Acetone Vapor Finishing Device

Ok, I have seen many different videos on AVF and most have the same theme. Pour acetone in a glass jar, heat it to 120c stick part in for a few seconds and remove.

There was one though that used an bucket of icewater, pump and a deep fryer. The general theory of that one differs in that it recovers at least some of the acetone vapor and is less wasteful in that aspect. It also reduces overflow of vapor into the room by condensing it back into liquid acetone.

So, my thought gears got turning. Dangerous I know. My thoughts were how to generate the cold efficiently and preferably with no moving parts thus reducing the chance of sparks. Ice isn't an option, messy and PITA. Then also generate heat in some safe fashion. So, my experiences as an overclocker came to mind. Pelters. Or Tec (thermoelectronic cooling device). One side gets hot, one side gets cold. One device generates both heat and cold (well, generates isn't exactly what it does but its a loose enough term for now but more properly moves heat). No moving parts. Hot side could heat the acetone, cold side could chill circulated water for vapor recovery.

Found this one..
[www.ebay.com]
I don't believe its really 400w but should be enough. But will it generate the 120c needed to boil the acetone? Is there a better chip that someone knows about that can stand the high temps needed here?

Any thoughts on this? Has anyone tried this concept out?

---

If You Can Read, Thank A Teacher. If You Can Read It In English, Thank A Veteran That's what you do in a herd: you look out for each other. - Manny from Ice Age

New to 3D printing, not new to 3D or tinkering. LulzBot Taz 5 Generic Chinese 50w 300x500 Laser Cutter/Engraver (Ebay:171066211150) Corel X7, Photoshop CS6, Lightroom 4, Modo, Hexagon, Bryce, Poser

Acetone boils at about 56C.

That Peltier junction device is like any other semiconductor - you'll have to be very careful to ensure you can dissipate the heat it produces or you'll kill it very quickly.

Your idea seems overly complicated to me. Acetone isn't expensive or toxic enough to bother with vapor recovery. I think a real problem to be solved is circulating the vapor so it treats the entire surface of the printed part evenly. I think that could be done by using a motor outside the vapor container to rotate a metal fan blade inside the vapor container.

Quote
the_digital_dentist
Acetone boils at about 56C.

That Peltier junction device is like any other semiconductor - you'll have to be very careful to ensure you can dissipate the heat it produces or you'll kill it very quickly.

Your idea seems overly complicated to me. Acetone isn't expensive or toxic enough to bother with vapor recovery. I think a real problem to be solved is circulating the vapor so it treats the entire surface of the printed part evenly. I think that could be done by using a motor outside the vapor container to rotate a metal fan blade inside the vapor container.

It does boil around that point. However being a dense vapor it cools rapidly as well. So by heating it well beyond boiling you ensure an ample supply of vapor present to displace any oxygen in the vessel. This does two things, provides dense vapor for ABS smoothing and removes oxygen reducing or eliminating the possibility of an explosion or fire. The most dangerous time is when the vapor to oxygen ratio is at the correct percentage to support combustion. Lower or higher and the risk is mitigated. In my short stint of playing with this, I have found that heating to 110-120c until I see condensation completely crawl up the glass jar side and then reducing to 80-90c as a maintenance temp seems to work out very well. It fills the jar quickly limiting the risk and then produces sufficient vapor replacement to offset condensation on the jar and ABS parts. If you have information as to a better method, I would most appreciate you sharing it with me so I can improve my process.

Well, I didn't think it overly complicated. Yes acetone isn't expensive but it is toxic and has a noxious smell and I would rather not have its vapors pouring all over the place. Plus, with a temp controlled heater, uniformity and consistency could be achieved. Simple arduino based controller to deal with the temp. And it all could be housed in a simple enclosure for portability. A big bucket of ice water isn't so portable.

