Ways to increase the ID of 6" PVC Pipe

[Anthony Whitesell]

Unsure how to title this post, or where to put it.

In the on going conversion of my dust collection system to 6" PVC, I need to get the 6"x4"x4" wye off the inlet and connect direct to 6" PVC piping. The OD of the inlet is 1/8" larger than the ID of the 6"PVC SDR pipe. Almost fits, but not quite. Due to the expense of the fittings, I'd rather not modify a fitting (ie., heat to expand it to fit). What I need are ideas on how to open the ID of a 3 inch long piece 6" SDR PVC pipe by 1/8". I thought about a lathe, but if it is not perfectly round, the lathe won't remove the material evenly. Any other ideas?

[glenn bradley]

Spindle sander is what I have used on 4" pipe. I found it easier to heat gun the pipe and push it onto the nipple. This can be easier with the gun mounted or held in a clamp thus leaving you free to rotate the pipe to soften and press on without having to worry about where the heat gun should suddenly go

[Paul F Franklin]

I know you said you don't want to heat a fitting, but you should be able to heat a short piece of pipe and get it slide over the inlet while the other end slides into the fitting. Gentle heating with a heat gun will do the trick.

If you don't want to do that, you could use this method:

Take a short piece of pipe and cut a slit along its length. Slide that over the inlet. Put another short piece in the fitting and slide that into the slitted pipe until it butts against inlet. drill a few pilot holes and use short screws to mechanically hold everything together and then wrap the connection with foil tape.

Method 3: A 6" fernco coupling can probably be convinced to slide over the inlet.

Method 4: Buy a length of 200mm heat shrink tubing, adhesive lined, and use that to connect the inlet to a short piece of pipe. You can get in on the big A for 10-12 bucks for a meter long piece. The stuff is very strong when cooled after shrinking.

[Anthony Whitesell]

I know you said you don't want to heat a fitting, but you should be able to heat a short piece of pipe and get it slide over the inlet while the other end slides into the fitting. Gentle heating with a heat gun will do the trick.

I see where you are going with this. Adds 3-4" to the length of the fitting at the floor level. But would work.

Take a short piece of pipe and cut a slit along its length. Slide that over the inlet. Put another short piece in the fitting and slide that into the slitted pipe until it butts against inlet. drill a few pilot holes and use short screws to mechanically hold everything together and then wrap the connection with foil tape.

Unfortunately, the ID of the expanded outside sleeve would not be large to allow a piece of pipe to fit inside and too large for a fitting's street end to fit.

[Anthony Whitesell]

Spindle sander is what I have used on 4" pipe.

That was my first thought. Second was trying to use a 1/16" rabbet bit and a pattern following bit on the router table. Seeing if there are any other bright ideas from the creative people here.

I found it easier to heat gun the pipe and push it onto the nipple. This can be easier with the gun mounted or held in a clamp thus leaving you free to rotate the pipe to soften and press on without having to worry about where the heat gun should suddenly go

I think it would expand easy enough, but the fitting would never be usable anywhere else or in any other way. Modifying a $1.14 piece of PVC pipe is a lot less expense than modifying a $18 fitting.

[Bill Dufour]

Hot box, heat blanket. Theoretically boiling water since PVC softens starting at 200 degrees F. Maybe oil or antifreeze.
My Dc I had to go from 5" to 6" pipe. I cut out a wedge about 12" long and. zero to 3.1415" wide I used a heat gun and hose clamps to make a funnel. Use harbor fright welders gloves to move the pipe. Calk and duct tape filled any errors.
BilLD

[Lee Schierer]

This would seem to be an ideal task for someone with a 3D printer to make a short transition piece.

[Jack Frederick]

Not sure exactly what the od’s are, but Mission Bands might have a solutioin for you. They have a very wide ranging product line and are of excellent quality.

[Tom M King]

PVC pipe becomes very pliable with heat. I've made some 6" smaller with a heat gun and hose clamps, but never enlarged any. I'm sure it can be done though. The hard part will be setting something up so you can spin the pipe to get the heat all the way around it.

A variation of this video.

https://www.youtube.com/watch?v=-X1He24pcsE

[Bruce Wrenn]

I've used this technique to swedge 4" PVC to 4" metal. On the pipe, add a couple worm gear hose clamps at the very end. Tighten, but not too tight. Stand that end upright in a pan of boiling water, and let it stay there for a couple minutes. Remove from water, and immediately, using a cordless drill, tighten hose clamps, shrinking pipe's outer diameter. Once pipe has cooled down, remove clamps. Practice on a couple pieces of scrap to get technique down pat. The PVC, that I swedged to metal has been in use for almost twenty years.

[Barry Versteegh]

If you have a wood lathe turn a mandrel about 6 inches long to the inside of your plastic pipe to be a guide to keep everything straight. then increase by a taper around a 1 inch long to the ID of the larger pipe then turn larger shoulder for as long as needed. Heat the end of the pipe with heat gun till it softens and push the wooden form in. After it cools off remove the form and then cut to length.

[Jim Becker]

Heat. Turn a wooden caul on your lathe to match the diameter of the inlet you need to get your plastic pipe to fit over that has a short flat spot and then a slight slope down to the normal ID of the pipe. Heat the end of the pipe gently with a heat gun or boiling water or by whatever method you are comfortable with and force that over the caul you made when it's darn hot. You should be able to expand the pipe just enough to slip over the inlet by enough that you can fasten it securely by the means you prefer.

BTW, this is a somewhat "normal" challenge for dust collection systems. Even those of us who use metal quick connect type duct work have to have a "machine adapter" sized for whatever the inlet on the specific dust collector happens to be. There's no real standard other than nominal numbers like 6", 5", etc. Sometimes the inlets are smaller and sometimes they are larger. Same goes for the ports on machines.

[Jerome Stanek]

6" furnco coupler

[Ronald Blue]

Why not the Fernco coupler as has been suggested already? About $15 give or take. That's at Menards and I didn't look anywhere else. 6 by 6 straight coupler has an ID of 6.6 roughly. Also very forgiving and if you were to need to disassemble for some reason can easily be taken apart and put back together. I could see the PVC becoming weak if it has to be enlarged to far.

[Bill Dufour]

I suppose a Cherne plug would make a great expander. You would need an outside containment ring, coffee can?, so it does not expand too far in one section.
BillD