shaping my first.

General Discussion
1

Hi guys.

Not done a great deal on my board, but got the shape finished, going to do the rockers and get the foam down to something like I want this weekend. Then hopefully do the rails through the week.

So far so good I think, enjoying working with the surform, get a real feel for it. Got my fin this week, bought a Dorsal products signature fin. Clear, 9" long. Big I know, but I think it will be perfecto. It has quite a bit of flex in the tip, may try it on my mal too.

Thinking of a rolled bottom to vee, slightly pinched rails…

Anyways, any comments, advice, criticism, all accepted.

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2

Have you ever cut rail bands before? If not, or you are worried about asymmetry, I have a method that will give you measurements so that your rail bands will be symmetrical and come out the way you want. Have to go to class right now, but I may be able to post later on the method. It is tedious, but works. Sorry, don’t have a method like it for rocker, I use a hot wire for that.

JSS

3

Interesting you mention getting a feel for the surform… On my #1 I also surformed the most of it but I was a bit dissapointed in not getting my rail shapes the way I wanted, whilst the surform felt in control, it left me with bumps and any attempt to correct bumps with it just mowed foam and left me with new bumps. Maybe just me but on #2 I decided to try a different approach and basically get over my planer angst. Was surprised but once you get a grip on the planer (literally !!) the rail bands come smoother and with more control. I am actually rather impressed with the rails on #2 (see thread in discussion #2 EPS Epoxy for shots). Using drywall screen and sandpaper to blend was also easier, there werent any bumps except for longitudal lines of the bands so long boardlength strokes helped clear those. Didn’t touch the surform once!

Is it just me? Is it EPS? Or do others have the same experience? Am I becoming a planer junky? Yeeehaaa!!

Be sure to show us pics as your board evolves!! thinking of photo addict Chipfish here :wink:

4

Got a mail off the Chipster before I put saw to foam Dave!!!

I’m going to use the plane on the deck for the rails, also on the hull. The blank was only £30 so I’d rather make mistakes now nd start again if I have to.

I’m pretty confident to go at it with the plane, I’m actually really looking forward to the glassing.

Max, I’m going to make one of those little tools that JC uses on the 101 dvd. But please, if you have time, I’d love to hear how you do it. It may be easier for me. Lots to learn. Taking everything in, and filtering what I think I’ll need.

Thanks both of you.

5

OK, here goes.

First, draw 3 cross-sections of how you want the board to look at nose, middle and tail, using measurements from your outline/thickness that you already have. Here’s some cross sections from the Natural Curves website (www.naturalcurvesboards.com). You only need half the cross section, so if you are drawing it, no need to make both halves.

Here’s the same thing with only half:

Then box around the cross section to determine the foam you have now that will be taken away. When you draw this, start with the boxes (the width and thickness of your blank at the 3 places) and then draw in your sections. I did it the other way around on here. Hopefully this is making some sense.

Will continue on another post…

JSS



6

Max. Looking forward to the conclusion of your explanation.

7

Awesome. Right when I hit ‘Send Reply’ for my last post, I lost my connection to Sways. Well, here goes again.

So, now I am only going to focus on one of the cross sections, the middle. Here it is:

To figure out where the top rail bands will be, put tangents to the shape at 45, 60, 75 and 85 degrees. Here they are in red, blue, green and magenta, respectively.

To get measurements for the first rail band, measure from the ‘stringer’ out to the red line, and from the ‘bottom’ to the red line. Here are the measuring lines in cyan (light blue).

Continues on next post…

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8

So, to measure the second bevel, you measure from the ‘stringer’ to the blue line, and from the intersection of the red line and the box (foam) and the intersection of the red and blue lines. Essentially, you are measuring ‘up’ the first bevel/rail band. See pic:

Now, just finish doing the same for the next 2 rail bands: Here’s the 3rd:

And the fourth:

Since there is not ‘belly’ in this design, you really only need 2 rail bands fro the bottom, at 45 and 60 degrees, or 30 and 60 degrees, like the “Fred” tool lets you cut in by its design. So, now what do you do with all of these measurements? Next post will try to explain.

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9

OK, now unfortunately comes the hard part. If you are great at drawing smooth, free curves, then just mark the foam with these measurements for the three places you cross-sectioned (nose, mid, tail) and connect with smooth lines. I am no artist, so I came up with a way to ‘morph’ the cross-sections into one another smoothly. Here goes:

Put the measurements in columns (numbers are not to scale, just what I measured on the screen)

Middle of board section: Width: 5.12 Thickness: 1.65

Rail Band Horizontal measurement Vertical measurement

red (45deg) 4.09 .63

blue (60deg) 3.54 .40

green (75 deg) 2.53 .48

magenta (85deg) .98 1.22

OK, now that you have all of the measurements (you have to do this for all 3 cross-sections), you have to normalize the data to the cross-section width and thickness. Sounds complicated, but it is just taking each horizontal measurement and dividing it by the width of that section (for instance, above, the red rail band’s horizontal factor is 4.09/5.12, and the vertical factor is .63/1.65). Here is what you end up with for the factors for the above cross-section measurements:

Rail Band Horizontal Factor Vertical Factor

red (45deg) .8 .38

blue (60deg) .69 .24

green (75 deg) .49 .29

magenta (85deg) .19 .74

You will end up with three sets of these factors. They will differ some, and the hard part is how to change them along the length of the board so that a smooth transformation between rail shapes takes place. I use Excel to draw smooth curves between them. We now have to establish a coordinate system.

