Balsa Fish Project

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Location: San Diego, CA, USA
Joined: Nov 21 2006
Posts: 705
Points: 385

Balsa Fish Project

I have started a new project to build a fish made from balsa wood. I have never shaped a surfboard before. I am posting my ideas here to hopefully get some good advise. Throughout the project I'll post pictures of my progress, and then discuss my next steps.

1: Buying the wood: I started off by making a trip to Frost Hardwood here in San Diego. I bought four 10.5 foot boards, and brought them home (see images below). I ended up spending about $325 for the whole lot.

2: Selecting a board to copy: My template for this project is going to be my 6'4'' fiberglass Xanadu "big guy" fish. Since balsa wood is heavier I figure that I will need to pump up the volume a little. My current board is 21'' wide, and I was thinking about making it a little wider. What do you think is the widest that I could realistically go? I'm 6'0'' tall.

3: Creating a Rocker Template: I need to somehow trace the rocker from my fiberglass board to a template. I'm sure there is an easier way, but here is my idea. I'm going to the beach and bury my board sideways in the sand half way down (fins off). When I lift the board up, there will be a perfect outline of the rocker. I'll then put some transparent wax paper down, and trace the outline. I might be able to do the same thing for the foil template too. I'll let you know how it goes.

4: First Cuts: I first put my fiberglass board on top of my workbench, and traced an outline of the top view. I built my bench out of a solid core door so I don't mind drawing on it. I then drew outlines of the boards, and measured how long each piece needed to be. It turns out that I don't have enough wood for all the pieces to run the entire length of the board. I'm going to have to join two shorter boards for my center piece. I know this will look bad, but I don't have enough money to buy another 10.5' board.

5: Jointing: My Dad has a Shop Smith with a jointer attachment. I'm going up to his place in Julian this weekend, and will straighten out one side of each board. Unfortunately, he doesn't have a planer to do the other side. I'm not sure what I'm going to do yet. I think I'm going to have to put a 13'' planer on my list for Christmas.

6: Cutting out the Rocker: Dad's Shop Smith also has a band saw, so I'm going to use it to cut out the rocker on all of the boards.

7: Gluing the blank together: After all the wood is cut, jointed, and planed, I'll glue it all together. Should I glue all the boards at once, or two-at-a-time? Also, what is the best glue to use?

Well I have a lot of work to do now. Feel free to add some pointers, or tell me how retarded I am being. I don't mind.

Joined: Feb 22 2005
Posts: 513
Points: 33

Re: [swied] Balsa Fish Project

Well, it's a nice project.
But I guess if the rocker can be copied that way (bury on sand and so on...).

I can save you a lot of time:
- Take a good picture (2mpx) of the rocker you want to copy.
- Send it to me with the folowing measurements: overall length and thickness if available.
I'll put in CAD and take measurements of rocker and thickness every 10cm, so you can draw it on a roll of paper o directly on the wood. Or even I can send to you the CAD file an print it at KINKOS or any other shop.

BTW: Are you sure you can fit your Xanadu rocker "in" those flat wood pieces???

... sorry about my English, folks.

Joined: Jun 17 2004
Posts: 1172
Points: 94

Re: [neira] Balsa Fish Project

swied: welcome aboard mate. i look forward to following your progress.

if i was you, i'd take neira up on his offer. he really knows CAD.

will you chamber your balsa pieces before you glue them up?

'When I surf I dance for Jesus.'
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Location: 64210 Guéthary, France
Joined: Jun 11 2004
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Re: [oldy] Balsa Fish Project

What's done is done, but templating BEFORE buying wood would have saved you money and trouble: no need to pick up 10.5 lumbers for a 6' something length...

________________________________________

"You should have been here yesterday..."

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Location: San Diego, CA, USA
Joined: Nov 21 2006
Posts: 705
Points: 385

Re: [neira] Balsa Fish Project

Thanks offering to create a CAD file for the rocker template. I took a side-on photo of the board that I am copying (see attachment below). I didn't make it to the beach yet, so I would definitely appreciate your help.

I checked and my wood is tall enough to fit the rocker of the board. My shortest board is 4 3/4'' tall. I put the board flat on a table, and the highest point was 4 1/2''. The length of the board is 6' 4''.

Hopefully the picture size isn't too small. The maximum file size that I could post is 35 kb. I'm not too worried about getting an exact match. I just need an outline that looks like it will be right for the board, and will ride well.

copy_board_rocker.gif
Location: San Diego, CA, USA
Joined: Nov 21 2006
Posts: 705
Points: 385

Re: [oldy] Balsa Fish Project

Yes, I am planning on chambering the board prior to gluing the boards together. I'll post some drawings here before making any cuts. I want this board to be as light as possible, so that it will surf well.

Joined: Jan 19 2005
Posts: 436
Points: 59

Re: [swied] Balsa Fish Project

Hi Swied,


Just a quick comment in reference to the width


__________________________________________________
My current board is 21'' wide, and I was thinking about making it a little wider. What do you think is the widest that I could realistically go? I'm 6'0'' tall.

