Help with concave on longboard

I need some help on how to shape a concave (around the nose area) on a 10 foot longboard I’m working on.  I found some threads on using a plane to take down the stringer but I’m really not sure how to shape the foam.   I have a spoke shave that I could use to plane down the stringer.  I wondering does anyone have some suggestions and steps on how I should tackle this.   Also how far back should I position it from the tip of the nose.  So far all the boards I have shaped have been flat bottom so this will be my first concave and I don’t want to screw it up!  Thanks.

Hey Max, First, draw out the concave whether it is teardrop shape or ovoid like a football. Draw center lines both ways and where they intersect will be the deepest area. You don't want to go more than a quarter inch deep. You can scoop out using a disc sander or by hand with a sanding block. If you have the capability, make a convex block approximating the arc to be taken out. Attach sand paper and have at it. Blend out to the edges. To be safe if you want, at the center cut a 1/4" deep groove to use as a reference while blending. I'd stay about two to two and a half inches from the rails to allow for a good lap on the glass. I also reccommend making templates of the curves both ways; nose to tail, and rail to rail for future use and consistancy. With the templates you can't go wrong. GOOD LUCK!


Thanks!  I will give that a go. Just wondering where should the placement of it be, should the start of the concave start around where the rocker starts becoming “flatter”.  On my rocker profile thats around 2 feet from the nose.

I do blended teardrop shaped concaves one third the length of the board.

Hi Max, What Nj Surfer said is a good rule of thumb but, it really depends on the rider. Size, weight, etc. For most, one third will do fine. Sounds like you have a good idea of doing it. The flatter spot is the right transition point.

Thanks guys this is alot of help.  I have one last question.  I’m wondering if my rails are thinned out enough.  I’ve attached a few pics.  I’m using greenlight’s rail band’s guide, do they seem ok?  I haven’t finished blending them yet but the shape and thickness is roughly where they are going to end up.  Thanks.

Looks good, shape is nice and rails coming along also. You could use a little more foiling but it is not necessary; its all about what you are trying to achieve with this board? nose rider? hplb? headstand? remember though dont go to thin if its your first board, its better to have a thick board that rides, than i thin board that just sinks. Single Fin or 2+1? Also i plane 1/8 off the stringer, draw my outline of the concave, hand sand or greenlight came up with this new concave rasp that is awesome. perfect concaves everytim… anyway than proceed to blend in the concave with a soft pad.

question;    What is your thickness at the nose one foot and two foot from the tip of the nose..    Also one foot up from the tail. 

I just measured it and it is

nose: 1 foot = 2" and 2 feet = 2 3/8"

tail: 1 foot = 2"


hey a2tall thanks

What my plan for this board is just a general purpose board for gutless surf, I have a fish but that isn’t cutting it this summer I find. I’ve been riding a few years so it’s not my first board.  I always wanted a longboard but I found it a pain to take around with me.  It is going to be a single fin (fins unlimited) but I had contemplated glass on two small side fins.  I won’t get a chance to work on the board for a few days but I’ll post my attempt LOL

definately foil it more. if it were mine, the nose would be around 1.25-1.5 and the tail about the same. not only that, but the tail block andnose tip look VERY thick so maybe do somemore shaping. just a tip before you glass it and can't change your mind. good luck

Good question M'Ding...plenny tik.

Max, How do the rails look to you? You have ridden other boards, how do your rails compare to those? Maybe turn them up a little more in the front half unless you want hard all the way. Turn them into more of an egg shape, it's up to you. To me, they look like they could use a little work but for you?? The tail is pretty thick too. Might want to do some foiling back there unless you are a bigger guy and want the float. Also, try putting in some boxes for the side bites so you can go 2+1 or single. Good Luck, Keep going.

Thanks guys.  This is really only the third board I have shaped so I’m still kinda new at getting the rails right, I think I have tend to shape them too “thick”.  I will thin out the tail and the nose.  I weight 130 so I’m pretty light so you are right that I should thin it out.  I do have a question on how to foil it, the stringer I created myself from some thin plywood and glued block EPS to it.  All the previous boards I have shaped have been stringerless. So I’m just wondering what is the best way to take down the stringer with out tearing out the foam.  I have a spoke shave and a block plane, do I need one of those small stanley planes as well?

