Bridge material question

[koo_04]

I was not sure where to post this exactly, so it can moved by the moderators later.

I would like to know a good place to buy the HDPE. I look places and most are 300+ bucks. I was hoping maybe there is a cheaper place?

[Peter Matteson]

Originally Posted by koo_04

I was not sure where to post this exactly, so it can moved by the moderators later.

I would like to know a good place to buy the HDPE. I look places and most are 300+ bucks. I was hoping maybe there is a cheaper place?

FYI
The bridge surface is lexan not HDPE. The key is HDPE.

[dez250]

Also if you don't know Lexan is a brand name for the material from SABIC. The generic name is polycarbonate which you can get fairly inexpensively for thin sheets.

[Gray Adams]

We bought a sheet from our local plastic supplier for $96.

[Tom I]

Another option for teams with a tighter budget, Lexan (or other brand of polycarb) will mimic the behavior of HDPE pretty closely. The question becomes do you need it to be EXACT? or is CLOSE ENOUGH good enough for what you're doing. I'd say for driver testing, you won't need anything more accurate than Lexan.

[Phyrxes]

Originally Posted by Peter Matteson

FYI
The bridge surface is lexan not HDPE. The key is HDPE.

The offical FIRST field drawings say its HDPE. But in the video tour of the bridge they call it polycarbonate.

For what its worth a 48 inch by 48 inch sheet of 1/16th hdpe is about $20 from McMaster + shipping.

[RufflesRidge]

Originally Posted by Phyrxes

The offical FIRST field drawings say its HDPE. But in the video tour of the bridge they call it polycarbonate.

For what its worth a 48 inch by 48 inch sheet of 1/16th hdpe is about $20 from McMaster + shipping.

The bridge deck is HDPE, that's the colored part. The bridge surface is a sheet of polycarbonate velcroed on top of the deck.

IMO, the important part to recreate is the surface, which is polycarb. This is what will affect driving characteristics the most.

[Phyrxes]

You are right, I got the bridge deck and surface mixed up.

[IceStorm]

Originally Posted by Phyrxes

The offical FIRST field drawings say its HDPE. But in the video tour of the bridge they call it polycarbonate.

For what its worth a 48 inch by 48 inch sheet of 1/16th hdpe is about $20 from McMaster + shipping.

Would you be able to provide the part number at mcmaster? I haven't went looking yet but know that there catalog is quite vast in what they carry.

[Gdeaver]

Watch out for shipping on a full 4 x 8" sheet of polycarb.

[davidrk13]

so im trying to build the seesaw (bridge) and i cant seem to find any plans/blueprints anywhere . can anyone help me out?

[Phyrxes]

Originally Posted by IceStorm

Would you be able to provide the part number at mcmaster? I haven't went looking yet but know that there catalog is quite vast in what they carry.

8619K427 is the part number for the 48 inch by 48 inch by 1/16 of an inch thick smooth sheet in white.

http://www.usfirst.org/sites/default...amDrawings.pdf is the "low cost" (Read: lots of plywood and 2x4's field elements).

[Flimsor]

Originally Posted by davidrk13

so im trying to build the seesaw (bridge) and i cant seem to find any plans/blueprints anywhere . can anyone help me out?

It's all here:

http://www.usfirst.org/roboticsprogr...Field-Drawings

[Alan Anderson]

Originally Posted by davidrk13

so im trying to build the seesaw (bridge) and i cant seem to find any plans/blueprints anywhere . can anyone help me out?

The Competition Manual page on the FIRST web site points to the Field Drawings.

[PhantomPhyxer]

According to FTC Robotics, 2011 -2012 Edition either US Plastics or Mc Master Carr are good sources for this Plastic. We have used TAP Plastic. We have not purchased the plastic for the Bridge yet. We are still building Game pieces. We hope to finish tomorrow. FIRST Team #2643, Mentor