machine shaping

just a question about the process.

do all shaping machines do most of the cutting from the deck? or are there some that allocate it 50/50? or some that cut the most from the bottom?

i’ve been doing a lot of delam repairs, and am curious as to whether the machining/overshaping of the decks might be a factor in why poly boards are so quick to delam/buckle/break.

what do you guys think?

Smart question.

I suspect it has to do with judgement calls made by the set-up guy based on the board/blank fit. They have to know where the board fits within the blank. I’d guess there are times where a blank has a slightly straighter rocker than the board, especially if the board has a turned up nose. If that were the case the operator would have to push the board to position in the blank to the bottom in order to keep the nose inside. That would remove more foam from the deck than bottom.

I suppose it could be the reverse also.

If you have a quick look at the APS/AKU program, you can see that you position the board in the blank yourself, so it should not cut any more from the deck than the bottom (user error if it does…) I suspect that Shape3D has much the same features, a bit uncertain about SurfCAD/DSD machine.



This is good stuff and a great question. Hopefully the newer poly foam available now(and in the future to come) will not have this problem no matter if you take it off of the deck or the bottom with a computerized planer or something done in your backyard with a chisel.


That’s true if the rocker of the board is similar to the rocker of the blank. But if the board has more rocker than the blank, the operator would have to position it lower in the blank to keep from cutting off part of the nose or tail. At least that’s how I imagine it.


Ideally, if you are getting a particular board cut on the machine, it was shaped from a certain rocker and it should be machined from that same rocker.

KKL has a gazillion rocker sticks indicating which programs will cut from that rocker.

If the master and the new blank are glued to the correct rocker, there will be an absolute minimum removed from the deck, perhaps as little as an 1/8 inch.

This lets the meat of the shaping be done to the bottom of the blank.

Boards that get a lot removed from the deck are not the rocker for that program.

I’ve been using shaping machines for about 2 + years now. Initially the DSD machine and Matt Ambrose’s APS machine since December 2005. Matt and I go to great lengths in selecting the correct blank for each file (shape.) He takes the absolute minimum off the decks of the blanks - the remainder of the foam comes off the bottom. Just as in close tolerance shaping with a planer, it is the responsibility of the shaper to determine the correct deck rocker for each board and purchase and acquire blanks that match the deck rocker of the finished board. If “stock” blanks don’t match their deck rocker it’s the responsibility of the shaper to design and acquire blanks with appropriate custom rockers. It may take a some planing, thought, and time but it’s no that hard to do it right.

Kind regards,

Steve Coletta

By poly do you mean urethane or styrene?

I thought styrene blanks were more uniform in density so it’s OK to cut deep rockers into them?

Quite an important question since my rockers are pretty unique for the board dimensions (2.5; 5.5 over 6’ with 16" nose and tail), so it’s more sensible for me to cut from a an oversized block of styrene than to get a urethane blank made for the low numbers of boards I do.


That’s true if the rocker of the board is similar to the rocker of the blank. But if the board has more rocker than the blank, the operator would have to position it lower in the blank to keep from cutting off part of the nose or tail.

On the other hand, could you do it any different with a planer if the boards profile does not match with the blank? If you do you just end up with a different board…

it seems the consensus is: that if the shaper running the machine knows what he is doing, then, a machine shaped blank should have no more cut from the deck than if that same shaper did it by hand.

thanks for the very knowledgeable insights.

I run an APS machine. If the deck rocker of the blank matches the deck rocker of the design file, you can skin the blank with a precision I have never seen a hand-shaper able to accomplish. You can literally skin the deck at the shallowest possible level. It behooves the operator to take as little of the deck off as possible. As in insurance policy, against rocker variations, etc, I like to have room to move on the bottom. (deck is milled first to 130 degrees) If I have the design sunk way down, when I flip it and run out of foam, I have no option but to thin the design. Not good. I want as much foam as possible on the bottom of my blank when I flip it.

It is true that shapers will frequently bring you a blank that doesn’t have deck rocker to match their design. They tell me to cut it, I do. The only way I have of accomplishing that is to sink the design, or tilt it nose or tail down. But, I always start the deck cut as shallow as possible. The only exception would be some of the extra thick, EPS blanks. Many of the post Clark foams do seem to be denser towards the core than Clark was. But the guys making the blanks tell me they are still stronger on the surface.

And boards have always broken and delaminated. And many is the shaper I have seen mow the crap out of a deck with his Skill. Once upon a time, the 2" thick single 4 glassed sanded finish board was pretty rare. Perhaps that has something to do with it as well.

