How do I give 3D-printed parts in ABS a shiny smooth finish?

Question

The surfaces of my printed parts using ABS plastic look rough and uneven.

What methods can I use to achieve a smoother finish for my for 3D-printed objects?

I realise this is something almost everyone is familiar with, but it still needs to be asked. — Morgoth, May 19 '17 at 14:16
It is a good question, and one I would like to know the answer to (I am certainly *not* familiar with it). — Greenonline, May 19 '17 at 14:57
For PLA, see [How do I give 3D-printed parts in PLA a shiny smooth finish?](https://3dprinting.stackexchange.com/questions/11/how-do-i-give-3d-printed-parts-in-pla-a-shiny-smooth-finish) — Greenonline, May 31 '17 at 06:24

score 5 · Accepted Answer · edited May 19 '17 at 15:03

Acetone can be used to smooth ABS.

The left has been smoothed by an acetone bath and the right is the original model. (Image credit: Andrew Sink)

Take note: acetone is dangerous to breathe in, so work in a well ventilated area. It is also flammable.

Warm acetone vapour bath using stove

This method involves suspending the model in a glass jar of boiling acetone that is heated up by a pot of boiling water.

Attach the model to the lid of the jar with some string, keep the string short, so the model is close to the lid.
Put a few centimetres of water in a pot
Place a rag at the bottom of the pot (to keep the jar stable).
Place the glass jar in the pot, on top of the rag.
Place the pot on the stove and heat to 110°C.
When the acetone is boiling place the dangling model into the jar.
After a few seconds, remove the model.

See here for a step-by-step guide with pictures.

This method elevating the model in a glass jar of acetone that is heated up by the printer's heatbed.

Find a non-soluble object that the 3D model can stand on.
Put a teaspoon of acetone in jar.
Place the jar on the heatbed and heat to 110°C.
Place the stand into the jar.
Place the model on the stand, the stand should not let the acetone touch the model.
After a few minutes, remove the model.

See here for an example.

+1 - However... Even though the model on the left looks "nicer" and "more shiny", it should be noted that some of the original detail appears to be lost, (obviously) due to the dissolving process. — Greenonline, May 21 '17 at 15:06
This has not worked for me, neither has the rotary rock tumbler — K Mmmm, Dec 12 '19 at 20:36