beerfan, these are some good questions. I have just done a single concave for fong, but we have not managed to test the board out yet to see how it goes and feels underfoot, cant wait to learn from it. I stated it about where you suggested and finished it in front of the fins, the deepest part for me was around the front foot, only did that because I notice that fong drives off his front foot a hell of a lot.
I aint got much idea, can you tell, but once I get this board tested out should be able to give some feedback mate.
Looking forward to other peoples answers on this one for sure
Keep it simple if this is your first go at shaping concave. Start about 12''- 18'' from nose and run it out in fin area. On a wide tail a slight V off the tail will help it go rail-to-rail. Deepest part of concave should be between your feet, but don't get too fixated on that, just try and get a smooth, flowing bottom. Following the outline (re concave ''shape'') is normal, functional, and simpler to do. How you rough it in is up to you, but you want to finish with diagonal blocking to blend.
i have an inkling it makes a lot of sense, but i can’t seem to bridge the gap yet between the intuitive and the methodical while thinking about it hehe
Thanks everyone, already have a oicture of what i need to do. My 6'6'' egg will have a very flat rocker, which is what im after, but i may add some single concave to it. ]
Mike, what is diagonal blocking???
Cheers guys, have a good one tomorrow. Im sipping ( gulping? ) on an american wheat, bloody nice!
Well, I wrote a somewhat detailed explanation of diagonal blocking, but the spam filter blocked it. I even tried adding it as an edit to previous post, no go. It'll probably let this through, testing 1 2 3.... LOL.
I tried to ask the exact same question, “What is diagonal blocking?” and got spammed out enough times to give up. Someone finally gets the question in, now Mike gets spam-blocked. Funny stuff.
I’m interested in the “diagonal blocking” idea as well.
The way I do it: If it’s a deep concave, like a bonzer type concave, I’ll rough it out with the surform. Then I’ll go to the narrower padded block (I have a wide one and a skinny one) and on the inside of the concave, the side against the stringer, I’ll hold the block parallel to the stringer, but sweep it back or forward at about a 45 degree angle toward or away from the deepest part of the concave. Then on the outside of the concave, the side against the rail, I’ll hold the block parallel to the rail and do the same thing… sweep at a 45. I like to finish them with one of those little square sanding pads that 3M makes.
That's pretty much it, nj_surfer. I don't distinguish between inner and outer part of concave (wanting to blend it all), and I wouldn't get a surform anywhere near a piece of foam (lol), but you definitely have the basics of the technique spot-on.
It goes back to the thing about a straightedge laying flat when placed diagonally across a concave.
Oh yeah, get the bigger (like 9'' long) drywall sanding flexi-block from 3M, snip the corners off with scissors or razor blade, and try that instead of the smaller ones, for finishing.
for me, it’s harder to pull off a nice single concave without flattening the the center rocker… always a fun challenge, takes some vision & forethought but I’m probably overthinking it
Could you explain the performance differences between the concaves that go all the way out to the edge of the rail and the ones that end with a 2-3" flat panel prior to the rail. I have only used the single concave/flat panel that was inspired by one of your Coils and have been quite pleased with the results.
Hi CJ, the concave that doesn't ''hook'' the rail is a little more forgiving, but keeps most of the attributes of the big single. Kirk and I usually shape that into boards with a little more width to keep the width from hanging up. Glad it's working for you!
