smoothed ABS unicorn, by Pipe951

One of the first things that I saw when looking on the net on the topic of 3D printing was these glass looking prints.

This sort of blew me away how good they looked.

It makes the 3d prints look like a solid plastic with a glass like finish.

I saw many ways how people did this trick and though I would give it a go.

Of cause YouTube to the the rescue, try looking for vapour smoothing.

I tried dipping the print into it an acetone filled bowl, tried brushing it on.

Some techniques are complicated and some easy.

This is my process,

The main difference is the gas camp stove for near instant vaporisation off the acetone.

Disclaimer Acetone vapour is highly flammable, care must be taken, don’t do this process inside your home. try at your own risk.

Im sort of impatient and this technique is quick, the issue of even smoothing is an issue other techniques can have. Some use ways to move the vapour around. The problem is acetone vapour is heavy and will sit at the bottom of the bowl. This has an effect of smoothing the bottom more than the top of your print. To get around this problem I want the vapour to rise very quickly.

gas camp stove

Stuff you need

You need a non-flammable vessel/ bowl of some sort. A glass sheet to cover the opening of the bowl and a camp gas oven. You can use electric hot plate, probably safer but it’s slow to heat up.

You will also need a jig to hold your ABS prints in place, it need to be above the bottom of the bowl. A jig is need to suspend the object in the vapour cloud and to keep your print out of the acetone puddle. You can’t touch the print with your fingers as the gloss finish will be damaged when it’s still soft. But you may like your finger prints on the surface 🙂

I use wire jig for hanging or a board with nails in it to hold the print above the bottom. the nails give the bottom a near 100% gloss finish.

Make a jig to suit your print, its not critical.

Ok you have your finished ABS print and you want shiny like glass.

Tip, this technique only works on true ABS filament, some brands of ABS filament are made to be low warping. These filaments will not vapour smooth!

I use 3dfillies filament, its made in Australia (support the locals), its a good price, prints really nice, great colours, doesn’t stink when printing and vapours smooths really nicely.

Steps to a shiny print

  • You’re in a well ventilated area.
  • Place bowel on the gas camp stove that you tested before this step.
  • Place or hang the ABS printed object in the bowl so its just above the bottom surface.
  • Pour a small quantity of acetone into the bowl, about two lid cap fulls.
  • Place a glass plate over the top of the bowl
  • Switch on the gas burner on will you see the glass plate just gets a layer of acetone condensation. 4 second burn will evaporate the acetone completely, dependant on ambient temperature
  • Wait for the desired gloss finish. Usually 10 to 20 seconds.
  • Remove the glass plate and lift the jig out carefully with out touching the print.
  • Let the print gloss cure, it will be quite soft at this stage.

If you’re using a flat lowering jig, place some sort of release agent, silicone lube or soap on the plate. If you don’t do this your print will be stuck to the plate when the ABS sets.

You don’t need much acetone, just enough to form a vapour cloud. over time you will know what is enough.

When you switch the gas burner on you should see the vapour rise, it looks like a wet line rising on the bowl inside surface. You know when the bowl is full of vapour, vapour will condensate on the glass.

Second warning

Don’t let the vapour on the glass form into droplets. You have the gas burning for too long. These droplets will fall back onto your print causing stains.

How long do you leave it in the vapour.

Good question!

It depends what finish you want, there is a trade off.

The longer you leave the print in the vapour cloud the small details will be lost.

If you leave it in two long it will look like a melted snowman.

Your exposure time is too short, lots of detail, print layers will be visible.

How long to the ABS sets

Good question, it depend on your ambient temperature. On a hot day 10 min to touch. cold day 30min I leave the prints for 24hrs and I know its tough by then.

Oh yeah cold day in Adelaide is 4 deg C, hot day is 38C and above.

Third warning

When you take your print out of the bowel you fill feel that the vapour is sitting in the bowl. This is a hazard as acetone is heaver than air!

So to be safe tip the invisible vapour out of the bowl like you would with water. then leave the bowl upside down propped up on an angle. this will make sure there is no acetone vapour pooled, ready to make your life exciting.


I have made lots of things that are vapour smoothed, this is why I love ABS.

ABS has its negatives but smoothing, acetone gluing and high temperature resistance make ABS a winner for me.

Some of my smoothing has formed micro cracks over time in the surface. this may be due to over smoothing or cheap crappy ABS I did use.

Some prints get a cloudy finish, this seem to occur if I try to smooth multiple times. I do this if the smoothing still shows the layer lines, so I do the process again.

I find the cloudy effect is sometime desired.

Have fun smoothing.

73’s Adrian