Thunderbolt tadpole in wood

Really a shame to hear that Zap, that was one beautiful trike! :(

I guess that is one of the things about wood versus metal, there really isn't any bending out of shape and putting it back into shape, but I can see where laminated stuff is really strong.
 
@whiteblade & zap: are those the same trike? They look very similar! Do you have more / larger pics you could send me?

@zap: Your trike is very similar to the Thunderbolt MK1 that mine was intially based on. Where did yours snap? Can you show any photos of the breakpoint? I'll need to be careful to reinforce that location with extra metal plates. :)

Today I'm going to design the crossmembers and the interlocking piece that goes below them, as well as a gusset connecting the two from above, which will be mitered into the front frame's web gusset from the plans. It might be overkill but this is an area that I need to be as strong as possible. :)
 
Sorry guys, the way I worded that made it seem like it was my trike... it's not.
Mine was a SWB 2 wheeler made out of 13 ply baltic.

Kris I noticed the similarity with the one whiteblade posted also. Looks like the same design but definitely different wood.
The one from whiteblade looks like soft wood plywood whereas the one I linked is mahogany.
 
Kris,
Consider using sitka spruce. In the old days a ships mast was made from this wood. It provides the most strength for the weight. It grows in Alaska. That causes a very tight grain pattern. It is also used on the face of guitars and violins and in pianos for their sound boards. It is expensive if you can get it but you don't need too much. What kind of woodwork did you do in the past? And could you elaborate about your workshop and tools.

Thanks and good luck,
ebent
 
Thanks for the clarification Zap! :)

Spruce could be a good choice. There are always free pianos on craigslist that I could use for building materials. With lamination however, hardwoods would not be a very good option. I'd probably use birch, which is flexible and strong while also not terribly heavy. Speaking of spruce, birch was used to build the "Spruce Goose" :)
 
The picture's i have posted where one's i got of the internet a few years ago.Can not find the website i found them on.

Have you thought about GRPing your wooden frame for extra strength, depending on how many layers you would still see the wood.

Just an idea anyway.
 
If I was going use a hardwood I would try to find some straight grained, quartered white ash. Ash is also used for masts as well as baseball bats at the pro level. It is much heavier than sitka spruce, like any other hardwood.

ebent
 
@ebent: Sorry I missed the part of your post earlier where you asked about the woodworking. All of my past woodworking experience is in theatre set design and construction in both high school and college a very long time ago, unless you want to count my pinewood derby and whittling days in Cub Scouts and Boy Scouts. I'm good at figuring out how to make platforms that'll hold weight, and walls that won't fall over but have very little actual substance to them. In theatre though, most of the sets are bolted together rather than epoxied. They are made so that they can be disassembled and rearranged with very little effort, and permanent adhesives get in the way of that. Therefore I have almost no experience with that sort of thing. I went for bolting 2x4s because it's what I know. :)

As for tools I've got the basic hand tools, as well as a nice jigsaw and a generic drill press. Not enough to impress any serious woodworker, but it's slowly growing. :) Next addition will be a wood rasp. :)

@whiteblade: What's GRP?

Edit: Wikipedia to the rescue! No, I won't be using any fiberglass. I'd like to keep all artificial materials to a minimum, I'd rather not have the broken remains of this thing discovered by some future civilization millenia from now because it's incapable of biodegrading. :) Some elements of the vehicle will inevitably need to be made from such things, of course.

Edit again: As for the hardwoods, the ideal characteristics if I'm bending and laminating layers of thin wood (for the final version) will be flexibility, strength, and weight. Any tradeoffs will by necessarily be biased in favor of flexibility or the bending will be difficult, after that strength, or there's no point in bending in the first place, and lastly weight, which has more to do with efficiency than with ability to last through the punishments of road driving. :)
 
I just did some more googling for electric trikes, this one looks really interesting and is very similar to what I initially had in mind! http://www.coronn.com/poormansecologicalvehicle/
 
The joints you show in the 2x4 mock up won't be strong enough, even in hardwood. You'll need to do something involving laminated wood like the bike in those pics a a page back or so. The bike in the avatar pic is much harder to do, involving lots of steam bending to create the curved pieces.

Get some good marine grade plywood, and cut pieces roughly the shape you need for the entire frame. Then glue them together with a good wood glue till you have about 2" thick piece in the rough shape. Then start jigsawing the whole thing closer to the line of the final cut, sanding down to the actual line in the end.
Looking down from the top, you'd see all the layers of the lamiations, and from the side you could cut the piece into any fancy shape you want.

Experiment first with cheap CDX ply to get the laminating technique down.

To do the lamiating, Ideally you'd have tons of clamps. But you can do a lot with just a few clamps, and screws. Apply the glue and clamp. Then countersink holes with a drill, and put in screws. Remove the clamp, move down a bit, and repeat. When you are done, the screws are clamping the job till it dries. Tightbond 2 water resistant wood glue should be ok for the laminating. Later the whole thing will be well varnished to keep moisture out of the ply.

BTW, I was a house carpenter for 25 years, but not that much of a cabinetmaker or boat builder. But this method should work fine even though I haven't actually built much more than a few table tops using laminating techiques.

Man this thread is getting me going! Now I want to start glueing up some wood myself! Gotta retire so I have time for more fun projects.
 
First I want to ask anyone in the Portland area, where is a good place to get 1/8" aluminum sheet?

@dogman: Thanks for the very informative post, I'll have to break this into smaller chunks to respond. :)

dogman said:
The joints you show in the 2x4 mock up won't be strong enough, even in hardwood...
Click to expand...

