PVC versus polystyrene?

The second part of the question-yes.

The first part- most solvent glues that melt pvc will work, but many that melt styrene will not.

I think MEK works.

The biggest difficulty is glueing the PVC with Styrene. CA, or Epoxy are the best bets. 

PeterPan

Can one use (glue and paint enamels) with pvc like one does with polystyrene?

 

E.G., can I glue a pvc piece to styrene piece and paint both with enamel paint (and nobody would know the difference)?

 

I'd be cautious about painting pvc with solvent paints like enamel or lacquer. Test on a scrap peice first. What can happen is that the solvents could dissolve some of the plasticizer in the pvc and it will end up in the paint film, causing it to dry soft and sticky,  This frequently happens with vinyl tracks on tanks, for example. It may depend on the type of pvc. A pvc pipe may be fine, but a vinyl figure will often be troublesome.

If your test doesn't work out, I'd recommend using an acrylic paint.

I've worked with PVC several times. I have found pipe the right size to do the body of launch vehicles that work with some rockets- truly round compared to oval kit bodies.  No problem with painting- in fact I sometimes use it for trying paint compatibility tests.

I used gel CA for the adhesive, and glued styrene, wood, and sheet aluminum to it.

Thank you all for your responses. It is great news for me.

I want to use PVC tubing, etc, with existing styrene kits to bash together something differently. Some of the ideas shared in "Dioramas You Would Like To Build" thread require kit bashing and more - like using PVC and other bits.

Thanks again.