Giant Mech (From Comic-Con)

Austin Martin

Senior in high school trying to make one as an engineering student plus or minus a few changes, where did you source the parts from?

Chris Ellerby

Hi Austin,

Where you source the materials will depend on where you live, and what specific materials you are looking to obtain.  In the case of the giant mech, it contained fabricated pieces, vacuum formed plastic, cast pieces, etc.

I'm happy to help you find the right materials and source a location to purchase them if you can provide some information about where you want to start.

/Chris

Austin Martin

I'm in Indianapolis and I'm thinking on starting with the skeletal frame.  I didn't know where you guys got your metal or your joints I'm looking at Igus right now for a few ball and socket joints but they're plasticky and look pretty breakable under any sort of weight.  I've designed and built a system that'll let me manipulate a pair of super sized hands with my hands but but I need the arms to put 'em on!  Thanks for getting back to me!

Chris Ellerby

I would try and avoid plastic for any load bearing structures, as it's prone to snap, warp, or flex.  In some cases you can get by with PVC, but wood, aluminum, or steel are ideal.

/Chris

Cyril Wichers

There's lots of different types of plastic. The products Igus makes aren't exactly made out of your ordinary run of the mill kind (and not particulary cheap either) They make parts for robotics too: http://www.igus.eu/wpck/6076/robolink?C=DE&L=en

Chris Ellerby

That's true, but when you are talking about 15 foot tall creature suits you really don't want anything load bearing to be plastic.  Like anything there are some exceptions, but most common plastics have properties that are not ideal for the task.

With large structures the amount of force on joints, support brackets, long limbs, etc. can be pretty significant.  Especially when you have long moving loads like limbs.

While plastics have a lot of great properties, what plastic you pick should be tailored to the specific application.  You need to consider factors like how much flexibility/rigidity you need so you are not wasting energy moving limbs that are wobbling around, how components will handle heat when stored in a hot vehicle/warehouse, how time and UV exposure may make certain materials brittle and what the expected lifetime of the product is, how much weight can the material handle before failing, how it handles torsion/lateral forces, etc.

Don't get me wrong, plastics are great, and some are down right magical.  But chances are any hobbyist making a giant robot costume will not have access to (or the finances for) the kinds of plastics or composites that could reliably handle the task. 

/Chris

Cyril Wichers

Yes, you're completely right. That's also why I said that the products that might be suited will probably be expensive.