jooshs wrote:

I'm not sure I understand the benefit of the acetone water mixture. Unless you are heating the solution to 100 C, won't there still just be an acetone vapor and increasingly more diluted acetone/water solution?  Do they react chemically?  I can't imagine you are ever heating the solution above 100 C.

As a side note, the best solution I have experienced for a nonglossy smooth finish is still a walnut blaster or tumbler. Any sort of solvent would inherently gloss the surface since the point is to get a melting effect. I have had some great success with a dremel and flapped abrasive buffer attachment, but it produces an uneven result with lots of manual labor for unique geometries.

I think the acetone water mixture is meant for direct application by dip or spray so you can apply a greater quantity without completely melting the print.

That's right, I tried dipping / stir approach as this cases no real danger and under a controlled environment (both time-wise and safety-wise)

I also did a experiment with room-temperature vapor (for the same reasons)
http://www.soliforum.com/topic/1580/yet … g-station/

I'm not sure I understand the benefit of the acetone water mixture. Unless you are heating the solution to 100 C, won't there still just be an acetone vapor and increasingly more diluted acetone/water solution?  Do they react chemically?  I can't imagine you are ever heating the solution above 100 C.

As a side note, the best solution I have experienced for a nonglossy smooth finish is still a walnut blaster or tumbler. Any sort of solvent would inherently gloss the surface since the point is to get a melting effect. I have had some great success with a dremel and flapped abrasive buffer attachment, but it produces an uneven result with lots of manual labor for unique geometries.

I think the acetone water mixture is meant for direct application by dip or spray so you can apply a greater quantity without completely melting the print.

As a side note, the best solution I have experienced for a nonglossy smooth finish is still a walnut blaster or tumbler. Any sort of solvent would inherently gloss the surface since the point is to get a melting effect. I have had some great success with a dremel and flapped abrasive buffer attachment, but it produces an uneven result with lots of manual labor for unique geometries.

It's complicated to set up but looks easy to use once it is.  It would be cool if there was a stand of some kind for the upper section, and then you can keep several jars on hand.  Prep a jar, screw it on, run the pump and then put the next one on.  The problem with the mason jars is it limits the size of the print, and getting the prints in and out without dropping them in the acetone is a bit tricky. 

I wonder if you could do this to a pressure cooker, which is wider and able to be sealed.  Is the pressure inside still lower than ambient after the acetone evaporates?  If so, you don't need a lid that threads or locks, you might be able to rely on a gasket and air pressure.

Point well taken about the size limitations.  The size of the main chamber isn't the main limitation, it's that the secondary isolation chamber (the one on top with the balloon) has to be at least 2x the volume of the main chamber to reach acetone's vapor pressure (boiling point) at room temperature.  I think bell jars are readily available at large sizes, but they're really expensive.  Alternatively, putting several mason jars in parallel, each with a balloon inside would also probably work for the secondary chamber.  The primary chamber can still be a big bell jar, which, though expensive, has the advantage of being really easy to open and close since they typically seal by vacuum to a flat floor pad.  Here's something that looks like it might work really well at $70:

http://www.sciencelabsupplies.com/Bell_ … 4godABkAOA

When the acetone evaporates, it tries to maintain an equilibrium at acetone's vapor pressure, so there should still be a vacuum at about .3 atmospheres after evaporation.  I didn't know that a pressure cooker would maintain a seal in a vacuum, but it seems worth a try.  The main downside I see is that you won't be able to see how the part is progressing inside as you can with a mason jar or bell jar.

I don't like the idea of using MEK at home, I used to deal with it 20 years ago at a inkjet printers. and it would strip your sinuses out if you got to near it. All the rooms had to be heavily ventilated.

Have any had any DIY-solution for this?

-ABS-
In previous posts I mentioned diluted acetone, and I tried that.
My tests showed that the smoothing-effect reduces dramatically when diluting in water.
(I tried 80 / 20 - Acetone / Water) < Worked though, but really slow

-PLA-
I also tried smoothing PLA using caustic soda (flakes) in hot water, no success.
Using high concentration, and no smoothing effect after a full day?

The problems this machine is trying solve with the uneven application of liquid solvent is the reason I went to vapor.   I would like to know more about their claim to smooth PLA however, everyone who knows how to do it says it is not a solvent you want to handle at home.

Well, I don't know if the "Industrial Maintenance Coating Thinner" that they link works, but from the MSDS info, it shouldn't be more dangerous than Acetone, they have the same classifications.

I wonder if you could do this to a pressure cooker, which is wider and able to be sealed.  Is the pressure inside still lower than ambient after the acetone evaporates?  If so, you don't need a lid that threads or locks, you might be able to rely on a gasket and air pressure.

The problems this machine is trying solve with the uneven application of liquid solvent is the reason I went to vapor.   I would like to know more about their claim to smooth PLA however, everyone who knows how to do it says it is not a solvent you want to handle at home.

Interesting.  A couple of people have brought up using diluted solvent before, but I haven't seen anybody up to this point actually trying it before this, so it's nice to see alternative approaches.  Ian, I agree that I'm not sure if this has a lot of advantages over using the standard vapor approaches, as you still have an open tank of solvent (albeit diluted), but now it's much larger and harder to move, and not even a condenser to keep the fumes contained.  Seems a bit expensive and scary to me (spill-risk?!).  These limitations would unfortunately prevent me from using something like this, but maybe it has some ideas worth adapting.

PS:  Ian, I got a v1.0 my own small vacuum-driven smoothing station working this weekend; so I'm curious to have your input about the alternative vapor approach I used:

http://www.soliforum.com/topic/1627/sea … ss/page/2/

Things to note:
-Max object size: 6.5" W x 6.5" L x 8
-Works on ABS and PLA (????)
-Smoothed part does not look shiny
-Using some sort of solvent/stripper by Klean-Strip
  -Possibly 2:1 ratio of klean-strip with water

I wonder how important important the role of the pump is.  I would hypothesis that putting a propeller on the shaft above the print platform would assist with solvent agitation while not requiring a submerged electrical device.  If so, we are talking about a drill in a bucket.  I would think that this could be recreated for way below the $270 early adopter KS.