__________________________________________________

I'm also 6'0" so I assume our arm reach to be similar to mine. I've shaped a few wider boards and found that 21" is about as wide as I can go for my arm reach. Anything wider and I find myself having to reach around the board too much in order to get my arms in the water... resulting in an inefficient paddling action.

All personal, but as yours will be balsa, you'll need a bit more paddle power than your normal board... Don't forget that a fish shape is going to give you more overall volume anyway as the nose and tail is generally wider than other styles.

-Cam

-Cam

Location: San Diego, CA, USA
Joined: Nov 21 2006
Posts: 705
Points: 385

Re: [swied] Balsa Fish Project

I finally made it down to the beach to test out my idea of making a rocker template in the sand. It wasn't as quick and easy as I thought it would be. My first attempt ended up with a cave in. The second time I made sure that the sand was wet and packed down well before lifting up the board. It worked well, and now I have a nice stencil of the rocker for my board.

I took several pictures. Check them out.

Location: San Diego, CA, USA
Joined: Nov 21 2006
Posts: 705
Points: 385

Re: [swied] Balsa Fish Project

Here is the stencil that I drew on the paper towel the covered the hole.

Joined: Jul 16 2006
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Points: 258

Re: [swied] Balsa Fish Project

thats a classic idea! so cool.
you really are using the "surfing environment" for both leisure and labour!

Not quite so "pure", but you should try APS 3000 software.
Take a digi photo from side on as you have done above, and import it into the program and match the rocker curve.
And outline template, and foils, and and and......

It saves me so much labour, and you accuracy goes up.

Kit

Edit: go through the APS tutorials, they help get you started much faster. Ask if you need help.

Location: Corpus Christi, TX, USA
Joined: Mar 18 2004
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Re: [KKSurf] Balsa Fish Project

Here's what I did to grab rockers for my hotwire templates, it worked perfectly, just hope it translates well to text... Should have taken a picture...

1. Get a chunk of masonite as long as the board and wide enough to take the whole rocker, screw it to the side of a workbench so the straight edge is flush with the tabletop. The smooth surface of the masonite will be perpendicular to the floor and tabletop.

2. Lay your board on top of the workbench in such a way that the stringer is directly above and aligned with the masonite edge. Your board will be half off of the table, so you'll have to weight one side of it to keep it from falling off. Looking at it from the side, you should see your board's profile, and below it a long flat expanse of masonite (hopefully the smooth side).

3. Get a painter's mixing stick from homedepot and cut one end into a point. drill a hole some distance from the point (probably an inch more than your nose rocker measurement) and jam a sharpie (or other fine tip permanent marker) into it so the tip protrudes through the stick just a little.

4. Press the stir stick flat against the masonite with the sharpie tip against the surface, and the pointed end of the stir stick at the tip of your board. If you're set up right, this point should be right against the stringer.

5. VERY carefully, move stick/sharpie jig along the stringer to the tail. by making a mark a set distance from the bottom of the board, you are effectively duplicating the rocker. The stick HAS to stay vertical as you make this mark, or you'll wind up with poor duplication. Really the only way to screw it up at this point is to move your stick off of vertical as you make this mark. You could even go over it twice to make sure you got it right.

Now you have your bottom rocker profile.

If you are just looking to get a rocker profile to reproduce that board's bottom, all you do at this point is cut on the line, sand smooth and viola!

If, like me, you want full (top/bottom) rocker profiles for hotwire cutting, read on...

6. Flip over your masonite so the your drawn rocker "bottom" is facing up, and again align it with the workbench surface.

7. flip over your board, this time bottom up, align stringer, weight it. You'll need to do some careful measuring and height adjusting to get the board aligned with the already-drawn rocker curve. As long as your nose and tail points (measured from the BOTTOM of the board to the line) are the same distance from the rocker line, you're set. its not easy to balance a board on the tip of its nose and tail right on the edge of a tabletop, but with lots of stuff piled underneath, it can be done. This is probably the touchiest part of the process.

8. Measure the distance from the deck at the thickest part of your board to the drawn rocker line. Add to that number the thickness of your board (use calipers, shapers sometimes make mistakes on written measurements). This number you get is the length you need to make your drawing stick from the sharpened tip to the tip of the sharpie marker. I found it easier to get the sharpie set in the stir stick, then whittle down the point until the measurement was right.

9. Again draw along the stringer with your stick/sharpie jig, keeping it perfectly vertical. If your setup was careful and correct, you'll be staring at the drawing of your perfectly duplicated rocker profile.

10. if you're doing hotwire rocker profiles, put another chunk of masonite under this one, and drill regular holes along the template, bolting them together as you go along with 1/8 machine screws. More bolts are needed at the ends where the templates are thinner and more flexible.

11. cut both layers with a jigsaw outside of the marked lines, and sand down to just almost meet the line. Eyeball frequently to take out any wobbles induced by the templating process.


Sorry, I got a bit off track on this, but I've been meaning to post up that method for a while. It is a bit tedious, and very "garage", but necessity was the mother of invention on this one, and it does work extremely well when done with patience and care.

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