Outside wall has water pipe that evidently has to do with the tub faucet in bathroom. Copper pipe is connected with a copper snap on fitting recommended
By the plumbing supply house, it is holding great, but the pvc elbow on one end blows the pvc pipe back out and or on the other end has coupling into elbow it will blow the pvc pipe out. I used a pvc purple primer with pvc clear glue, let it sit for 15 or so minutes and it just blew on both ends this time. When the pipe is blowing water the faucet for bathtub works fine, when the pipe is not blowing water out and holding the way it should be the bathtub faucet does not have hot or cold water , nothing. I do not understand

Your are using PVC purple primer and PVC adhesive but are you using PVC pipe?
What color is the pipe?
Is it white of off white (beige).

PVC is not normally used for interior plumbing, can not be used for hot. For this CPVC is used.

Show pic of what you are doing.

Depending on the pressure, you may need to keep pressure off for 2-3 hours. "Snap " fitting -Gator or shark bite? Don't think they fit PVC.

What is the PSI house pressure? Is there a PRV valve installed/ (see image) Just to be sure are you saying the elbo blew out both glue joints? Back to you. Tom