Lets talk plastics. The outfit I want to order from has
High, and low density polyethyene,
Natural Nylon 6/6,
Cast Nylon 6 with Molybdenum Disulphide,
All of these are in square bar form. My only need is a nice finish. The cast is black, and that would be prefered, but not a deal breaker.
Gary

All of these are very, very easy to machine. HDPE is the cheapest, the MD Nylon (Nylatron GS) is more expensive. HDPE machines with a great finish (so does the MD Nylon) but is just a hair more difficult to 'deburr' than the Nylon. Nylons will absorb moisture and so will the HDPE - dimensional stability and UV protection are some of the properties to consider. The MD Nylon is the most stable on the list but is far more expensive.

I have attached a cost comparison between numerous plastics and other materials - this was done a few months ago when I was searching for an inexpensive prototyping/proofing material. THis file may have more info than you need, but here it is.

You may want to look at the Acetals. Very pricey, though.

Scott

Scott,
Thanks, I will keep that for future ref. One of my guys remided me that MSC carries Nylon... Duuuu.
And its in black. They offer a Nylon6/6 and a 6/6 that is MDS filled. They claim better machining a increased lubricity. But its is cheaper?? Sounds like the way to go. Normaly better is not cheaper :D
Gary

also for materail Mcmaster Carr has materail property and user info on web site and carries all above

also for materail Mcmaster Carr has materail property and user info on web site and carries all above


You can check out www.use-enco.com as well. ;)

Thanks for the replies,
I am going with the nylon. As far as properties go..I just needed a step above wet newspaper..Just really need a nice finish.
Gary