Printing hollow translucent cylinders with a sealed end

[THX1138 1]

I have a couple of projects where I'm trying to make candelabras similar to those seen in the game Deus Ex: Human Revolution. I previously made tubes for the diffusers using frosted acrylic and terminated one end of the tube by inserted a solid rod of acrylic, solvent welding, sawing off the rod and sanding down. I was thinking I could get a better look using 3D printing but I only have access to an Ultimaker 2 (I think a 3 would be easier) so I need to split the tube into two parts. I'm not sure if I will be able to get them to join seamlessly but I'd like to try anyway.

I designed the tube parts to have a lip where they meet in the middle so they slot together. I figured I could maybe apply solvent in the corner and then slot them together. I was wondering how an acetone vapour bath would affect the translucency.

The intended tube length is 33 cm. The wall is 3 mm but only 1.5 mm for the lips.

Edited December 4, 2016 by Guest

[Labern 774]

I maybe missing something here but If only one end is sealed then print it upsidedown with the sealed end at the bottom.

[THX1138 1]

I maybe missing something here but If only one end is sealed then print it upsidedown with the sealed end at the bottom.

 

Thanks for your response!

Would that mar the top of the tube? Would the tube termination be more flat that way?

Also have you any idea whether a 1.5 mm thick lip is thick enough or would it be liable to chip?

And would translucent PLA still look frosted after an acetone vapour bath?

[Labern 774]

Acetone gives PLA a white powdery stuff randomly over it.

Acetone works better on ABS. And chloroform works best on PLA.

1.5 lip would be heaps.

Sorry I don't understand what you mean by "Mar the top"?

[THX1138 1]

Acetone gives PLA a white powdery stuff randomly over it.

Acetone works better on ABS. And chloroform works best on PLA.

1.5 lip would be heaps.

Sorry I don't understand what you mean by "Mar the top"?

 

Oh right, thanks!

The finished tubes will be quite tall at 33 cm. I had been thicking of using a polypropylene bucket with a lid for the vapour bath but apparently polypropylene is less resistant to chloraform than acetone. Do you have any ideas? I'm sure I'll find something I can use in any case.

Edit: I think I can use a cardboard postal tube. Of course I won't be able to use the plastic end caps but I can probably use wood or something.

I thought that the bottom of a 3D print might be the ugliest part. I figured the plastic might stick to the base plate of the printer a little unevenly causing visible surface variations. I'd like the top of the tube to be as uniform as possible with no marks from where it was pulled off the base of the printer!

Edited December 4, 2016 by Guest

[Labern 774]

If printing on glass bed then The bottom of the print has the best finish. Shiny and smooth.

I vapor smooth in a glass jar but a tall item like this may give inconsistent results as more vapor will sit at the base and not reach the top of the print. Maybe wiping chloroform on it with a lint free white rag. Just keep sniffing to a minimum

You could use XTC-3D smooth-on coating which will make it more like glass.

[THX1138 1]

If printing on glass bed then The bottom of the print has the best finish. Shiny and smooth.

I vapor smooth in a glass jar but a tall item like this may give inconsistent results as more vapor will sit at the base and not reach the top of the print. Maybe wiping chloroform on it with a lint free white rag. Just keep sniffing to a minimum

You could use XTC-3D smooth-on coating which will make it more like glass.

 

Thanks for all these tips!

Making a glassy finish might be interesting (my prior method used matt frosted acrylic) but is there also a way to make the surface smooth but with a matt/non-reflective finish?

[Labern 774]

0.1 layers are pretty smooth so I don't think you will need any treatment.

[gr5 2,172]

Treating ABS is easy - acetone vapor. Treating PLA is not easy. You should do some small (1cm) parts and test treatment first. Acetone does pretty much nothing to PLA but if you use PLA/PHA from colorfabb and completely immerse it for 30 seconds it looks pretty good.

There are many solvents that dissolve PLA but they change it chemically and parts can break/split/discolor and do everything you do want and nothing that you do want typically.

There are many other materials that you can print but I don't know if and what chemicals can smooth them:

ngen is a great material - easy to print like pla. Easier than ABS. I have no idea about solvents.

XT is very transparent. I've seen impressive results but you have to print slow and overextrude a bit (set flow high - 130%? Not sure - experiment). Again - no idea about solvents.

Most solvents are likely to make it go from transparent to milky. Which I suppose is just what you want.

Keep in mind that printing the top of a cylinder works pretty well - not as well as printing the bottom on glass - but not too bad either. The printer "bridges" the gap across the top of the cylinder. This works well with most materials (nylon, pla, abs, ngen, xt) but not well with others (PVA doesn't bridge well).

[Labern 774]

Yes acetone works on colorfabb PLA/PHA but this will leave white residue on the print after it fully dries.

Chloroform on PLA won't crack it or harm it to much. It does soften the outer layer a bit but this hardens after a few hours

If he would vapor treat abs he would have to fly it down as it's very tall to give and even treatment but lying it down will mark the side.

XT is very clear but has the tendency to leave brown spots. I would recommend it on long prints if you want it in this case.