Also where is the best place to take off foam/stringer top/bottom or combination for the nose and tail, I know I should be keeping the lines clean.  The middle is 3" thick so if I’m making the tail and nose thin I’m just trying to figure out where I should remove the material, I don’t want to throw the rocker/foil out of wack.   If I remove it from the bottom it’s going to add to the rocker, so should I be removing it from the deck?  I know this sounds like a newbie question but I’m not sure.  thanks again everyone

Max, good questions, shows you are thinking. First and foremost, go over your bottom rocker and make sure it is where you want. If you need to, get some rosin paper or roofing felt and scribe the rocker from the blank on to the paper and stand back to really look at it. Does it have smooth or abrupt transitions? Do your concaves before thinning. This will keep you mindful of thickness when foiling the nose. Spend time to dial this rocker in and then move on to the foiling of the top. Use your mind's eye. I'm sure you've looked at LOTS of boards. Take plenty of time to stand back and stare at it. Think about how the water will run along all the curves. Are there bumps or dips anywhere? These will cause the water to hang up. Use long strokes or, "blocking" when sanding. This will seamlessly transition one curve to the other. If there is something that catches your eye, odds are it has to be blended. Take your time to look at it. From all angles. Lights on, lights off, whatever it takes. Don't take off too much at one time. Little by little blend it in.  As for the stringer, the block plane will work well, as long as it is sharp. Take a little foam away and then the stringer. Small increments until you get where you want to be. You can do it. It ain't a race. Take the time.

Max-  My thought was that you can thin/foil the nose and tail both.  Generally on a long board I try to put my thickness(float) in the area where I paddle.  Generally defined as the area between my shoulders and knees if I were to lay on the board in a prone-paddle position.  That would  more or less be the center  of the blank.  At the tail figure out where your fin box will be placed, usually 5 1/2 or 6" from the tail.  From that measurement you will need at least 1 1/8" thru the fin box area. This will insure that you don't rout your box thru the deck. Those are the parameters that I work around when I shape and foil a longboard. At the nose you can go as thin as you want.  At the tip 1 or 1 1/2" is ok  and you can foil/taper back from there towards the center of the blank..  Keep in mind your concave and its placement.  You don't want to get it so thin at the nose that you snap it off trying to duck dive.  As someone mentioned you could use a little more foiling and blending of the rail.  Behind the fin box I thin my tail out the last few inches and harden the rail in the last 16 inches of the tail.  Just some general guidelines and personal preferances.  The first two;  thickenes in the paddling area and thickness in the fin box being the most important.  Hope that helps.   

PS----I like the small Stanley.  They are usually sharp enough to cut ply stringers no sweat.  Take the stringer down first and then block sand/screen the foam down level to the stringer.  If  the stringer doesn't cut well from one end go to the other end and plane in the opposite direction.  First couple of cuts you'll get the feel for it.  When you think you are all done with your blank take the stringer down one last time flush or below the foam.  Then screen the foam down to the stringer removing any tears.  Write you dims and name on the stringer; stand back, and admire the work of your hand and eye.  Lowel

Thanks McDing and tblank.  I’ll keep at it this week, I’ll post some pics of my progress!

I really like the shaping stands.. so simple and effective, very creative!

Looks better. that first picture looks like you need to foil a tad more. What I would suggest is that you go down to your local shop and check out some foils of longboards there. good luck

So I thinned out the board some more like you guys suggested.  I have the nose at the 1 foot mark down to just under 1.5" and from there it tapers down to the nose. At the tail I have it down to 1.5" at the 1 foot mark, I wanted to make sure I left enough for the 1" deep fin box.  I foiled the rails more and blended it into the nose and tail after thinning it out.  Do the rough rails look ok from my pics, do I need foil any more before final sanding?  I’m going now more for a 50/50 rail.

Also what kind of glassing schedule should I use, I don’t want the board to be too heavy but I also don’t want it to ding easily.  I was thinking 10oz on the bottom and 6+6 on the top?  All my previous boards were glassed 6+6 deck patch with 8oz on the bottom but they were all shorter boards, they seemed to be durable and not too heavy.