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Unread 15-12-2004, 16:55
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ahecht ahecht is offline
'Luzer'
AKA: Zan
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Re: Has any team or anybody made a 80% - 100% lexan bot?

Quote:
Originally Posted by Gary Dillard
2) We started using Lexan when it was an unlimited allowable material because it made very nice assemblies. It is easy to machine and it makes nice square corner joint assemblies - we drill pilot holes through the edges using 3/8 inch thick Lexan and use self tapping drywall screws. You need to use Lithium grease or the screws will shear while torquing (use the low torque setting on your cordless drill when installing them), and don't use locktite because it heats up, expands and cracks/delaminates the lexan.
While that would probably work quite well, I would highly recommend that anyone using lexan first glue the pieces together using an unthickened methylene chloride solvent glue. You can get this from any plastics supplier. It is applied using an applicator bottle that has a needle tip and uses capillary action to flow between the pieces of lexan. The solvent breaks down the plastic's surface, allowing the pieces to chemically weld themselves together. Edge preparation prior to glue application is of utmost importance. Your final seam will never be better than your beginning edge, so you may need to use a mill to make a flat edge if you are gluing a cut side.

Once the edges are glued, you can drill and tap them (or use self tapping screws if you are feeling lucky), and they will never come apart.
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Zan Hecht

Scorekeeper: '05 Championship DaVinci Field/'10 WPI Regional
Co-Founder: WPI-EBOT Educational Robotics Program
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