I came to this conclusion while drafting the crossmembers on paper. I drew every method I could think of to join them together and only one of them works: An insanely long bolt through the entire horizontal length of the base of the two halves to hold them together, along with a ridiculous number of reinforcing gussets at every possible angle. The solution is simple: Use plywood and cut out the basic shape of both crossmembers at one piece rather than two. 2x4s should be strong enough for the axial frame of the prototype, but the crossmembers will have too much stress on them to use dimensional lumber.

dogman said:
Get some good marine grade plywood... Experiment first with cheap CDX ply to get the laminating technique down...
Click to expand...

This has been the plan from the beginning, dimensional lumber is simply easier to get for free. :D The final version will be a combination of marine ply and thin sheets of birch bent and then laminated together with marine epoxy, as seen here: http://www.borisbeaulant.com/

dogman said:
Tightbond 2 water resistant wood glue should be ok for the laminating...
Click to expand...

That was going to be my question today! :D "What type of inexpensive adhesive could I use for the prototype" I'll definitely look this one up locally!

dogman said:
Gotta retire so I have time for more fun projects.
Click to expand...

Or in my case, just be hopelessly unemployed long-term! >.< Once I finally find a job I won't be able to devote nearly as much time to this project.
 
"This has been the plan from the beginning, dimensional lumber is simply easier to get for free. The final version will be a combination of marine ply and thin sheets of birch bent and then laminated together with marine epoxy, as seen here: http://www.borisbeaulant.com/"


That trike is simply art! It's gorgeous!
otherDoc
 
tightbond II has been my glue of choice until tightbond III came along. It provides more open time and is more impervious to water. Open time in laminations can be very valuable. It is more money but not a big difference and worth it. Especially for your application.

Another consideration vs plywood could be to rip some sitka spruce about an eight thick as wide as you need and laminate that. You can create the benefits of plywood by adjusting each layer so the grains cross. 90 degrees is not important. The grains could be say 30 degrees and that would allow creativity in the shape as well as adding strength. The 2 big benefits would be lighter and stronger. A wood made trike needs to be light and strong.

ebent
 
The other thing I was thinking would be to take your choice of wood, and rip into thin strips. Then steam em, then laminate em into a curved mold. Lotsa work making the jigs, but the result would be really gorgeous bent pieces of laminated lumber.

Diamond plate 1/8 aluminum sheet is fairly common. So are aluminum road signs. :twisted:

I hadn't noticed tightbond 3, nowdays my job is house maintenance, so I'm buying paint, roofing tar, etc. The custom furniture buisness was 15 years ago.
 
With a lamination process no steaming would be required. Just lay out your shape in the glue up process. Use one plane for your most radical shapes. On the other planes, if necessary, carve out your needs. Such as a notch, a bore or some sort of joinery.

If you don't have the equipment to rip the spruce acurately, then pay someone to mill the blanks. A modest amount of work. If the beginings are true you have a better shot at sucess. Avoid quick and lean towards accurate and true. Perhaps a cad drawing made by someone who knows how would be very valuable.

ebent
 
The way my uncle explained it, thin sheets won't need steam at all, warm water will suffice. The jig we designed is adjustable and reusable for any design I could desire. In any event I need a working prototype before I can even consider types of wood or techniques for bending. :D Until then I'm working with free materials scavenged from Craigslist. ;)

Edit: I figured out a solution to my dimensional lumber woes. The reason I didn't think it would work with 2x4 crossmembers was that I'd end up with a butt joint in the middle and they would eventually work loose. A little too much weight and oops there goes a front wheel. The solution is a hook scarph used in boat building. The wood holds itself in place and will not work loose. As long as the wood itself does not split (not an issue for this prototype as it will never carry much weight, go very fast, or be under much stress compared to the final version) it should be fine. :)

hookscarph.jpg
 
KrisWood said:
The way my uncle explained it, thin sheets won't need steam at all, warm water will suffice.
Click to expand...
That was how I made the first seat for CrazyBike2, with thin plywood soaked in a hot shower/bathtub, screwed to a pair of thicker plywood "keels" while wet. I was impatient though and did not soak it long enough, so it cracked at the extreme bend of the seat-to-back curve. Fortunately that didn't matter as much as I thought it might, and it served well enough until I broke the keels themselves. ;)
 
I made a 3D mockup of how the joining of the two crossmembers will look. Since these will be passing through the bottom of the front tube, and have a lower gusset reinforcing them from below, I think it should be sufficiently strong:

crossmembers.jpg
 
My guess is the mock up is easier then real life. How do you think you will be able to execute that joint? Even if it was perfect it would still be a point of weakness. On one plane you can make any shape by creating a home made plywood. Make the lamination bigger than disired to be milled to the precise shape. With your skill level and minimal amount of tools it would be easier anyway. If you do scarf the joint it will require mechanical fastners. A lot. Such as bolts or screws or something. Scarfs are generally used when the length of stock required is impossible or not available.

When making the "plywood" you can piece it together. Just minimize voids. It is OK to piece it together because each layer the grains cross. That gives the strength.

ebent
 
In case it hasn't been mentioned in this thread, plywood sandwiched with aluminum sheet is very strong. ES member Bubba ("dontsendbubbamail") uses the technique extensively.
 
You could always try a plywood box frame, too - you don't have to make the bits of wood look like steel tubes. The tricky bit to achieve with that technique would be the vertical thinness required under the seat...
 
Sounds like adding aluminum would add strength. How does he marry the 2 together? Bolts? Will epoxy bond? Is the weight mesurably different? Including bolts if necessary.

ebent
 
Wow that's pretty cool. I'm surprised by how thin that aluminum looks. It can't be more than 1mm thick. The thread says he used JB Weld and Elmer's wood glue (the regular yellow stuff) but doesn't elaborate on how it's used.
 
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