Plastic tube with 28mm internal bore?

[jim_in_sussex]

25mm plastic conduit (internal bore around 22mm) makes an ideal sleeve for 15mm copper tube passing through a wall.

I've looked and looked over the years but never found anything with quite such a good fit for 22mm tube.

There's about 3mm all round a 15mm tube with 25mm conduit. Based on that the tube needs to be around 28mm internal dia or 31mm o/d.. 32mm waste is around 35 o/d - rather more play than ideal.

Any suggestions please?

TIA

[John Stumbles]

28mm Hep20, but expensive unless you have offcuts