Many folks do not understand about how the various plastic pipes are joined. There are 3 basic kinds of plastic pipe; ABS, PVC, and CPVC. They are chemically different. That much is easily understood. The problem comes in the fact that what we all commonly call pipe "glue" or "cement" is neither of these. They are solvents that melt the top surfaces of the pipe and fitting briefly. When the two surfaces are joined, the liquid surfaces combine into what is actually a chemical weld. So, it's not a matter of bonding, strength, or sticking. Each type of pipe has its own solvent, so the answer to your question is, No, you can't join different types of plastic pipes, except by using appropriate adapters. Not known what you are doing and why you would need to join CPVC to PVC, it's hard to advise you on what you may need to do. A couple of problems with PVC and CPVC pertain to why you are mixing media and size incompatibility. In other words, 3/4 PVC is not the same size as 3/4 CPVC.