Constant radius curves

So I’m trying to make some templates and I’m wondering, is there any part of the outline that has a constant radius curve? Or, is the curve always accelerating (changing radius)? I had this bright idea of putting a router on a 10’ 2x4 and cutting out a nice smooth curve in masonite. It made a nice even arc, but as far as the outline of a surfboard, I’m beginning to wonder if the utility is limited. The French curve I blew up to six feet and transferred over to masonite works okay, but the change in curve radius seems a little fast to provide a good template curve.

 

Member everysurfer uses 3 different radii for his rockers, and blends them.  Malaroo uses a portion of an ellipse for his.  For plan shape templates, I draw them freehand, on graph paper, until I like them, then I scale them up using a grid, draw them freehand on masonite, and blend the curve with hand / eye / sanding block.  http://www.wikihow.com/Scale-Drawings-Using-the-Grid-Method

Another member said he designs new plan shapes on the blank, then makes his template off that.  I think member Mattwho did one where he shaped half the board, used that to make his template, then used the template for the other half.  Some people use bent sticks for template curves, Kensurf used a fishing pole because he liked the graduated curve he got with it.  And lots of guys just design on computer, and print up their templates.  Their is also a website with free template files, http://www.blendingcurves.com/temps.  Lotsa different ways to get there.

Thanks. I had hoped to use that 10’ radius curve for the mid-board planshape…and it kinda looks okay. The batten method drove me nuts–didn’t like the nose/tail shapes that resulted, and found it hard to reproduce a curve I liked.

Nice grid on the template material. I hadn’t thought about that, but it makes sense.

Thanks.

I tried bending sticks at first.  I work alone, so I would clamp one end, and then bend.  But it was tedious, and I never quite got exactly what I wanted.  So I just draw on graph paper, 1/4" grid, where 1 inch on the paper = 1 foot.  So each quarter inch square equals a 3" square on the masonite, drawn with white tile-setters pencil.  I use the grid to freehand imitate the curve I freehand drew on paper.  I buy the paper in packs at the dollar store, and go through a lot - its not like I get it right the first time.  But eventually, after I’ve drawn a board enough times, I get one that I like.  Thats the one I use as my reference.

Its an imperfect system, but no worries because then I clean it all up with sanding block and eyeball.  Some guys say its not the right way, but it works good for me.  Once I have a board in my head, I just find ways to get it built, and I’m not always the best guy for advice, because I just make a lot of it up as I go, haha!  So take what I say with a grain of salt, find what works for you.  Here’s a thread you might find useful http://www.swaylocks.com/forums/fiberglass-batten-templates

Oh yeah - and why does this dog have a donut on his head LOL?

http://compositecorner.wordpress.com/2014/07/25/tricks-to-making-a-surfboard-template/

http://www.swaylocks.com/forums/template-radii

From an earlier thread. I do something similar on rockers too.

In regards to combining templates, curves or whatever you chose to call it there is always some satisfaction for me at least in taking a hand planer to a peice of drawn on and cut out mohagany doorskin and adjusting the blade to a fraction past zero and finally getting the last of the highs and lows blended into perfection. The only tools i need for that are my eyes, hands and a environment with contrasting light such as my porch at night with the light behind me. 

Everything above described by Huck and others works.  I have heard of guys using graph paper to get an idea from ones head to masonite; but Huck’s method is the most effective method of that type I have yet to see used.  Sorry you had problems using a batten.  Upon the deatth of my sailboarding brother-in-law I inherited about 20 battens of various lengths flex, thickness etc. that I would never part with.   I can blend any curve with them.  The one method that wasn’t mentioned here is the one that Mike Doyle used once to copy a Pat Curren gun.  Lowel

The great thing about templates is the more you make,

The easier it is to make more.

I should know.

My collection has grown to 200+.

I  have always used the 0.25-inch graph paper method Huck presented to make templates.  I learned it in high school woodshop.

White poster board and a No. 2 pencil will work for a template that is short-term.  Several sheets of poster board can be taped together.  But I like Hucks’s white china marker concept – finally found some cheap on Amazon, also found some white dress marking pencils to try at Hobby Lobby.  But I think the masonite or “door skins” are better if you plan to keep the templates for future use and the template outline can be smoothed out with sanding.

When I can find a long enough stick that has the right flex, I want to compare it with the hand-drawn template method by drawing a batten outline directly over the hand-drawn outline.

