What would be some fun things to build in some spare time? preferably that are cheap and actually useful. I find it fun to make stuff and know that some other people do to.
I’ve built a guitar pickup and speaker that plugs into standard 1/8" jacks.
Anyone have anything fun and easy?
Sorry this sounds cheesy and self centered… :smack:
This is not exactly useful, but it’s a fun thing to play with.
For some values of useful, it’s not very hard to build a dry-ice fog machine. Basically, you’ll need a 55 gallon drum, couple of water heating elements, a fan, a basket, some plastic hose, minor electrical skillz, a way to mount some wheels on it, and maybe weld a drain pipe on the bottom.
Less useful, more fun, is a potato gun. Might want to check local laws before making one.
Beer can pyramid!
Oh, usefull, I recycle.
I’m currently building an underwater case for my Canon 500D camera and a small, portable UAV. Plus a few other minor thins lying around in various states of completion.
If you’re after something less complicated how about making some tensegrity structures? you could make a wicked photo frame or desk lamp. You’ll leave your visitors scratching their heads wondering how the thing doesn’t collapse and just how much free time you have in your hands to waste it like that. 
Here are some fun things I’ve made lately. They aren’t particularly useful, but they did entertain my kids for a surprisingly long amount of time:
An electric motor:
http://home.comcast.net/~sokosfamily/motor.jpg
The square thing at the bottom is a magnet. You can get one like it at Radio Shack (as much as I hate to plug them for anything). You can get the magnet wire there too.
The only trick to building this is that on one side of the wire, use something like a file to strip the insulation off one half of the wire and not the other half. As the coil rotates around, when the part that has the insulation stripped off contacts the paperclip it will make contact and turn the coil into an electromagnet, which will make it flip. If you don’t have the insulation still intact on the opposite side of the wire, the coil will tend to want to stay in the flipped position. By leaving the insulation in place the electromagnet turns off, and momentum will carry the coil around until the part with the stripped insulation again touches the paperclip. Strip the insulation completely off of the wire on the other side of the coil so that it always makes contact with its paperclip.
Here’s another project. It’s a pop pop boat:
http://home.comcast.net/~sokosfamily/poppop.jpg
Here’s a picture of just the motor, which I made by taking a small piece of copper pipe (available at ye ol local hobby shop) and wrapping it around a wooden dowel rod that I had handy (a broom handle would work as well).
http://home.comcast.net/~sokosfamily/popmotor.jpg
Here’s the wikipedia page on pop pop boats if you want to know more:
Science in our schools needs all the help it can get. Maybe one of your projects would be useful as a classroom demonstration.
Im in high school but the projects all suck. I got to do some woodwork for an english project but it wasnt fun by any means.
You could build a little trebuchet.
Telescopes can be fun to make. Not that hard either if you buy the optics already made. You can also hand make the optics, which is nearly an amazing process IMO but that can take anywhere from dozens to hundreds of hours.
Do an internet search for ATM, dobsonians, homemade telscopes, telescope mirror grinding
That should give you plenty to read up on.
You may want to check out Make magazine http://makezine.com/
Brian
Bicycles are fun to build. Like anything else, they can be cheaper or outrageous in price.
I was going to suggest a trebuchet, but I see Rysdad beat me to that.
I just picked up a set of plans for a lightweight canvas-covered kayak, which may start going together in the shop if I ever finish another project or two and make room for this one.
Bomb?
The Spin Art Machine was quite a fun one for me.
What’s the cost for this one?
Thanks,
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AR-15 style rifles are very easy to build and require little in the way of tools. You may, or may not, save a little over buying one off the shelf depending on what configuration you plan on putting together.
I’m about to get the stuff for a pinwheel together. I thought the niece might like to help put one together and watch it spin in the wind.
Why not the whole guitar? That’s a link to the last thread - it has links up to the first one. And if you are feeling really ambitious, you could PM the Doper BigShooter, who has not only built a guitar like I did, but crafted some of the wood parts himself vs. buying ready-made like me…
I used to make individualized Adirondack chairs for family members. Beefed up the structural supports well beyond what you’d find in a store-bought chair and then incorporated different elements that each person had some tie to. For instance for my Dad’s chair I used the wainscotting from my Grandmom’s old dining room for the seat and back planks. For my Mom’s I painted it the same color as her outdoor furniture and set some beautiful tiles from her Mother’s kitchen into the armrest as coasters. For the in-laws they matched the new patio they’d just rebuilt and sported brands burned into the sides that had been historically used on their ranch. For everyone I made the seats narrower or wider, adjusted the height and angle of the seat accordingly. They all still talk about how much they enjoy them and how touched they were to have something made special with just them in mind.