Wood vs Aluminum

[Mike Starke]

Originally Posted by Zoheb N

that if your robot does get rammed alot during competition you have the ability to beat it back into shape where as if you have it made out of wood it will chip away and become irreplaceable

^Totally agreed.
I have to lean towards trusting welds more than trusting screws or nails, when it comes to either assembling the lower flame, or when it comes to attaching upper frame pieces. Also, if you made it so the two frames would way the same, that would be some awfully thin and unstable wood. 3/4 inch square aluminum is plenty strong for most frames, and is very light.

[Mike Norton]

I have used wood on 10 of the 12 robots built. The right wood works great. Due to the high impact it will take without breaking. Team 61 robot has been know to hit a lot of robots. But the robot frame has never failed. A wood frame works great to start from due to you can place any part on it with out a lot of work. Just pick a spot and put it there. where the Aluminum you need to do a little more work to make it fit.


Wood and the parts it take to put on different devices are cheap. The hardest thing with wood is knowing how to use it in the best way to get the most from it.

[Tom Bottiglieri]

This is my first year NOT working with wood for a drive base, and I must say I don't really have a favorite.

Wood is, for the most part, easier to work with. With little to no resources you can cook up a pretty solid base in less than a day. Electronics mount up nicely to it, and you can even give it a slick automotive paint job. Beyond that, with the proper reinforcement you can slam the thing into walls all day and not have to worry about it bending or breaking.

Aluminum is a bit lighter, and more customizable. You can get some pretty unique shapes and work motor mounts directly into your parts.

I don't really see a big difference in terms of strength (for the purpose of a drive base) between wood and aluminum. Wood has the tendency to gouge, which isnt all that pretty, but for the most part it holds up quite well.

So, I guess its all a matter of personal preference and experience. YMTC.

[travis]

Here are some useful properties of Birch (home depot grade plywood material, aircraft grade is void free with superior propeties at about 3X the cost) and 6061-T6 aluminum (all in KSI):

aluminum wood
tensile load at failure 45 10
modulus of elesticity 10,000 2,000

Here is that same table adjusted for density:

tensile load at failure 16.7 16.7 (ahhh perfection)
modulus of elesticity 3703 3333

Price of a clamp = $5, price of a square wave TIG machine = $1500. Home depot grade wood glue can acheive 80% parent material strength with much less skill then welding, and you don't have to heat treat glue joints for full parent properties. Anyone want to race me to install a new limit switch with 2 wood screws vs tapping holes? How about hand jigsawing 10 linear feet? With a rookie team (3rd in a row for me), 6 weeks, and no money, I got wood on the brain.

[MrForbes]

Originally Posted by travis

Price of a clamp = $5

Nice comparison!

although you can use a $1.50 clamp to hold an aluminum bracket on to an aluminum structural part too, if you design it right....no welding needed.

[John Gutmann]

Originally Posted by squirrel

Nice comparison!

although you can use a $1.50 clamp to hold an aluminum bracket on to an aluminum structural part too, if you design it right....no welding needed.

Well then you can use a 1 cent woodscrew to hold the wood inplace! Beat that!

[MrForbes]

Originally Posted by sparksandtabs

Well then you can use a 1 cent woodscrew to hold the wood inplace! Beat that!

No need to beat that, I was just trying to make the point that you can build a robot with aluminum with only hand tools, if you really want to. There is no need for a TIG welder.