1 (edited by Retroplayer 2014-07-19 19:45:23)

Topic: Ultrasonic mister for Acetone vapor post-processing?

Has anyone else considered this instead of using heat to evaporate and condense the acetone? If the chamber could be kept chilled enough, the acetone could even be re-used.

We have a tank at work that we use to wash circuit boards which used to use freon (not sure what it is using now.) It keeps the liquid very cold so it will not evaporate and re-circulates and filters it. It uses ultrasonic misting to create a fog within the chamber. My co-worker dunked some of his 3D printed parts in there and was very impressed with the outcome.

Now, chilling and all that is not really necessary unless someone wanted a more professional system, but I think ultrasonic misting will be much safer than heating the acetone. Also much easier to keep the fumes contained.

So, has anyone tried this yet before I start tearing apart my old humidifier?

2

Re: Ultrasonic mister for Acetone vapor post-processing?

Let us know how much it ends up costing you.  Sounds expensive.

SD4 w/ RUMBA, E3D Volcano, all bearings, glass bed

3

Re: Ultrasonic mister for Acetone vapor post-processing?

I tried using an ultrasonic fogger a over a year ago. It didn't go well. It was all part of the smoothing station idea that Tealvince in the projects section on the forum. http://www.soliforum.com/topic/1627/sea … ss/page/3/

It was a cheap version from ebay that is used in some pretty ornaments but they have a fluid sensor in them so it stops if the water level drops, acetone doesn't activate that so it never even came on.
However that was only part of the story as I also found out that the plastic to house the device is safe for use with acetone and t started melting pretty quickly after a few seconds in the cup.
I end up up with a cup full of black acetone and a fogger that I can just about use in water again. I was going to open it up and bypass the water sensor but as using a rice cooker/Presto does such a good job I didn't bother taking it any further.

If you have a stainless fogger tank I am interested to find out what can be done. Pictures say 100 words and all that.

4 (edited by Retroplayer 2014-07-26 00:16:47)

Re: Ultrasonic mister for Acetone vapor post-processing?

Zarni wrote:

I tried using an ultrasonic fogger a over a year ago. It didn't go well. It was all part of the smoothing station idea that Tealvince in the projects section on the forum. http://www.soliforum.com/topic/1627/sea … ss/page/3/

It was a cheap version from ebay that is used in some pretty ornaments but they have a fluid sensor in them so it stops if the water level drops, acetone doesn't activate that so it never even came on.
However that was only part of the story as I also found out that the plastic to house the device is safe for use with acetone and t started melting pretty quickly after a few seconds in the cup.
I end up up with a cup full of black acetone and a fogger that I can just about use in water again. I was going to open it up and bypass the water sensor but as using a rice cooker/Presto does such a good job I didn't bother taking it any further.

If you have a stainless fogger tank I am interested to find out what can be done. Pictures say 100 words and all that.


I'll report out once I get to it. Got the SD4 only a short while ago, so plenty of upgrades ahead of this in the to-do list.

5

Re: Ultrasonic mister for Acetone vapor post-processing?

Have been looking at acetone vapour. Somewhat counterintuitively it seems cold chamber is not the way to go due explosion risk.

MSDS figures for explosive mixture acetone/air seem to be in the 2% (lower) - 15% (upper) range. At 760mm Hg atmosphere that is 15 - 115 mm Hg which corresponds to something like -30 to +10C interpolating from vapour pressure figures in an old copy of the rubber bible.

This suggests a chamber temperature well above 10C - may be a fire risk from leaks but not a homemade bomb. All this is a bit relevant here as we have been having day temperatures below 10C.

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Re: Ultrasonic mister for Acetone vapor post-processing?

jc56au wrote:

Have been looking at acetone vapour. Somewhat counterintuitively it seems cold chamber is not the way to go due explosion risk.

MSDS figures for explosive mixture acetone/air seem to be in the 2% (lower) - 15% (upper) range. At 760mm Hg atmosphere that is 15 - 115 mm Hg which corresponds to something like -30 to +10C interpolating from vapour pressure figures in an old copy of the rubber bible.

This suggests a chamber temperature well above 10C - may be a fire risk from leaks but not a homemade bomb. All this is a bit relevant here as we have been having day temperatures below 10C.

That is counterintuitive! But, there is no pressurized system in what I am describing. In fact, it doesn't rely on condensation which actually requires a lid, either. The vapors are kept within by the temperature differential itself very much like how your grocer can have an open cooler.

At any rate, the chilling part of it was simply to reduce loss of acetone, but not an essential part of this at all.

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Re: Ultrasonic mister for Acetone vapor post-processing?

I know I'm brining this post back from the dead, so apologies.

I'm also looking to produce a vapour chamber similar to an industrial degreaser, with a chilled chamber at the top to prevent vapour escaping,

The other solution I'm exploring is a fogger but from the looks of it most people are struggling to produce something that works reliably.

I'm doing this in a production environment and the goal is to reduce cycle time. currently we use an unheated sealed stainless steel box (700x400x300mm) with shop towels soaked in acetone and an electric fan (12v, we replace it every 3 months as obviously the acetone attacks it) to circulate the evaporated vapour. The parts are hung in the chamber with wire hooks. 

The cycle is 40 minutes currently for the ASA components we produce, and i'm looking to cut that in half without any reduction in quality.

Is there anything anyone can suggest?

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Re: Ultrasonic mister for Acetone vapor post-processing?

I did one long ago.  I used a large pot with a steamer rack in the bottom, and about an inch of acetone.  The pot sat in a tray, or large baking pan.  I coiled copper tubing at the top with ice water pumping through it.  To heat the acetone, I poured boiling water into the outer tray.  The indirect heat was enough to evaporate the acetone, and I couldn't smell it at the top of the pot even with the copper mostly at the edges. 

I usually dipped parts into the vapor without setting them down in the pot.  A 30 second exposure was plenty.  I had to leave it alone outside the pot for a few minutes before evaluating the finish, because the melting would continue for a bit after it was removed.  It usually wasn't necessary to dip it again.  For simpler, less detailed geomtry, I would first give it a rough sanding to knock down the layers a little, and leave the surface dusty.  The dust would then melt and help fill in the texture. 

For a production setup, you could replace the bucket of ice water with a chiller meant for cooling laser cutters (CW-5000) and control the water bath with a souvide cooker.