The Differences and Similiarities of PVC, PVCU, and UPVC

[@DougSkaalrud]

We usually use PVCI fittings and pipe in our shop but every now and then the vendor messes up and gives us PVCU fittings and pipe instead. The two materials are both "hard" so it's too simple to say if a part is hard it's automatically PVC. High density polyethylene in depth can sound just like PCV. There are two manufacturers making PVC parts in the U.S. and while they may look the same the socket depths are different and with one brand you can trust that the marks on the parting lines that you use to calculate pipe lengths are actually the middle and you can trust your measurements. On the other brand you first have to locate the halfway point and mark it before you can proceed to calculating the pipe length you need and that really slows you down when you're trying to glue up pipe runs.

[@Fragmentofbone]

I have a PVC-U pipe that I need to glue up/bond. I have never felt more confused about how I should proceed. Will regular PVC procedures ( purple + cement ) also work on PVC-U? Or do I need a special glue, just for PVC-U? And if yes, do I need to Prime PVC-U , or it doesn't require Primer? Someone told me I should use MEK + PVC-U cement. But does that mean I don't have to clean it? How many things do I need? Is there a cleaner just for PVC-U? I have no idea what I am doing.

[@PlasticPipeShopTV]

Hi there, if it is a rigid pipe that you have and it is made from PVC then it's the same stuff whether it has PVC, PVCU or UPVC marked on it and so it should all be treated in the same way. In some parts of the world a purple primer / cleaner is used so it can be clearly seen, after the joint is made, that the correct procedure was followed. In other parts of the world a clear primer / cleaner is used. Primers/cleaners are solvents that are used to remove contaminants on the surface of the plastic, which may be from the manufacturing process or accumulated during storage, transit etc. It also serves to provide a better keyed surface for the glue/cement to "melt" into. Some manufacturers have their own formulae for the primer/cleaner, one of which is MEK, but they all do the same job. The glue is actually a thick solvent compound which works by melting the two surfaces together, which is why the process is called "solvent welding". There are many different manufacturers of solvent cement, calling it many different things but like the cleaner, it all basically just the same job. Some are thicker or thinner than others, and some are thixotropic, which means although they may appear quite thick, when under pressure (Ie pushed together as a joint) they become thinner which enables them to fill any voids in the joint. The only other processes you need to follow are : 1. ensuring that the end of the pipe is chamfered, as otherwise it can act as a knife edge as it goes into the socket and push all the glue in front of it 2. If it is old, reused or excessively dirty, then emery cloth should be used on it before the cleaner. 3. That when pushed together, the pipe and socket are not twisted, as this can potentially lead to more void spaces in the joint. If you need to adjust the pipe once it's in the socket, do it immediately after it has been fully pushed in, and then hold it in a position for a few seconds.

[@steveknight4291]

THANKYOU