Building Materials

D Faust

I have heard that a lot of people make their robots using expanded pvc.· I d not have a lot of fancy·equipment and was wondering whether it could be cut easily with hand tools.· Also is plexiglass a good substitute?· I read that ccoping saws can be used with it.· I would like to make a round platform about 8 inches in diameter with some holes for the wheels to protrude through.· Thank You!


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D Faust

Post Edited (D Faust) : 5/6/2007 11:51:46 PM GMT

Forrest

PVC is soft - it's easily cut with hand tools or power tools. Keep the RPM's low to avoid heating up the drill bits

Plexiglass is somewhat tricky to cut, and I've only used power tools to cut it. Plexiglass is somewhat brittle, so you should tape both side of the cut with masking tape and use a fine tooth saw to prevent cracking.

D Faust

Thank You Forrest, I thought that plexiglass might be brittle, but have never encountered PVC until I read about others using it.

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D Faust

Dgswaner

Here is what I use or have used..

Aluminum- Home depot is a good source you can get flat angle tube and square tube. it's a nice medium but it's pretty pricey. I made a 6 legged walker with only a drill and a hacks saw. check out http://www.thinkbotics.com for examples. it's kinda like using a custom erector set.

Plexiglas- you can find it just about anywhere. it's very in expensive and easy to cut, drill or shape. the down side it that it's very brittle. even just drilling a hole can crack it. I would only recommend using it for smaller projects. I have built several Boe Bot sized bots with great success using Plexiglas. if you plan on using it a lot I would recommend getting drills specially sharpened for plastic. Step drills work great on plexi also. Lexan is a lot like plexi but is less brittle.... and more $

PCB fiber board. great stuff hard to come buy. I had the fortune of working for a PCB manufacturer and was able to get a lot of PCB boards that were discarded. most of them had no copper on them. not sure if you have a company near you that would let you "dumpster dive" if you do this watch be cautious as they use a lot of toxic chemicals. use gloves and wash the boards really good before using.

Polyethylene- I found a great local supplier of all sorts of plastic. I said that I want a plastic that is like plexiglass but isn't brittle and that I can drill and bolt things to and polyethylene was what they suggested. it's a great material but it's a little pricey about $10 a Sq. ft.
I was able lathe, drill and bolt to this medium with real ease. It's a lot like PVC but it's not quite as heavy. I have to double check the name. I'll find out for sure and edit the post. the place that I buy plastic from has a lot of scrap Plexi, PVC, and just about any type that they sell for cheaper than normal. I think having scrap is part of that industry and I'm sure you could find a local source. the same supplier sells plexi in 1/8" diameter Rods in increments up to 2" they sell square tube and rod in the same sizes. and also have plexiglas balls. that I use in stead of casters on small projects.

hope that helps. Good luck.

D Faust

That comparison of products is just what I needed because I am new to robot construction, although I have worked with VEX parts.

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D Faust

Kenny Gardner

but it's a little pricey about $10 a Sq. ft.

Wow, that's a lot. Where are you buying it?

Budget Robotics sells it for $5.00 a square foot and McMaster has some 24" x 24" for around $22.

Kenny

D Faust

What thickness of expanded PVC would I need to make an 8" diameter base that won't snap easily? 1/4"? What about the aluminum thickness? Sorry to ask so many questions, but I am new to this.

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D Faust

dbc1218

Check out www.budgetrobotics.com they have expanded PVC sheet and pre-made bases. You can get a 8" diameter 1/4" thick base with some predrilled holes for $8.50. They have some other nice stuff for building as well, brackets and what not. I've never got anything from them but it looks like nice stuff for decent prices.

D Faust

Yes I had seen budget robotics mentioned in many other posts and checked the site out. Do you think 1/4" is the proper thickness?

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D Faust

Dgswaner

well I need to check the actual material, and the pieces I bought at $10 a sq.ft were cut to size and 3/8" I think what I got was a little closer to HDPE then PE. but as soon as I hit submit I'm definitely checking out budget robotics...... my source a local sign shop.

Beau Schwabe

D faust,

Years ago I worked for a prosthetic facility in the robotics research and development department. The general rule of thumb was if we couldn't cut a 12 square out of the material then it was considered trash.
The thing is, it would generally cost more to recycle the plastic vs. just throwing it away. I would be willing to bet, if you made friends with your local prosthetic facility, they would probably·give you the material for FREE.

There were two main materials that we used....

Dy-Clear (similar to Plexiglas, but not as brittle... much easier to work with)
Poly Propylene (opaque plastic milk carton material)

...both materials ranged in thickness from 1/8th of an inch to 5/8ths of an inch. (most common used was 1/4 inch)

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Beau Schwabe

IC Layout Engineer
Parallax, Inc.