Walkerfoam since1959(pu) has a constant density through out you could plow an inch of the deck no problem and a handful of otheres that can be overshaped have been around before “Willy Wonka” closed up shop…To me CLARK just had a shinny product good plugs and rockers but crap foam

Walker foam may have slightly more constant density but not by very much in comparison to other blank mfgrs and is actually much softer and heavier once glassed than most other top blank mfrs now in the game. The quality of Walker foam fail in all the other critical areas. It doesn’t matter if you can plow into the foam if the rockers aren’t on. Being either a hand shaper or if you are machine milling blanks having the correct rockers are KEY to keeping your shapes accurate for your customers. For hand shaping, accurate rockers and correct indexing is even MORE crucial than for machine milling. If you can’t glue up rockers accurately what good is the foam? I just milled and shaped a batch of Walkers today, what a major PITA. 80% of the rockers were wrong. Even if I tripled my labor fees, at the end of the day it would still be a losing endeavor. I wish them well. I hope someone close to them can instill how critical this is to everyone that shapes either by hand or machine.

I would rather shape a blank that may be slightly softer in the center but has consistent glue-ups and accurate rockers. In that way you are barely skimming the deck surface for strength and milling the bottom to thickness. Using this method the milled blank will still be stronger than a walker blank.

exactly…joe shmo dosnt need consistency he needs forgivness…"CLARK FOAM THE INDUSTRY STANDARD"great for manufacturing a consistent line of boards. All im saying is that you have to no what your doing,close tolerance blanks are the balls but do they have to be soft “we” should be ordering blanks to a costomers specifics not cause your worried about hitting soft foam

ok, I don’t know joe shmo but I forgive him. not sure what your getting at but Clark Foam is not relative and is not a standard anymore. atleast to anyone I know and deal with. close tolerance blanks is dead. you don’t worry about hitting soft foam these days. it’s not really an issue. it’s rockers. rockers rockers. did I say rockers?

If you use polystyrene boards then it’s probably not going to make any difference. And I thought polyurethane was supposed to be the same density throughout now days?

The problem is not the operator running the machine!

Shapers are the problem. Their are shapers who have shaped for years however still to this day do not understand rocker nor are they willing to understand.

With the abundant supply of 2nd’s (Blanks) board builders bringing these blanks to cutting houses expecting to squease more money out of a dying board market.

Unfortunately the cutting houses suffer as well as the end user. Blanks with the correct rocker take 15 minutes to mill top and bottom including set up. Average price is $25.00. You have the cost of the machine, operator, general overhead. 4 boards per hour is the target for a cutting house with a single cutter head. When you bring a blank not intended for the board to be cut it can take up to an hour per board plus the deck gets plowed and weakens the board. Also your chances for rocker fallout are greater. If you shift towers to make the blank fit you distort the rocker & thickness flow of the intented model.

The major board builders cut all their boards on blanks with matching rockers. They demand quality every step of the board building process. Those who try and cut corners maintain a low volume of board sales and a questionable reputation. It’s not worth it. Make a rocker stick of your board design and make sure the deck line of your blank matches your model… If the blank doesn’t fit don’t cut it!

So glad I’m not the only one that feels that way about Walker. Except I don’t believe they even manage to hit the rocker 20% of the time. I hate the damn things. I have been threatening to charge a $20.00 up fee for each blank. And that isn’t enough. It is a major pisser when I take the time to measure up each blank, alter my closest blank file to fit, test cut the blank, and then, after all that, find that my design file won’t fit inside the blank no matter how I place it.

I can’t believe anyone over there is even trying to nail the rockers.

yup! I realized life is too short. don’t need any more of this type of bs. no more.

Yes, as mentioned, that’s how it works in our software. The board is positioned in the blank, so either shaper/designer or the machine operator has the flexibility to put the board where he wants. The goal was a flexible system that was mainly designed to just skim the deck of the blank. But our T. Rocker and N. Rocker features does give designers the option of changing their design a little bit to fit into the blank. This is something up to the shaper’s judgment, some do it, others wouldn’t think of it.

Ideal situation: Everyone uses the right blank for the board they designed.

Reality: Doesn’t always happen all the time.

So, work arounds are required.

As mentioned, this isn’t really an issue with EPS or and is becoming less of a problem with PU. Scott Saunders from Just Foam has told me that he encourages his customers to over shape the decks if they want, due to his uniformity. I personality don’t have a lot of experience with his blanks but that’s what he’s saying.

Blanks with thin noses and tails greatly limit that flexibility, in our software, it’s clearly seen and you can also see that in many blanks the deck can still be skimmed where the surfer’s feet go.


Aku Shaper