SpudFiles

I have a schedule 40 DWV 8x4 reducer. I am planning on using it for a big combustion. I had some 8" drainage pipe but it is too small for the fitting. I have a line on some sch80 8" from a friend instead. I was planning on making a plug myself for the other end. Any suggestions on what kind of cannon to make or how to make the plug would be awesome.

Large scale epoxy casting?

I would but I don't know where to get a gallon jug of epoxy.

Thick wood?

Hardware stores sell gallons of fiberglass resin. Thats basically epoxy, or sometimes polyester that should be fine if you make it like atleast an inch thick. You would probably only need a quart though.

I got a 21' stick of 8" pipe, and I got the same problem.

You could cut multiple plywood circles slightly oversize, and turn down on a drill press. That is going to take some rigging, and a drill press. Multiple disks could be screwed/ glued together, then fastened to the pipe via multiple screws through both the pipe, and disks.

I know not very easy to do, and perhaps that is why I have not done it.

Does it fit over 8" Sch 40 PVC? IF it does, I'll buy it off you.