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joncynb
Dry-fitting PVC Pipe

Is there any product you can put on PVC pipe during dry-fitting to allow tighter and easier assembly and disassembly that will not harm the final glueing? Too often it is hard to get an accurate measurement during dry-fitting if the pieces don't fit entirely in place, but if they do it is then very difficult to get them appart for final glueing. I have asked several plumbers and home improvement stores for advice, but no one seems to know of any appropriate product. Thanks for any information anyone can provide.

johnjh2o
Re: Dry-fitting PVC Pipe

The simple answer is no. Measure twice, cut once, then use primer then glue.

John

rdesigns
Re: Dry-fitting PVC Pipe

Learn to do what plumbers are taught: measure from centerline to centerline of whatever fittings you're working with. This C-C measurement is the gross length of pipe, so you then subtract the "fitting allowance" for each fitting.

The centerline of a 90-degree bend, for example,is where the two centerlines of the pipes would meet within the body of the 90. The fitting allowance is the distance from that point to the point where the cut end of the pipe would be located in the socket of the fitting. On a 3" PVC drainage 90, this is about 3".

So, if the C-C measurement between two 90's is 25", you would subtract the two fitting allowances of 3" each for a final cutting measurement of 19"

As an aid to rotating the fittings after the glue has been applied, always scrape a small chamfer on the cut end of the pipe--this is because if you leave the cut end as comes from the saw or pipe cutter, the sharp corner of the pipe scrapes and pushes the glue ahead of itself and the joint thereby loses a lot of the lubricating effect that the glue provides just before it begins to set up.

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