Vapor Acetone - ABS

[PCVISION]

Hi,

Does anyone, has some tips how to make a Acetone vapor bath for smoothening ABS prints ?
I've seen some pictures and video's but find it dangerous because the fume's are flammable.

Karl of Hyrel send me some pictures but he was talking about a copper tube to put in the water and then the acetone will vaporize.
Only the pictures of the copper tube weren't there. I don't want to disturb him, because he's always working that hard on new improvements.

Thanks !

[Davo]

We may actually offer a flame-free acetone bath accessory. We're looking at doing this.

[PCVISION]

Hi Davo,

Please keep me posted on this one

Kind regards
Jan

[ersdds]

I was fortunate enough to talk to Karl about the acetone vapor bath Hyrel was looking into. I hope I am not misrepresenting him, but it goes like this.

Flammability[edit]
The most hazardous property of acetone is its extreme flammability. At temperatures greater than acetone's flash point of −20 °C (−4 °F), air mixtures of between 2.5% and 12.8% acetone, by volume, may explode or cause a flash fire. Vapors can flow along surfaces to distant ignition sources and flash back. Static discharge may also ignite acetone vapors, though acetone has a very high ignition initiation energy point and therefore accidental ignition is rare. Even pouring or spraying acetone over red-glowing coal will not ignite it, due to the high concentration of vapour and the cooling effect of evaporation of the liquid.[29] It auto-ignites at 465 °C (869 °F). Auto-ignition temperature is also dependent upon the exposure time, thus at some tests it is quoted as 525 °C. Also, industrial acetone is likely to contain a small amount of water which also inhibits ignition.
and
Boiling point 56 °C; 133 °F; 329 K
So we need something to bring acetone to a temp over 140 deg F less than 869 deg F stay away from open flame and stay in an enclosed space (big enough to accommodate the largest build) and preferably have a clear lid to view whats going on inside the vessel. Karl's suggestion was to get a large stock pot (I think he got his from Target) and run a coil of copper tubing in it. If you run hot water through the copper (approx 160 deg F) you can create acetone vapor in the chamber without an open source of flame. Furthermore, if after the vapor has completed it's process, you flush the copper tubing with cold water it is possible to re-condense the vapor back to acetone liquid for reuse.

I constructed an apparatus with the above specifications. If I can upload a picture of what I came up with I will include it. Unfortunately, I found my assembly to be slightly less than effective. Although It worked, it was slow at best. Unless I filled the vessel with enough acetone to cover the coil to get better heat transfer (I used a pan on top of the copper coil to hold the acetone) it didn't generate enough vapor to be effective unless the ABS prints were left in the vessel for hours:(

I decide I would try an electric hot plate on low temp. When I went to Walmart for a hot plate I also saw a Hamilton Beach 5 Quart Oval Shape "Crock Pot" (model # 33156SZ) for about $20. The glass lid even has a small hole that I found you can put a thermometer in:) I found at Keep Warm setting is approx 160 deg F (yea) and even the low setting is approx 220 deg F. Well within spec. It takes some experimentation but it does work. I still need more experimentation which I haven't done yet with respect to time exposure. I have 200 CC Syringes. My thought was to just get the right volume of acetone to fill the chamber with acetone but not so much that there is a lot of liquid. I think that would minimize the amount of condensation on the lid that drips back down and can over expose parts to liquid instead of vapor and use less acetone. Using just 25 CC's of acetone I was able to get a gloss on parts. However the parts I tested were printed at 300 microns. Although glossy each layer was clearly visible.

Everyone includes a disclaimer about working with acetone and it's flammability. I would do the same by saying use extreme caution when using acetone. Be cautious of any potential ignition sources. Also make sure the surface you are working on is sacrificial or not susceptible to acetone liquid.

Hopefully Karl or Davo will get a chance to review this and correct any errors or omissions I have made.