Very strong tape?

Just put the tubes in place with something to space them evenly, and squirt hot glue in the ends and around the fixing holes. Made-to- measure injection moulded bushes (if you're lucky).

My 2p worth is simply to build up a thin fibreglass sleeve where you want it on the inner tube. It's robust and easy to shape.

Fibreglass won't be at all easy to remove if you do eventually make something on the 3D printer, but OTOH it will last indefinitely, so you won't need to make anything on the 3D printer. :)

If I'm visualising the thing correctly I'd think about coating the hole in the outer component with release agent then roughening the inner component and coating that with a strong two part epoxy reinforced with fibreglass. Slide it into the outer and let it cure.

I'm not sure if it would affect your solution but the idea is that it would be stored in pieces and put together to suite the particular job in hand.

I actually put it together today and with only my Mrs 'helping', it was quite tricky to line up because 1) the bits are quite heavy and want to go all over the place and 2) the gap between the sections is only ~1.5 mm or so so unless initially lined up reasonably well they don't go together.

I know the shims though and I think the 1mm ones are solid plastic and so shouldn't collapse under the pressure, if I could fix them in place?

Cheers, T i m

That does sound like the most straightforward solution (and I have resin, catalyst, chopped stand mat, some woven bandage and tissue etc).

I bet.

Good point. ;-)

Cheers, T i m

I get the idea ... to make a 'fitted' sleeve and if it worked, could be a good solution. However, (and knowing my luck), I'd just end up bonding the two parts together! ;-(

Cheers, T i m

It's soft and not really a tape (i.e not sticky) more a collection of fine threads which you can stick your finger through.