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How do i thin out the wall of a PVC pipe? Answered

Hi there everyone

I am in a process of building a PVC bike trailer out of 40 mm PN 20 type of pipe.

At the neck of the trailer where the cross-shaped yellow piece swivels horizontally - permitting the trailer turn left and right - , and just under it, where the lower red elbows swivel vertically - permitting the trailer to move up and down - are the two white pipes that i want to shave 1 or a bit more mm off of.

I bought the materials but in a very interesting way the pipes don't fit inside the fittings. They need to be warmed up and then they fit inside one another getting stuck forever. No glue needed. 

If i buy  the next largest fitting size - 50 mm - the gap is just too big. So it's a no go.

That's why I ask you people: How do i shave off 1-2 mm of the white pipes in the picture so they slide in easily in the fittings? I want to point out that unfortunately I don't have access  to any heavy-duty machinery. So a manual way of doing this would be much appreciated. 

P.S. the red dots on the picture are fixed points or dabs of glue if you like. The green dots mark out the movements of the components. For example the yellow cross is glued to the green pipes witch are glued to the red elbows witch in turn are glued to the other green pipes. Here only the yellow cross swivels on the vertical white pipe. :) I hope you got it :)



Reply 5 years ago

You could try using an actual lathe, I guess?

Or what about heating the tube and rolling/stretching it to a smaller diameter?

smart one! yeah, the heating and rolling technique actually works! not as precise as a lathe of course, but got the job done, thanks!

Cool, you're welcome.

The 1st tool I'd probly grab is the belt sander. Just keep it moving, don't stay on 1 spot long. I oft tie or clamp a belt sander upside down on bench so I can move workpiece against it. In this case, keep pipe rotating.

Ideally? Machine lathe. Perfection.

Don't have access to a machine shop? PVC will be worked by any tool used on wood. Maybe slower. risk of melting a bit and gumming up the blade/ sandpaper IF you are impatient and bear down too hard.

Another option is epoxy to fill big gaps. If u do that, I suggest hot flanging the pipe, and hot constricting the end of the fitting. (drawings to follow)

I use a Dremel tool with a round sanding drum to enlarge the inside of PVC


Wedge a cork or bung in the end, with a dowel in the cork.
Put the dowel in a drill-chuck.
Spin the drill up, and then file or sand the tube as it spins.


hm...interesting approach, but isn't the filing or sanding generate heat? that would not be the best. The PVC gets really sticky at higher temps...

I will try it anyway. :)


5 years ago

ups! the picture didn't uploaded. I'll try to upload it here

model for instructables.jpg