What exactly happens when you cut a board from a bigger blank? Say 2” bigger for example, it lowers the entry rocker a little and pushes wide point forward? What else?
The deeper you cut into a PU blank, the softer the foam gets, and the easier it gets pressure dings.
I mean design wise what happens? Is there a way to calculate how much further the wide point will be and is the tail affected at all?
A board can be shaped from any blank big enough to contain the shape, changing rocker can be an issue, but if the rocker chosen will fit in the blank chosen, its just a matter of shaping. Normally I would try to do the majority of the shaping off the bottom when possible, so that an acceptable amount of the tougher surface foam remains deck side.
I shaped a 7 - 2 board from an 8 - 2 blank, I just chose where I wanted to cut the nose and tail according the rocker I wanted, layed my template on, cut the outline, and shaped it. The wide point is where I designed it to be, it had nothing to do with the wide point of the blank.
FOam is way too soft to use as a cutting board.
All the best
This post above, is the perfect answer to POST #3. If you are truly a shaper. If all you do is take the skin off of a close tolorance blank, then not so much. Kudos, Huck.
What Huck said. Rocker and foil being probably the most important parts of a board, choosing an oversized blank for a project allows you to position your template where it will match desired rocker and foil the best.
I try to get my blanks to fit my desired rocker and max thickness so I’m not taking a lot off of either the deck or bottom. Sometimes that takes a little creativity. Being able to map the blanks on the CAD helps a lot in determining which blank to order, what rocker adjustments - if any - and where to put the template on that blank when shaing it.
On the last midlength I built I was building a piggy singlefin egg, so I sawed 8" off the tail and 2" off the nose of an 8-9y blank in order to move the apex of the rocker back to where the wide point was. The rocker and distribution of what was left over was perfect for my application. I just flattened the deck rocker near the nose a bit and brought the tail thickness down to get the foil I wanted
Moving a design forward or aft is key to getting what you want out of an oversized blank. Sometimes the only way you can get the desired rocker, thickness and foil in a shape is to go to an oversized blank. My preference is always when time allows to order a blank that is rockered close to what I want and then go from there. One of the best shaping videos around that demonstrates how to use an oversized blank is the Ben Apia shaping video put up by Grant at Fiberglass Hawaii. An oversized Fish blank becomes a High Performance Shortboard.
McDing is right. This video of Ben Aipa shaping a board from an oversized blank will teach you a lot. Ben’s health has been on the decline and his legs are weak, so he may never shape another board again.
What terribly sad news of Mr. Aipa. He sure made some waves in his heyday…in many ways. I saw him in a shape shack working with a younger guy. He came in, put his eye to the blank, and looked at him and said; “more work” and walked out. Such a vibrant man. All the Best to him and the Aipa family.
Sorry to hear that. He has had some pretty good working relationships with guys here on the Mainland. He used to come over every year and shape for Stan Fugi at Ventura Surf Shop. Terry Senate used to shape his Mainland boards back quite a few years. When he was honored a few years back at the Board Show, Terry was one of the judges. Great guy. Always willing to talk a little story.
Yeah, Ben is a great guy. He mentored quite a few people over the years. As scary as he could be in the water, he was always easy to talk to and willing to share his knowledge. He was honored with a star on the surfers hall of fame in Huntington this year.