Balsa Fish Project

General Discussion
1

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.
2

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???

3

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?

4

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…

5

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.

6

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.

7

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

8

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.

9

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

10

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.

11

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…

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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

12

Shape 3D is the best software for designing boards. Plus you can print out rocker profiles. Download a trial copy at:

www.shape3d.com

13

I like the 3D generation you can do in shape3D, great to show whoever your making the board for what it will sorta look like.

But, my trial version period ran out… APS 3000 is free, and i’m poor.

Perfect match!

Kit

14

Ok, you already did the burying thing.

Very imaginative, congrats!!!

Anyway, if you want another source for your rocker you can check the file I did with AutoCAD:

Scaled image to 6’-4".

Drew top+bottom rocker lines.

Took measurements of bottom rocker and thickness every 6" from nose to tail.

Here is the result.

I have the CAD file (.dwg) if you it to be printed by a plotter (it’s 70kb and can’t post it here)

15

BTW, you’re right about the maximum depth of the rocker outiline. I measured a total of 4.6" for the whole stringer.

860×87 12 KB

16

Hola again!

I wonder if it’d possible to do a PU pour foam into that cavity, then lay a wood panel and call 5 of your friends to sit down on top of it for 1 hour. Then you’d have a perfect “ready to glass” 1/2 foam.

Just kidding…

17

you could pour plaster in thereand just lay some wood on top then trace the rocker outline and cut it out

18

With that digital photo of the board and APS3000, I’d have a rocker temp printed, taped, glued down, cut out in masonite x 2, sanded, ready to nail to foam in about 1.5 hours, but I’m a practiced hand with APS. I think APS3000 is the shit.

19

Neira: Thanks a lot for making that CAD drawing. I’m going to use those measurements to tighten up the lines I drew on the paper towels. Next, I’m going to get some masonite, and transfer the outline to it.

I am glad that I posted this thread. There has been some great advice here. I just downloaded APS 3000 and started playing with it. It is going to take me a little while to come up to speed on the software. It looks really cool though.

BTW, my wife went shopping today – it’s the biggest shopping day of the year here in the USA. She found the thickness planer that I told her that I wanted for Christmas. It is a 12.5’’ Dewalt, and she found it on sale at Sears for $200. That is a very good deal! She was so excited, she had to call and tell me. Unfortunately, I won’t have the big surprise on Christmas day, but I am stoked to get it.

Tonight I’m heading up to Julian to start make some cuts with my Dad’s Shop Smith. Hopefully, I will get all of the boards jointed, planed, and rocker cuts made this trip. I’ll be back on Monday, and will provide an update then.

20

I went up to Julian last weekend, and brought my balsa wood. I also brought my new DeWalt thickness planer. The planer worked great. It is really going to help speed up all of my wood working projects. As I mentioned before, I don’t have a jointer. My Dad has a jointer attachment on his Shop Smith, which is why I brought all of my wood up to Julian. It turns out that the jointer attachment only has a four inch blade. All of my boards are wider than that. The table length was also pretty short. Things did not look good.

I really wanted to get this project going. I decided to attempt to run a board through in one direction, rotate it 180 degrees, and run it through the other way. This seemed to work OK. I made several passes until it seemed like all of the bow was cut out. I then ran the board through the thickness planer to create a smooth parallel side.

I did this procedure with a second board, and then put them side-by-side. They were closer than before, but it wasn’t a perfect fit. This troubled me, but didn’t stop me from trying again on a third board. I had the same problem with this board. Ghhhrrrrr. I’m not sure what went wrong. The only thing I can think of is that the jointer table is too short. I didn’t measure it, but I don’t think it was longer than three feet.

I was at a cross roads. I could continue to make a whole set of imperfectly fitting boards, and try to squeeze them together with clamps and glue. The other option was to stop and think it over. Jointers are expensive, but so was the wood that I bought. I chose to stop.

At this point I am thinking about purchasing a jointer. I have wanted one for a long time, but never felt justified in spending the money. I usually try not to cheap out when buying power tools. I feel that the better brands like DeWalt, Jet, Porter Cable etc. are worth the extra money since they end up lasting longer. A good jointer, however, will end up costing over $1,200. I’m thinking about going cheap this time. I found an 8’’ 2 hp jointer for sale at Harbor Freight. It is made by a company called Industrial Machinery – whom I have never heard of before.

Here’s the ad for the $400 jointer: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=32966

Here’s and ad for my dream jointer for $1250: http://www.rockler.com/product.cfm?page=17103

Am I being stupid to consider the $400 jointer, or is it really a good deal?