I did manage to do this - it’s a bit mongrel - I made a new circle, then made a cylinder, then shelled to 1.7mm. That was ok.
Then I made a smaller circle, into a cylinder, shelled it and stuck it on top. Somehow I’d need to stick it on the top of a tentacle section I guess.
I attached a pic of my tube-on-a-tube
I managed to “glue” my mini tube onto the tentacle end but it really is quite mongrel; I’m sure there’s a better way of doing it. ANything you can recommend I’ll give a go.
I attached pic 023.
Off for some sleep now but I am making progress I think.
cheers
Barne
Sorry mate in the middle of a house purchase at the moment so haven’t been online as much as I usually am. Hopefully you can get it sorted.
The easy way would be to just create one tube smaller, slide it inside and the union them. It might get a but more fiddly if these parts slope towards a cone (larger at one end than the other.)
The section view could be your friend here too so that you can see what’s going on in the inside, particularly if you wish to chamfer/fillet the internal edges.
No worries, I’m grateful for whatever time you have to help - you’ve helped heaps! No one else in the community has jumped in yet haha 
Plus I’m in no hurry I’m making sure I can learn this stuff. I’m still wrestling with my 3D printer calibration that is all over the place.
Hope the house purchase goes well!
I have finally got my 3D printer working reasonably well and am experimenting with printing my octopus tentacles. Not going too bad. I’ll take a little video.
One of the two final things I’d like to learn is to make 3 sizes of little half circle cups 10, 13, 17mm in diameter - just like octopus sucker cups they have on their tentacles. I thought a great way of attaching these to the backs of the tentacles, would be to have a little 2.5mm diameter, 2.5mm high “stalk” on the top of each cup. That way, I could poke the stalk-cup into a 2.5mm hole in the tentacle, maybe with a little glue.
I’d need to learn two things (you might be able to suggest where a good tool to
start would be) - 1, make the cup and glue (union) a stalk on the top, 2, make a template kind of thing where I could just get a tentacle and “copy” a 2.5mm wide hole that goes through the 2mm shell, to wherever I wanted to place a sucker cup.
Anyway in the interim - I hope your house buying went well
Hi Shaun,
I just wanted to say a big hi for helping me work on these new skills - I am practising and will actually shell out for a more reliable printer than the one I have which frequently has issues.
I think I should have the sculpture done (I hope) by end July. If you or anyone else wants to see pix etc once it’s done I’ll post them on my Instagram @onekickduck and website www.onekickduck.nz
thanks again!! 
Hey mate,
I’ve been away a while as moved home and took some time off work. Your website is amazing, glad that you’re improving 
Ive also got my eye on a new printer, the Bambi P1S, but it’s low on the priority ladder compared to my wife’s home making plans 
Hi Shaun! My new Bambu A1 3D printer should be here early next week. Not as cool as the P1S but much more reliable than the tired and temperamental cr-10 mini - you can do two identical prints in the same spot, same filament and settings one right after the other - one will be ok the other will be wonky and with errors.
Good that your new home is coming along, you just need to get your wife enthused in 3D printing now haha.
I’ll sketch out my idea for the octopus sucker cups and if you have time, maybe suggest what technique I could consider for them.
cheers
Barney
Hi Shaun here’s my idea for the 3 sized sucker cups. I’d try and print each one with a little stalk on the top, and apply a little glue to stick it to a hole on the side of the tentacle. Big suckers near the thicker part of the tentacle, smaller ones near the bottom.
The tentacle would need little 2.5mm holes randomly scattered on one ‘side’ of each tentacle - I don’t know if there is a Ctrl-C, Ctrl-V or similar function in Shapr3d that could be used, rather than manually making lots of holes?
Thanks for the kind words on my site! It’s not my real job but keeps me sane. If you know anyone who might want an illustration of mine on a T-shirt etc, send them the link haha. There’s lots of things on my onekickduck Redbubble store.
Anyway, hope the house is going ok, and I’m expecting my new printer to be here either tomorrow or the day after - then it will be mass tentacle printing
ANother option which might be simpler is if I can somehow do copy and paste of little bumps on the surface of the tentacle, to save printing new bits and gluing. This would give the impression of bumpy rather than smooth tentacles. I’m sensing somehow this is a “pattern” within Shapr3d