And yea, I know the heat and cold would have to be dissipated, that is actually precisely what I intended to do. A sufficiently large aluminum block under the acetone vessel would suffice for the heat distribution and transfer of heat to the acetone. And a cooling block commonly available for use with computer liquid cooling systems could be used on the cold side (normally placed on the hot side) and would facilitate connection to a liquid cooling pump (also part of a typical computer cooling system).

As for circulation, I believe that is self accomplished by the device itself. Cold sinks, heat rises. Natural convection would occur as the cooled condensed liquid flowed down the outsides of the vessel while the heated vapor would rise naturally in the center where the part(s) are. This should produce a natural torus of convective movement inside the vessel. If a fan is needed magnetic coupling could easily transfer rotational energy to a device mounted inside the vessel to rotate a fan with no risk of fire. It could be 3d printed parts (PET) and simple neodymium magnets neither of which are capable of producing a spark.

---

If You Can Read, Thank A Teacher. If You Can Read It In English, Thank A Veteran That's what you do in a herd: you look out for each other. - Manny from Ice Age

New to 3D printing, not new to 3D or tinkering. LulzBot Taz 5 Generic Chinese 50w 300x500 Laser Cutter/Engraver (Ebay:171066211150) Corel X7, Photoshop CS6, Lightroom 4, Modo, Hexagon, Bryce, Poser

Heating acetone is not needed. Acetone vaporizes at room temperature and is heavier than air. I saw a video 2 years ago about using a paint can, paper towel and couple of magnets and I have been doing this way ever since and it works perfect. It's just not as fast as the heated method.

What you do is take a metal can (needs to be big enough for your part with a little extra room to spare) and line it with a folded up paper towel around the inside, I use small magnets to hold the paper towel in place (on small soup cans I put the paper towel in the bottom) you then put just enough acetone into the can so the paper towel will absorb it but not drip (if it drips, shake it out a bit until it stops). Now I place my part inside another metal tin (like an old cookie tin) and then place the can over it. Most of the time it takes 45 minutes to 2 hours depending on the size of the model. You can simply lift the can to check on the progress. Once it's done, simply let it sit overnight to harden (evaporate all the acetone from the plastic) and it's done.

Here is the original video I saw. I did modify mine just a little as I use just old soup cans, coffee cans and cookie tins (cookie tins are good as well, put the paper towel in the lid, then just put the part inside the tin and place the lid on (with acetone of course).
[www.youtube.com]

Correct. You do not HAVE to heat the acetone. You can contain it and let it work on the part for hours. And hours.

By heating it you shorten the process substantially. And yes I did it a couple times with the towels and a glass jar. Took like 5 hours. The print took less time than the smoothing. The same process is done in 10 minutes or less (including the heat up time) by using the printer bed heater and the same glass jar. Actual part processing time takes 10-30 seconds once the acetone is up to temp. I gather the parts and process a batch at once. Lots more efficient that way. You can lengthen the process by lowering the acetone temp lower than 90c. At 60c it just about doubles the processing time so you have more control as to when to take it out.

---

If You Can Read, Thank A Teacher. If You Can Read It In English, Thank A Veteran That's what you do in a herd: you look out for each other. - Manny from Ice Age

New to 3D printing, not new to 3D or tinkering. LulzBot Taz 5 Generic Chinese 50w 300x500 Laser Cutter/Engraver (Ebay:171066211150) Corel X7, Photoshop CS6, Lightroom 4, Modo, Hexagon, Bryce, Poser

Each liquid evaporates permanently at ambient temperature Except maybe mercury, I dunno.

Edited 1 time(s). Last edit at 03/05/2015 08:49AM by Zavashier.

---

Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

Hours for cold polish? It takes 40 minutes, if you leave it without checking on the progress, dries overnight. Unused metal paint can, completely lined with doubled up paper towels, held in place with magnets, soaked with acetone right to the limit the paper towels can hold. ABS part set on a sheet of glass, and the metal paint can inverted and placed over the part. DO NOT check the part in the 40 minute time span or you will loose the vapor when you lift the can.

