Plastics preferences

[mk460]

I'm considering getting a shopbot and was wondering what plastic material you folks prefer? advantages/disadvantages?

The material I need will be around .375" thick fro some small endpanels for a piece of electronics equipment.

ABS, Kydex, Expanded PVC foam and a Urethane sign board (precision board) are the ones I'm familiar with.

The precision board is very dusty.

I hear the PVC foam may be the way to go?

THANKS kindly for any help.

[Gary Campbell]

Mike...
I like the PVC type 1 solid. Its stronger, glues very well and holds screws much better than the foam. Heavier and more $ too.
Gary

[mk460]

Ok Gary, I'll have to run that by my plastics guy but I think I have an idea what you're talking about.

My major dillema is that my small pieces (7" x 2")
will need to be painted.

The foam takes paint very well from what I understand and believe it or not, abs and kydex also do well with my 2 part Polane finish that I use.

Are you saying the solid PVC 1 will just machine nicer? Good crisp edges etc?

Are you familiar with that urethane board I mentioned? -- man that stuff creates a lot of dust.

[mk460]

Gary --
Also, do you know a source for some smaller pieces of the type1 you mentioned? 12x12 12x24 etc

Often times I use Mcmaster Carr or US plastics so I don't have to buy a full sheet, just for material to play with.

[Gary Campbell]

Mike..
The PVC foam, is white and we get it from the sign supply, they call it "Signfoam". The Urethane foam, they call "HDU" we get it mostly in 15# density, and yes it is dusty.

The PVC solid machines well and it is the same density on the interior as the face. Type 1 white is the same material that PVC pipes are made from.

I get it here from Piedmont plactics, but USP & McMaster should have it. look for PVC type 1 (gray or white)
Gary

[mk460]

Yeah, McMaster had it (they have everything) -- I just ordered some.

One other question, have you had any experience trying to paint the type 1 PVC by chance?

Thanks.

[Gary Campbell]

Mike...
I have painted it with enamels (rustoleum hardware store type), lacquer and post cat lacquers, all with very good results.

I used to glue it with the regular plumbing type pvc cement, but have switched to Devcon Plastic Welder (15 min) its a Methacrylate 2 part that really bites into most plactics. It works well to glue the pvc to acrylics and even aluminum.
Gary

[mk460]

Fantastic -- thanks.

I really may start thinking seriously about a shopbot buddy.

I need to do some rounded corners or I'd do it all with conventional tools.