Need coupler for 2 plastic fittings

[Mike Stelts]

Just in case someone knows the answer offhand, I'd like to save an afternoon of trial fittings at a supply house...

I want to connect two 4" plastic fittings (without using a short piece of hose and two hose clamps). In this case, I'm connecting a wye to a 4-3" reducer.

Is there commonly available pipe size that can couple these (4" I.D.)? If there's something close but slightly loose, I'll fill it with caulk.

[Sam Force]

Maybe I'm confused but why not a piece of 4 inch PVC pipe?

[John K Jordan]

Just in case someone knows the answer offhand, I'd like to save an afternoon of trial fittings at a supply house...

I want to connect two 4" plastic fittings (without using a short piece of hose and two hose clamps). In this case, I'm connecting a wye to a 4-3" reducer.

Is there commonly available pipe size that can couple these (4" I.D.)? If there's something close but slightly loose, I'll fill it with caulk.

I don't know what's available commercially, but when I couldn't quickly locate couplers I needed for my dust collection I made them from PVC pipe starting with a ring cut from piece of pipe. If the diameter needed was slightly smaller than the pipe, I stood the ring on the bandsaw table and cut a slice from the ring calculated to give the needed circumference, then glued the ring in place to make the coupler. I often used short sheet metal screws to hold joints together, for example clear plastic to PVC. Don't know if something like this would work for your type of plastic.

[Jim Becker]

If these are regular PVC/ABS plumbing type products a short piece of pipe from the same series/designation for the fittings should work just fine. If these are those pre-made "dust collection" fittings from a woodworking store...well...not really standard stuff.

[Mike Stelts]

Jim answered Sam's question, "4-inch" dust collection fittings are about 3 7/8". The closest I have in the barn is sewer and drain, which it 3-15/16". Unless someone knows of a 3-7/8" pipe, I'll use this, or I'll see if I have something the right size to try John's idea.

[Bill Dufour]

I. remember the tall pineapple cans are a good slip fit into 4" pvc foam core pipe.
Bill D

[Mike Stelts]

All fixed with sewer & drain pipe, screws, and caulk; however, I won't post any pictures of this masterpiece.

[Lon Crosby]

For PVC, heat up a piece of pipe and squish it down to the right size - or expand it with a tapered jig. A hotplate and a pot filled with antifreeze solution works well. Can also use a heat gun but that takes more skill to heat the pipe evenly. Wear hear resistant gloves, preferably water proof. Professional results.