morbious

Hello
Trying to come up with a technique to cut holes in PVC pipe.

I have a length of 10 inch diameter pvc pipe. I want to attach 8 inch pvc pipe perpendicular to the 10 inch pipe. The 8 inch hole needs to be rabbeted so that the 8 inch pipe does not fall through. I have paper templates that have solved all of the geometries involved in cutting both the hole in the 10 inch pipe and the end of the 8 inch pipe. I will be taping these paper templates on the pipes. I am not sure how to cut the rabbet so its in the proper orientation such that the 8 inch pipe stands straight up.

The wall thickness of the 10 inch pipe is .75 inches and the 8 inch pipe is .625 inches. I wanted the rabbet to be .5 inch deep by .625 inch wide.

Thanks
Mark

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reikimaster

My first question would be...."you can't use a "T"?

I don't have any examples currently, but I've done similar connections in varying sizes of PVC while making prototype musical instruments. Because of the diameters you are using I would suggest to abandon the rabbet.
Cut the hole in the 10" pipe such that the 8" pipe fits into it snuggly.
Shape the end of the 8" pipe so that it fits the profile of the 10" intersection as accurately as possible.
Score the end of the 8" pipe after reading farther....
Slightly bevel the hole in the 10" pipe where the 8" pipe will go. You are creating a bevel on the outside of the hole in the 10" pipe.
Now with the 8" pipe dry fitted, mark an area ABOVE the surface of the outsude of the 10" pipe... equal to the depth of the bevel. You will create a fillet here and want to rough up the outside of the 8" pipe.
Use PVC cement to glue the 8" pipe into the 10" pipe.
reach into the 10" pipe and grind smooth any protrusion of the 8" pipe into the 10" bore.
Mix up some epoxy and create a fillet on the outside of the pipe intersection.

I know this SOUNDS complicated when you read it... but honestly it will take you far less time than trying to do the rabbet you're talking about and will result in an extremely strong joint. Probably not as strong as using a "T" ... hehehe... but really quite strong.

One final note:
DO NOT... DO NOT... DO NOT... dry sand PVC. Wear a mask when grinding. Only sand it WET (usually SUBMERGED). Take NO CHANCES breathing PVC dust. You body can not process it and it will be with you forever and it has the potential to cause horrible nagging problems.

morbious

10 inch tee's with a 8 inch reducer runs over $200 a pop, and they are over a foot in length, which is too long for the spacing I require. Considering that I will eventually need 30 of these 8 inch "pods", T'ees are too expensive.

Thanks

Hamlin

Have you considered renting or purchasing a "plastic welder"? This will allow you to fuse the two pieces together without worrying about a "rabbit".

__________________
Ken

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