how do you shape a single concave into a shortboard and do you shape in the normal rocker that you want and shape in the concave OR do you accentuate the nose and tail rocker to compensate for the single concave?
forgot to ask about where the max depth should be
First you take your knuckle and knead it on your cockholder while accentuating the obtuse sack angle. Then when you almost have the concave brashed into the beefcake you then rub with fast motion lotion from anal.
WRONG! Thoroughly wipe off your mansweat with the protracting device before you do the knuckle thrust.
OH MY GOD! Have you all forgotten the code of the MASTER SHAPER?! In retort you must always refer back to MASTER SHAPER #00017 and the intricacy of the lattitudal fecal plugger plane-thruster tool. When inside the vortex of the sack angle you must emulate #17’s mad concaver bitchslap method. Duh…
Not appropriate man! Sure would be great if we could keep this site pure! Aloha.
I don’t know, I got a dam good laugh from it. Anyhow, for what i know shape your rocker then add the concave. Most of your concave (in my opinion) would be in about the last 2/3rds of the board anyhow. The nose should be flat. Your choice to run the concave out the tail or make it flat? -Jay
Thanks
You KNOW that you are not allowed to even MENTION the CODE OF THE MASTER SHAPER. What were you thinking???
This is Master Shaper #52134: you have been ex-communicated. Turn in your Fred Tool your finished.
jason- since only a couple people seem to actually be interested in answering your question, try the surfermag design forum. (it must be smart ass day or something ?) there has been a lot of talk on the forum about concaves here and there. check the archives there, and you will find some interesting discussions. it rambles here and there sometimes, but lots of good stuff. http://forum.surfermag.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=4;t=000284#000001 http://forum.surfermag.com/cgi-bin/ultimatebb.cgi
Thanks Brian, yeah sometines i think this place needs a moderator.
Hi Jason, well if you haven’t already cut into your blank, try to relate the depth of your concave to the width of your board. ie the depth should be proportional to the width at each point across the planshape. eg an 1/8" at wide point and 1/16" at the nose and tail where it is 9" wide. This approach is best for learning about the rail to rail influence of concave, because you wont create a vastly different rocker on the stringer as compared to the planshape. Importantly though, try to avoid any flips at the tail, just blend the tail rocker further and further back into the centre rocker untill it dissapears. If I were you I would tape up your skill planer depth control to a fine cut which only just cuts at the centre of the board (ie after you have done the rocker) if you have to think of you hand control for the depth of cut, you will miss out on one key aspect of rocker shaping which you will learn from hearing and feeling the depth of cut as you go from lesser to more curved areas. hard to explain, sorry, and good luck, greg W, ps try a standard planer if you can get one.
jason, I have had success with making a “block” on a bandsaw that reflects a cross section of the desired concave. once my block curve is smooth and fair, I glue a 50 grit peice belt sanding paper to the curve. then with a bit of time and a good shoulder workout I run the block up and down the board starting on the stringer. As you get deeper into the stringer your concave will get wider until you reach the desired depth. Stop short of finish depth, and switch the paper over to a finer grit and finish. when your done take a block plane to the stringer to clean it up… I hope this helps. Jake
Going from talk of needing a moderator of useless responses to advice from the best shaper of concaves today (at least that’s what I’ve heard). Gotta love this place. Thanks again Swaylock, Rob Olliges
WOW! Hey thanks Greg! Lots to think about but im gonna try it.
yup, rob called it, and thanks greg for your willingness to share your experience and knowledge ! brian
When shaping a concave into core material, you define at least two rockers, the primary “normal” rocker arc and (usually) a flatter, central camber. Plus, the deeper the concave, the more it benefits from contrasting contours, such as rail chines, which can balance out/improve a concave`s handling characteristics. The addition of chines creates a third rocker profile, which follows the template, helping to define the rail contours. When shaping complex contours, thoughtful planning is everything… This image is shows a simplified representation of 3 rocker lines flowing through the running surface of a triplane. 
My pleasure. And although what Jake was suggesting lacks the movements which give feedback, he is exactly on the right track in terms of the relationship between planshape width and concave depth, (possibly though, not so much by plan but as a by-product of his technique) ie if the diameter of the concave (ie if you imagine it being part of a large circle) is the same from nose to tail, then the transition of lift into bite (the two key elements of concave) will be very smooth from nose to tail. If the rocker is smooth too then you have a fast responsive predictable board, with huge sweetspot. When one gets really good at understanding concave from doing extreme experiments like dale sure seems to have, then you can try breaking rocker at point and running the concave more deeply thru this rocker bend. Ideally you try to sense the rocker and the concave at the same time. Greg W ps hi to Dale,Rich,Loehr,Rob and Mike…he is Swaylock isn’t he…Please email me man, via Dale if you can. want to do something on this site in my design mag if poss.
thanks Greg, I was just trying to “low tech” it. to get more into adjusting my introduction and termination of a concave I wall take a small drill bit 1/16 of an inch or smaller and tape off a “plunge depth” that I want to get to along the length to the stringer, then as I remove material I just keep checking to see if my pilot holes are still there. I have a pretty nice CAD program at work so I can lay the whole stringer cross section ahead of time and then when I am in the bay it is a matter of transferring the data it has been a good lesson in trial and error, but I am getting close to a profile that I am happy with Jake