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???

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...

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.

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

www.shape3d.com

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)

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...

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.

There's a better trick than that for making two boards match each other. Especially if they're soft like balsa & will yield to a little clamping. Less wood wasted too...

Set your table saw fence the width of the first piece. Set your blade height to about 1/16" taller than the wood is thick.

Make some shims the thickness of your table saw blade, as many as the number of clamps you have. Not wedges like shim shingles, but even-thickness shims. I like them long, like 8-10" so they're easy to grab but also keep your hands far from the work. Hardwood. I'd make them about 1-1.5" wide & just barely sand the corners smooth so they don't mark the balsa.

Lay out all your pieces & if they bow in 2 directions - like rocker & to the right - put the heavier curve up for rocker, & line up all the secondary curves off to the same side. They'll match up better like that.

Clamp the first two pieces to be jointed together with 4, 5, or more small screw or c clamps. Very loose clamping - you're just holding them together, not squeezing. You want big enough throats that the clamp pads are centered vertically on the wood. You want the backbone of the clamp above the wood by 1/4" or more. Do not use less than 4.

Start to recut the split between the two pieces. You'll take out a minimum of material - only the saw's kerf width - but the joint will be exactly matched, even if you wander the wood through the saw or if the wood isn't straight. Don't clean up the edges with a planer or jointer - you even want the saw marks to match. Every time you pass a clamp with the saw, tap in a shim right behind the clamp to maintain your new margin.

Work your way across the board, doing pairs at a time - like cut the joint between 1 & 2 first, 2 & 3 second, 3 & 4 third, etc. You can adjust the fence for each piece so you lose even less wood.

You may need to add a low fence to your existing fence, so there's clearance for the clamps. A piece of hardwood clamped onto the front edge (the side you work from) of the table does the trick for me - just set your fence to the width of your workpiece + the width of your low fence. With 8" of balsa sliding across the table, you're not going to tilt or twist it, so you don't need a big tall fence anyway, just a straightedge/blade-distance-setting.

If any of this is unclear, ask questions. Its a great way to make joints without losing a lot of time or wood...

Change out the blade and the belt. Old drive belts get brittle & slick and can act like more of a clutch than you want them to.

The beauty of cutting both sides of the joint in one pass is that if you do get wobbles or curves or saw marks, they'll match and glue up true anyway.

I highly recommend that you only glue up one plank at a time (that is, two planks but only doing one glue line). This is a critical process and you want to be sure that everything goes right (i.e, is lined up properly). If you glue more than one at a time you are probably asking for trouble. The planks may not be lined up right or they may slip all while you are working against the clock (i.e., your glue or epoxy is setting up). ONE AT A TIME ENSURES MAXIMUM QUALITY CONTROL.

I have used both epoxy and good ol' Elmer's wood glue. The advantages of epoxy are: very strong and waterproof plus you don't have to worry about your glues lines being "precise". In fact, small gaps between planks filled with epoxy are even stronger (if somewhat unsightly) whereas gaps filled with wood glue are weak. Disadvantages: Epoxy cost more and will present certain 'issues' when shaping the board since it is substantially harder than the balsa itself (akin to dealing with the balsa stringer when shaping a PU foam board, only imagine having several stringers to have to deal with!).

Wood glue is cheaper and easier to use than epoxy since you don't have to worry about mixing anything together, just squeeze it right out of the bottle (also easier to clean up). But your glue lines do need to be as thin as possible to ensure a strong joint. Shaping will not be as difficult (as compared with epoxy) provided your glue lines are thin. If they are too thick or wide then the glue will be brittle and may even break up into little chunks that will embed themselves in the board's surface. Very annoying to say the least!

You can get wood glues that are waterproof but they cost more. I don't really think they are worth the cost on that basis alone since (theoretically) the glue lines will never be exposed to water (since the board will be glassed) and any such exposure should be very, very minimal at worst (dings) and limited to the immediate area of damage.

Anyway glad you found my thread to be of help and/or inspiration. Sorry I'm still not in the San Diego area to help you out (I moved to Samoa back in September 2005). Unfortunately I haven't been able to build any boards since I left San Diego for Samoa. However, Samoa does have some timber species (not balsa) that may prove useable and this is something I would like to investigate further (I brought most of the hand tools I would need for making boards with me, I just haven't been able to seriously pursue this project yet).

I theorized that that probably is a Mac compatibility issue, although if you're talking about leaving the program on while you do other things, and you come back to a gray screen, that happens to me all the time. YOu can usually wait for it to kick back on after a minute or two or threee....it used to crash on me sometimes, but not since I figured out that I was shortening boards up and slice lines were dropping off the ends, which would somehow corrupt the file to where the PDF wouldn't work and crash the software too. Hope that helps (you delete the slice lines that will be dropped beforehand)

Also, I've never figure out how to view a brd file here--I always just make the PDF to show it here.

I originally thought you were doing a chambered twin keel fish and I thought "oh that'll be good (with low rockers)--the weight of the wood will be great for projection and it'll be fun to cruise smaller stuff with weak spots and blaze points," but the performance thruster/quad shortboard thing in semi-solid balsa seems like a missed application--that's a compsand project. Anyone else?

(OH and that's a very cute little smile you posted back there)

Well. Here's the deal. A retro fish would be shorter, but have straighter (not as toed in), bigger (longer base) fins, and straighter rails, so it's not at all the same thing as taking the center out of a thruster. They cruise and carve, and while you can design them and ride them so short that end up with a skateboard, which is a ride you'd have to get used to, a 6 footer with twin keels that aren't toed in more than 1/4" wouldn't be squirrelly, would draw longer curves in turns and be forgiving in how you surf it more off your front foot.

I understand what made you go the way you did. But I would want you to get a board out of it all that you'll like, which I would wager isn't a 17lb shortboard thruster. I think that weight estimate you did is probably very close to the final weight, so it's up to you.

Quote:

I did some searching and found a thread with a post from thefishexperiment. The design that he posted looks nice to me. I took the two images from the website and imported them into APS 3000. I then modified the design a little bit. I first decreased the length from 6'3'' down to 6'2''. Then, I increased the volume by adding to the thickness (2 15/16''). APS 3000 calculated the volume to be just over 43 liters.

Mate,

You should have asked as I already had the file in aps3000 format... that's how I got the template image for my website in the firstplace. For the most important question, what was the volume in beers? :)

-Cam

swied: looking very nice mate. the redwood adds a nice touch.