EDIT:  I would use 0.25" = 2" or 3", depending on trasfer detail wanted.  Template grid squares would be 2" or 3" accordingly.  After drawing on graph paper, I like to clean up the hand-drawn graph paper shape outline with the appropriate size French curve.

I think some folks around the site don’t understand the type of battens I am referring to.  I have some that are 4 or 5 feet long and so tapered at the thin end that the last foot or two can be wrapped to follow even the most extreme curve. They are flat.  A flat carpenters pencil or a standard #2 traces along their edge nicely.   I usually make my marks at 6" or 12" intervals to mark my width and then just connect the dotts.  I use a shapers square to mark my width at the intervals.  I don’t use drywall nails (like in the Carper Video) or clamps.   I just use the “love handles” God gave me and hold the batten with one hand and mark with the other.  If I am making a masonite template clamps can be used.  A Surform, handplane, paper and a sanding block will clean up the masonite template nicely.

I am guessing you mean the battens like those for a windsurfer sail.  I just do not have and cannot easily get any locally.  I need to look for a long, thin piece of wood trim…

The battens for my old windsurfer sail would have been way too short IMO.

 

EDIT:  In some other thread, somebody had mentioned having some masonite cut into 4, 10-11" sheets for shape outline templates and saving the last 2-4" strip for drawing long curved lines – shape outline and rocker.

Cool template design technique: Multiple lengths from One curve. This can be done with the tail as well. Start by tracing a curve from one of your existing templates on to a new 8’ peace of material. Lay out your modified nose or tale curves on your one basic design. Cut and shape the longest line. Then trace it on to a new peace of template material and set it aside. Cut and shape in the next curve, transfer it on to another new peace of template material and set it aside, and so on. When you finish all the curves, you’re left with one finished template(the shortest of the group) and multiple progressively longer in length templates that you’ve traced, that are ready to cut and shape in. I’ve made as many as 12 different lengths and designs from one basic curve with this technique.

I know I’ve said this before, and sorry for nagging by saying it again.  Surfboards are more than just pretty curves.  To know how the board is going to work while you are shaping it, and what you did so you can copy it, you really need to be able to measure the curves.  And just measuring rocker at every 12" doesn’t do it either.

Templates and outlines can be “faked” by bending sticks, and smoothing it out.  But your design world really opens up when you know what the curve is doing. Is the curve constant, or accellerating?  It really makes a difference how the board rides.

Sorry again, rant over

A parallel sided batten is not much good for producing compound curves that have a degree of acceleration towards the ends. Try a tapered batten for a better result. A handy tool is the bare shaft of a fly fishing rod . If you have any rocker #s to aim for , the tapered batten will blend them nicely into the tip , without any bumps or hollows.

As usual, lots of great ideas from Swaylock’s folks. First things first…the dog’s name is Baker, belongs to a friend of mine who has trained him to be very patient. So the donut will stay on Baker’s nose until he’s given the okay to toss it up in the air and then catch and eat it. The dog is spoiled…even has his own noise cancelling head set for when he flies around in his owner’s Cessna.

The tapered batten sounds like it’s worth a try.

200+ templates?! Sweet.

Wavecraft…how does that work with the multiple curves? Seems like you’ve got the same hip width for all of them.

And Everysurfer…I just don’t have the eye yet for using the computer. I downloaded the Shape3D lite version to mess around with outlines, but haven’t printed anything out yet to transfer over to masonite. And I checked out that thread…looks like you’ve got a nice system.

Thanks for the ideas…off to find a fishing rod and graph paper.

Yes you are correct. In this case I had an old proven 6’6" high performance template with a 19 1/2" mid. dimension … I wanted to make a wider volume 20 1/2" version. I took the template placed it on a new peace of template material then manipulated it to trace a wider version of the curve. Then cut and shaped that new wider template. Then took a new 8’ piece of Masonite and proceeded to project the nose style and dimensions inward and outward

From that point I had what you see in the photo, and used the technique I described above for a new series of nice Wider volume template designs in different lengths. I use a router to cut out blanks with these full length templates.

Here’s a 6’4  I made using one of the templates from this series.

I’m no expert, but in general the outline curve is constant… or it’s on continuous curve. Can it be straighter anywhere on your design? Yes it can.

I’ve made my templates from wp to tip bending my curves with a flexible metal yard stick to dim points; 12" from tips, wp etc…

Main thing is, curves should be how you want them. Or they should
Look right.