So, now you have three sets of factors, and three places on the board, nose, middle, tail. Usually, this means 12" up from the tail, 12" up from the nose, and on or near the midpoint of the board’s length. Let’s say you have an 8 foot board. So, the ‘tail’ cross section will be at 1/8 up from the ‘very tail’ of the board, the midpoint at 4/8, and the ‘nose’ at 7/8 of the board. These will become relative locations on the board. You should have something like this for each rail band:

1st rail band (red)

Location Numerical Relative Location Horizontal Factor Vertical Factor

very tail 0/8 or 0 x x

tail 1/8 or .125 from measurements made at that cross-section

                  2/8  or .25                               x                            x  

                  3/8  or .375                             x                            x

middle 4/8 or .5 .8 .38

                  5/8 or .625                              x                            x 

                  6/8 or .75                                x                            x

nose 7/8 or .875 from measurements made at that cross-section

very nose 8/8 or 1 x x

All of the ‘x’ places are numbers that have to be filled in by the smooth curve. Once you have all of the factors for all of the positions and bevels, you just measure the blank at all the positions (width, thickness) and multiply the Horizontal factor by width at that spot on the board to get where the measurement is for that bevel, same for the vertical measurement.

I made a spreadsheet to make all of the calculations for me, as it becomes very tiresome. All I have to enter is the board’s measurements and the measurements from my drawn cross-sections, and it spits out everything. I print it, and layout the measurements on the board. I tape off the rail bands with 3/4" packing tape and use a planer to take large pieces of foam away, then use a sanding block to hit the tape exactly. I peel the tape, and you have a bevel, same side to side, and no guesswork involved.

I am no sculptor, and most shapers definitely are. As a student, I cannot afford to buy 3 blanks to learn (i.e. make mistakes) with, so I had to make it count on my first one. That’s how I came up with the method. It takes a LOT of time to do the layout of the measurements for every bevel, but the end result is nice. Here are the first two top bevels, you can see I have started marking the ‘vertical’ measurement for the 3rd bevels in already…

That is the short version of how I do it. I have to get back to studying… If anyone is interested, I can explain more when I have more time.

JSS

10

Well, I can see that my tables did not come out right on my last post, and neither did my pic of the bevels. I’ll have to post the pic later, and I do not have time now to correct the tables, but does anyone know how I can post tables well, or any type of post that uses many spaces to separate text?

JSS

11

Here’s the pic:

The 4th bevel has some wiggles in it, but that is due to some aggressive sanding on my part. I hadn’t started on the bottom ones yet in this pic.

JSS

12

JSS,

can you post/attach the spreadsheet for us?

looks like it works great.

have you thought of taping it up and using a hotwire to do the railbands as well as the rocker?

another poster (cant remember who) said they do this and it works well.

Cheers,

Scot

13

I tried at first with the hotwire, but my cuts came out very inaccurate, and difficult to correct. It is hard for me to keep it on the tape without burning through it, and I was using low wire temps. The hotwire also leaves a ‘crust’ which is difficult to sand through at first, so more errors can be introduced while correcting after hotwiring.

So then I moved to only sanding them (the bevels) in, and finally went to planing followed by sanding. That way I get some planer experience, without messing up too badly. After you do a few of these, you can see what bevels do to the final shape of a board, and you can begin to see how you could shape ‘by eye’. I am still very far away from that, but every board I build I get closer to getting there. I am amazed by the skill pro shapers have, just cutting into the foam, knowing how the final product will turn out. Like really good sculptors and their marble.

I’ll modify the spreadsheet so it’ll have instructions on it, as it is very complicated when you first glance at it. The spreadsheet is made so that you can take measurements from a sketch and it will give you numbers for rocker and outline templates. After you have the outline and rocker templates made, you enter their measurements into the spreadsheet, and it will give you all of the bevel numbers. Or, if you have an existing outline on a blank, just measure it and enter those numbers as your ‘template’ numbers.

Give me around 2 weeks for this. I have a giant neuroanatomy exam in 11 days, and all of my efforts have to go towards it.

JSS

14

cool,

thanks for the feedback on the wire for banding.

good luck in your exam.

scot

15

OK, here it is.

Instead of creating a new spreadsheet, I decided to post one that I have already done all of the hard work for. It is for an ‘egg’ shape, and can be made whatever length you want, it is explained on the sheet, at the top of each worksheet in bold.

Outline is fairly symmetrical for and aft, with a slightly more pulled in tail, and slightly fuller nose, to put more width under chest for paddling.

Bottom contours: It has a slight belly in the nose, morphs to flat in the middle, and then forms a vee that gets more pronounced towards the tail (spiral vee?). Domed deck, soft rails in nose, to tucked rails in middle, sharper/harder in tail area. Anyway, here it is.

Rocker is a continuous curve, apex a few inches in front of middle of board.

If you want to see what Outline and Rocker are like, graph position vs outline or position vs rocker on the sheet with the Chart command.

All of this is changeable if you play with the spreadsheet, to create any board you want. Only limitation is no concaves can be mapped with this tool. Only convex surfaces. For concaves, just map it as flat, and make the concaves yourself.

I had to zip (compress) it to get it to fit here on the forum, but hopefully that won’t be too much trouble to unzip.

If you have any questions, let me know. If you want to know how to create your own, from your own drawings, also let me know, but that will take more time.

I haven’t built this board yet, so when I do get around to it (not for around another 3 weeks), I’ll post pics of how it is done using the sheet, making templates and everything.

JSS

https://swaylocks7stage.s3.us-east-2.amazonaws.com/s3fs-public/1020873_Egg%20Spreadsheet.zip