Machining PVC

[Rogue Sub]

With regards to machining PVC. What machines better Type I, Type II, or CPVC.

Trying to order some stock to machine on the lathe from mc masters

[Guest]

Didn't know there were different

Didn't know there were different types. I just get offcuts, which are cheap. It always machines well, it's soft and easy to cut, just don't try and work too fast otherwise it can melt and stick to the toolpiece, and leads to a lousy finish.

[emspaul]

Have you tried Acrylic or

Have you tried Acrylic or Derlin?
They both machine real nice.
How big of a piece do you need ?
What are you making?
Paul

http://www.homeportmodels.com/

[Rogue Sub]

I want to make some

I want to make some end caps for a 4" wtc I am creating. I was looking at using 4" round clear PVC to do so. DO you think acrylic would be ok or do you think it would just crack?
I do have deralin but I have found that silicone doesnt adhere to it very well.

[skip asay]

Go with acrylic if you're

Go with acrylic if you're concerned about silicone adhering. It won't stick to PVC all that well, either.

With that said, I've used PVC for end caps but I've threaded the BHS seals so I'm not using silicone.

And, like Andy said, PVC machines very nicely.

Skip Asay

[Guest]

Have you considered using an

Have you considered using an adhesive like sikaflex 552 instead of silicone. Much stronger and bonds to plastics very well indeed.

They use it for sticking portholes into fullsize ships.

Andy

[Guest]

All the plastics listed will

All the plastics listed will work well. Use what you can get hold of easily and afford.

Delrin(acetal) has a higher melting point than PVC, so it stays more dimensionally stable when machining, therefore it's superior for high tolerance components, and is a good bearing material. It's much more expensive however, and for the vast majority of submarine components, the higher accuarcy isn't required. End caps aren't a high tolerance component generally- I find the tolerance of extruded tubing to be all over the place, so you just make the endcaps to fit.

Acrylic is a different animal to PVC or Delrin. For a start it's a thermoset plastic as opposed to a thermoplastic. This makes it more brittle(but more rigid), and the quality can vary enormously between brands. You need to take care when cutting and drilling acrylic to avoid building thermal stress in the material, in short use fine cutting blades and take light cuts. A bit of water when drilling, perhaps mixed with a little bit of washing up liquid helps cool the plastic and aid the cutting process.

Polycarboante (Lexan) is a good material. Machines similar to Delrin, but is gin clear and a bit cheaper.

[scott t]

Would there be enough strength

Would there be enough strength in PVC to machine a
bayonet style connecting ring?

[Guest]

Yes, but I'd make the

Yes, but I'd make the sections thicker than the aluminium ones.

Andy

[tommydeen]

PVC is good I would

PVC is good I would not use Acrylic. a friend turned out a nice part on the
lathe during one of our saturday work sessions and after he was done
he was cleaning it with some acholhal and it cracked and fell apart in front of his eyes!! kinda cool but an hour of work down the drain

[Rogue Sub]

pvc it is!!!!

pvc it is!!!!