How to make your ABS prints shiny

An acetone vapour bath is used to make your ABS prints (will not work with PLA) look shiny and feel smooth rather than having that ‘lined or layered’ appearance and feel. This is a step by step guide on how to process your prints so that they are smooth and shiny and all without costing you a fortune.

How it works:

The process basically melts a small portion of the outer layer of the ABS and then this fuses together to form a continuous surface. You can also use this process to make you parts watertight, as parts straight out of the printer will generally not be waterproof.

Items required:

  • Plastic tub with lid large enough to hold your print
  • Paper towel
  • Aluminium foil
  • Acetone
  • The object you want to smooth


Make sure you follow safe handling procedures as described on the acetone bottle as acetone is a hazardous substance. Place the tub in a well ventilated area so that you don’t breath in the fumes.


  1. Tear off enough paper towel to completely cover the bottom and sides of the plastic tub

Tub lined


2. Tear off some aluminium foil and make sure it will fit inside the tub and also hold your print on top of it, make it double layered to be safe. Then curl the sides/ends to make it sit off the paper towel a little bit. The purpose of the aluminium foil (and why it should be raised) is so that the acetone doesn’t come into contact with your print because that will damage and melt it. Test to make sure the foil sits inside the tub and that your print sits on the foil without touching any of the paper towel.

Tub foilFoil bent


3. Remove the foil and print you tested for fit. Pour acetone into the tub so that the whole bottom paper towel surface is wet (but not swimming). The acetone will ‘wick’ up the sides and evaporate to fill the tub with vapour.

Tub soaked


4. Place the foil inside and the part on top of the foil, make sure the part is not in contact with any of the towel or it will stick to it and may melt.

Tub parts


5. Place the lid on and wait. The time needed will vary depending on the size, geometry, infill and perimeter layers of your part. Generally small, low infill parts could be done in 1 hour while large more solid parts will take up to 3 hours. You should periodically check the parts to decide when to take the lid off and air the tub out. Note that the parts will continue to smooth/shine even when you take the lid off because the acetone in the air and on the part is still evaporating. Once you have taken the lid off wait for 30 mins to an hour before touching the parts to make sure they are fully dry and won’t smear when you touch them. Now you’re all done!


Before vapour bath:
Before guard 1

After vapour bath:
After guard 1



If you leave the parts in too long and/or they are get too weak from the melting process then your parts could collapse/melt. This circular sculpture has structural arms that need to support their own weight so once it was left in the vapour bath too long they collapsed under their own weight as the vapour bath made the outer layers softer and weaker.

Main sculpture circular