I think I'll go over (I can only find parts 2 and 5) ... and then maybe pick up a better plane with some micro adjustment. It sounds like if I were skilled enough (like thrailkill) I'd be able to get away with a cheap Home Depot plane, but I'm simply not, and that's fine.
 
You guys have been amazing. Thanks for all the input!
 
 
11

if you are tearing out chunks, then your plane is set too deep 

if you cannot cut at all until you set the plane deep enough to tear out chunks, then you need a sharper blade. if you cant sharpen your blade, then get a plane with disposable razor blades like shown above

hold the plane at an angle to the stringer to help the blade grab on shallow cuts

 

12

You must know a good woodworker, dad, granddad, neighbour, whatever. Those old codgers will get that cheapo plane sharp and cutting fine.

Secondary bevel and a small hammer and it’ll do the job.

13

I’ve always used the Stanley “Mini Plane”. Spoke shaves of the type that are sold at supply shops are dull as $#|t.  Shape your blank.  Sand and screen.  Then make a pass down the string both sides.  Steady but lite pressure.  Afterwards make a pass down the stringer with screen and a hard block.  Other than signing the blank; planing and screening the stringer is the last step in the shaping process.

14

Brick,

At the risk of stating the obvious, you are pushing the plane angled at 45-75 degrees to your stringer, right? (see the third picture in post #3). Apart from limiting digging in, its also how you make the blade narrow enough to see wood only.

15

some stringers REFUSE to be cleanly planed, the grain does a switch back every few inches, but a arced blade run on the skew on the very minimal of a cut usually gets them presentable. I have  Miller Falls bench plane with reverseible blades, it is one of the very few that I use that does not  have an arced grind on the blade. I grind them myself, have diamond hones to dress them with, nothing worse than the corner of a straight blade catching foam for 9 feet

16

…I stand corrected Brick… it’s a tricky process …but , sheer-cutting or skewing with a small plane will minimize the problem quite a bit…I like Jim Phillip’s method of grinding a blade specifically for the job… that’s gold… I rarely do conventional foam boards these days , preferring to leave it to shapers with a skill level way above my own.

17

This is one of 2 Stanley #53 spoke shaves I have, 5 bucks each at swap meets, antique tool sites have them valued at 185.00$ each.

The stringer pic is a pro glue up by a foam co., small knot that tore loose and wedged into the throat of my block plane and cut a furrow about 6 " long before I came to a stop.

If you are laboring during stringer trimming, the plane is NOT sharp enough and or too deep a setting

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18

red_boards, at the risk of sounding stupid, I’m actually not doing that 100% of the time. For some reason I assumed that angling the plane would shorten its effective length, making it easier to get into the curve at the nose. I never really took the time to envision the blade itself, which makes it obvious that angling it also shortens the effective blade width. Damn. I’m embarrassed to admit it, but that’s a little bit of a revelation. Thanks for stating the obvious!

 

 

19

jimthegenius, I notice in your picture the spoke shave appears to be running perpendicular to the stringer (or, maybe more accurately, not at an angle). Is this because it’s a spoke shave and not a plane (which red_boards informed me must be run at an angle), or is this just the way the tool was set down when the picture was taken? I’m curious if a convex blade on a spoke shave is narrow enough to avoid having to angle the tool, which I’m kinda thinking might make this a wee bit easier to use than a plane on an angle.

 

Edit: Crap, just saw Huck’s comment. Ok. So I’ll need to find a good spoke shave too. I’ll have to dig through my old inherited woodworking box and see if there are any nice planes or shaves hidden in there amongst the chisels and saws.

 

20

And that’s why you use a spoke shave at the nose (deck side).