I've polished a 12" tall piece with a 5 gallon paint thinner can. Now if you'd be willing to boil up acetone in a 5 gallon container, that's all you!

Edited 1 time(s). Last edit at 03/05/2015 09:34AM by Dirty Steve.

Quote
Dirty Steve
Hours for cold polish? It takes 40 minutes, if you leave it without checking on the progress, dries overnight. Unused metal paint can, completely lined with doubled up paper towels, held in place with magnets, soaked with acetone right to the limit the paper towels can hold. ABS part set on a sheet of glass, and the metal paint can inverted and placed over the part. DO NOT check the part in the 40 minute time span or you will loose the vapor when you lift the can.

I've polished a 12" tall piece with a 5 gallon paint thinner can. Now if you'd be willing to boil up acetone in a 5 gallon container, that's all you!

Rofl! Who doesn't like a big bang I love seeing things blow up. Just don't like being close when it happens. O_O

See, I have been doing it the opposite way. Putting the part IN the container not putting the container OVER the part. That way I can look in the top to check progress (when I wasn't using a glass jar). The vapor is heavy so it will sink so little was lost by peeking. I must admit it can be a PITA getting the parts out though and I see your method of putting the pot over the part makes removal a snap. Maybe I wasn't using enough towels either. I think I used only 3, maybe 4 in a gallon paint can. I don't think I had them soaking dripping wet either. Can you estimate the quantity of acetone you are expending to do your container process? I am curious how it compares with the heating method.

I am using a counter top storage jar from walmart probably intended to store sugar or flour. Its opening is about 70mm square. Not positive on the height, but I would estimate 160mm. The jar body is bigger than the opening, probably 100mm square after if flairs out below the opening. I use 20-30cc of acetone per process period. I have a 10cc syringe that I either put two or three squirts from. Then I heat to 120c watching the jar. When I see condensation about 3/4 up the jar, I drop the pad to 90c and by the time its dropped, the jar is full. I can process quite a few batches of ABS before the acetone in the bottom is expended. If I only need to do a few parts, I only use 10cc but I usually save stuff up to run them as a batch.

---

If You Can Read, Thank A Teacher. If You Can Read It In English, Thank A Veteran That's what you do in a herd: you look out for each other. - Manny from Ice Age

New to 3D printing, not new to 3D or tinkering. LulzBot Taz 5 Generic Chinese 50w 300x500 Laser Cutter/Engraver (Ebay:171066211150) Corel X7, Photoshop CS6, Lightroom 4, Modo, Hexagon, Bryce, Poser

Going in from the top didn't give as good of results for me. I'd say maybe 2 or 3 ounces of acetone, varies with paper towel thickness.

I roached a pair of glass with hot vapor, and did some surface damage to my IR thermometer. Cold is much more workable for me and much less volatile.

Cold is also less aggressive with finer details. I've seen print sagging with hot.

Edited 3 time(s). Last edit at 03/05/2015 11:27AM by Dirty Steve.

I desagree with long exposure to vapours. It makes the part weak and modify the part dimension. I have a ventilated box regulated at 60°C. About 50sec are enough to smooth a part. Only the first wall is touched. Ventilation is a very important point IMHO. Actualy I don't use vapours any more. To me the best finish is tumbling + coating.

Edited 1 time(s). Last edit at 03/05/2015 12:41PM by Zavashier.

---

Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

A long slow exposure to acetone fumes at a low temperature (there has been a lot of low temperatures lately) seems to give added strength throughout the object with just a slight polish. If this is followed by a hotter exposure the surface finish can be very smooth. I think that acetone may weaken some types of ABS that have a large percentage of non acetone soluble plastics and or dyes. I think this is also the cause of the grey cast that is left on some ABS prints after acetone polishing.

Mike

Edited 1 time(s). Last edit at 03/05/2015 02:31PM by leadinglights.

True. Note I had some issues with some ABS filaments that leaved some white marks after vapours exposure. The charged ABS filaments known to have less wrapping issues have a tendency to leave those white marks.

---

Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)