I consistently hear about surfboards with concaves, double concaves, vees, etc. I was wondering what tools do shapers use to create these bottom contours, and how do they keep them consistent throughout the board? Any information is appreciated. Thanks Brett
As for me i use the planer with light passes and a series of curved sanding blocks.Production shapers sometimes use a grinder with a power pad but it is pretty tricky.Just take your time. R.B.
Hey Brett, I just made a couple of concave tools for a shaper friend who says they work just fine and he’s been shapin’ more than a minute. I’d be glad to send you photos. They’re pretty simple and I’m sure you could make them youself. Cleanlines if right on! A perfectly true bottom configuration takes a lot of patience and a light touch and a very practiced eye! Good-on-ya, Rich
Ive done a couple of bonzer type concaves that are about 3/16" deep with good results. I draw out lines where I want the concave to go, then use a half round surform taking side to side sweeps. The concave starts off shallow at its furthest point toward the nose and deepens as it goes off the rail in the tail area. I dont run the concave all the way to the stringer. I leave an area about an inch wide along the stringer the length of the concave that acts like a spine. This spine is like a radiused peak that the board can roll rail to rail off of. I usually add a bit more vee in the last third to compensate for the loss of foam, so the spine is higher than the rails.
I would like to see the pics of the concave tools as well. Thanks
I would post a photo here but I don’t know how to do it so I’ll put it in resources when I have the time later today or tomorrow. I can email a photo of what made in an attachment if you’ll send me a brief request for it so have you email address to send it to. Mine’s above. off to work – Good-on-ya, Rich
Call General Plastics (Tacoma, WA) or Coastal Enterprises (Orange, CA) and ask for some samples of high density foam. Ask for their bigger sample panels. These sample panels work great to make tools out of. There lower weight (4 to 8 lb) foam work great as a clean up abrasive on shapes also. Jono
“This spine is like a radiused peak that the board can roll rail to rail off of. I usually add a bit more vee in the last third to compensate for the loss of foam, so the spine is higher than the rails.” Can you explain the “adding of vee”; are you talking about keeping your tail foil thicker at the beginning of shaping, to compensate for what you take off when adding vee and the concaves later? Second question for anyone: vee is obviously visibile at the tail, but how does it begin to flow from the side fins (or from deeper towards the midpoint)? Is it begun outward at the rails and then worked gradually toward the tail and stringer at the center fin (which would leave a u-shaped area noseward from the center fin that’s not vee’d), or does it travel completely across the board, rail to rail, in slight degrees, to the extreme point noticable in the tail? I also wanted to ask if anyone knows what Jim Banks is refering to on his site when he uses the term “precise tapered vee”. Thanks.
I meant that I just shape in a bit more vee, say an eigth of an inch more than I usually do before I shape in the concaves. No extra thickness is kept. The type of vee that has worked for me is one that starts a third of the way up from the tail, peaks right around where the forward fins on a thruster are set (say 12" up from the tip of the tail) then flattens (though not completely flat) off toward the very tip of the tail. Bascially the bonzer that I did looks like a 70’s Bing Bonzer with a thruster set up. I really didnt know what to expect, but was pleasantly surprised with the results.
Well I aint a hydrodynamic guru but I know how to shape a vee.Its just a shallow railband on the bottom,the planer pass starts 1/3 from the tail.Start cut at zero and open to desired depth.It increases the rail rocker line.I have seen to many guys try to sand or surform vees in…just causing a big bump in the stringer.Just an old geezers opinion. R.B.