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can you glue pvc to cpvc?

Posted: Thu Aug 21, 2008 1:51 pm
by SilentCyan
a friend of mine thought that since the two have slightly different chemical makeups that it wouldn't be safe to glue them together. i'm pretty sure he's wrong but i figured it would be better to check with you guys rather than take any unnecessary risks.

Posted: Thu Aug 21, 2008 1:59 pm
by SEAKING9006
Yes, you can. End of story.

Posted: Thu Aug 21, 2008 2:29 pm
by SilentCyan
yay! now i don't have to worry about that anymore.

thanks for the quick response

Posted: Thu Aug 21, 2008 3:04 pm
by jimmy101
PVC and CPVC are different chemicals. They will absorb and desorb the solvents in the glue at different rates. In addition, PVC glue contains dissolved PVC and it may not properly fuse with CPVC. CPVC glue contains dissolved CPVC and that may not properly fuse with PVC.

Oatey makes an "all purpose" cement for PVC, CPVC and ABS (here) which they say is suitable for pressurized applications. It contains both PVC and CPVC (from the MSDS sheet).

When in doubt read the cans of glue. I would suspect that regular PVC glue is not suitable for a pressurized system made from CPVC pipe. The converse is probably also true, no CPVC glue on a PVC pipe. The "all purpose" glue should work for PVC-PVC, CPVC-CPVC and PCV-CPVC joints.

If you are gluing up a bunch of pieces of PVC (or CPVC) to make a soccer goal then the glue really doesn't matter. If you are going to pressurize the joint to a hundred PSI or more and then hold it in your hand then I would strongly recommend using the proper glue for the pipe.

When in doubt, version 2; What do building codes say? CPVC glue is usually orange. Would a building inspector red-tag a PVC joint with orange glue on it? Or a CPVC joint with a purple stain, or no stain at all? I suspect that an inspector would red-tag both. I suspect that the "all purpose" glue would not meet US building codes for PWS systems. Therefore, it should not be used on a gun.

Posted: Thu Aug 21, 2008 3:18 pm
by SpudFarm
SEAKING9006 wrote:Yes, you can. End of story.
no it isn't

you should never ever glue two different materials tougether with a glue intended for one of them !

Posted: Thu Aug 21, 2008 3:21 pm
by SEAKING9006
.... Damn. I thought that pipe solvent can handle both of them. Well, the solvent I have can, anyway. I just read the can.

Posted: Thu Aug 21, 2008 3:50 pm
by Sticky_Tape
You CAN with epoxy you don't always need to use the glue that is designed for the pvc and cpvc people sometimes people use epoxy for copper too. END OF STORY

Posted: Thu Aug 21, 2008 4:42 pm
by bigbob12345
Actually its not the end of the story...
Pvc pipe and cpvc pipe have very different o.d's for the givin size. So it would be impossible to glue it together with suffecient strength no matter what glue you use.
End of story...finally

Posted: Thu Aug 21, 2008 4:58 pm
by clide
Or not, CTS CPVC which is most common does have a different OD than SCH40 PVC, but they do make adapters. They also make CPVC in SCH40 and SCH80 although it is much less common.

Posted: Thu Aug 21, 2008 5:38 pm
by potatoflinger
But you could solve the problem in the first place by just using the proper glue for each, and a threaded fitting to connect the pvc and cpvc.

Posted: Thu Aug 21, 2008 7:52 pm
by Maniac
END story here. They do make special adapters for PVC to CPVC because of this
Pvc pipe and cpvc pipe have very different o.d's for the givin size. So it would be impossible to glue it together with suffecient strength no matter what glue you use.
You could also opt for threaded fittings which is what I would do.

BTW: the special adapters are not hard to get they should be with the cpvc stuff and not the pvc.

Posted: Thu Aug 21, 2008 9:56 pm
by SilentCyan
yeah i have one of the adapters because thats all they sell at my local lowes(lucky me the one size they sell was what i needed). i do have the all-purpose glue and solvent so i'm going to go ahead and glue this thing together as soon as i can get my piston working.

Posted: Fri Aug 22, 2008 11:44 am
by jimmy101
SEAKING9006 wrote:.... Damn. I thought that pipe solvent can handle both of them. Well, the solvent I have can, anyway. I just read the can.
The solvent says both CPVC and PVC on it. What does the glue say on it?

There is no "end of story" for this particular question.

Can dissimilar plastics be joined. Yes. The real issue is how you actually do it and will it have the same pressure rating as the code-approved methods.

So, someone saying "yes it can, end of story" is really not being very helpful and may well get somebody hurt.

Posted: Fri Aug 22, 2008 11:52 am
by SpudFarm
here is the end of the story:

you use epoxy to glue it tougether then you set in a few locking screws with epoxy on to seal.