Tuesday, February 26, 2013

 

Vapor Treating ABS RP parts




Treating ABS parts with acetone is almost as old as RepRap itself, but usually this has involved either dipping the part into liquid acetone, which causes white streaks in the parts, or brushing the acetone onto the part with a slurry mix, which can work very well but tends to be a messy process.

I have seen several setups out there, one by the Solidoodle Folks that involved a deep fryer, ice, tubing, and a candy thermometer, or completely passive systems that just used unheated acetone like TBuser of Makerbot did.

Unforgettably I am a horrible mixture of cheap and impatient, so I had to figure out a way to do this for little or no money out of pocket. To do this process you will need your RepRap's Heated Build Plate (must be able to reach 110C), a Glass Jar, Some Aluminum Foil, and a hanger to bend into a hook to get the parts out with.



First place your glass jar on the heated build plate and put a liberal amount of Acetone into the bottom of the jar (3-4mm deep). Initially you need to ramp up to 120C, especially if you have a heavy jar.  As the jar comes up to temp you will see the meniscus from the edge of the vapor cloud slowly creeping up the jar.  Once the vapor is to the top of the jar, turn the plate back down to 90C for the treatment.

Place your sheet of aluminum on your table, and your part on the sheet.  Lower the object into the vapor bath (very carefully, you don't want it falling off).  Leave the object in the acetone until you are happy with the amount of smoothing (the object continues to smooth out over the next few hours).

Once the parts are in process you can not touch them at all, the easiest way we have found to get the parts in and out of the jar is to fold aluminum foil  into a make shift table and use another smaller sheet of aluminum to act as a base for the part.  You can fish the parts out of the jar using a wire coat hanger bent into a make shift flat hook.



When done, carefully remove the object from the bath.  If you're done processing put a lid on the jar loosely and as the vapor cools it will condence back into liquid to be stored in your acetone jar again. Allow the part to sit for another ten minutes, the surface will be very squishy while the residual acetone dries off.

After some concerns were brought up regarding Acetone Vapor on heated surfaces in the home we decided to make the following video for reference:



This was done at Fablocker in NC, USA. By Austin Wilson and Neil Underwood (Spacexula)






Comments:
Hi all,

I love the idea, the result is clean, smooth and as stated in the video, looks quiet close to an injection molded squirrel...
nerveless, working on a daily basis with acetone, and dealing with acetone vapors, you have to be extremely careful, not with the fact it's highly flammable (you've covered this issue) but with the fact that acetone is an extremely powerful grease remover... and the trouble with this is that it can "clean" your lung in just a couple of sniffs... when I say "clean", I should say destroy any mucus that covers your lungs, eyeballs, throat (and there is plenty of it, and yes, you want to keep it ;) )... so be careful please ;)
so make sure that you do this technic outside or in an extremely well ventilated area and if you can, wear a proper gas mask (no, the paper one made for dust won't be efficient...)
thanks again for this very clever trick and H4ck safely ;)
 
Actually,

While acetone IS very flammable and it IS an excellent grease remover... it is NOT poisonous to the least and not dangerous to breath the vapors.

Just check the MAC (maximum allowable concentration) versus ethanol!!!

Two main reasons for this remarkable biocompatibility are that acetone is completely soluble in water (and thus is immediately diluted when it enters the body - and loses its solvent power) and that every cell in the human body produces (and gets rid of) tiny amounts of acetone as a result of metabolism.

So, be careful, but don't be afraid!
 
From Wikipedia- EPA EPCRA Delisting (1995). EPA removed acetone from the list of “toxic chemicals” maintained under Section 313 of the Emergency Planning and Community Right to Know Act (EPCRA). In making that decision, EPA conducted an extensive review of the available toxicity data on acetone and found that acetone "exhibits acute toxicity only at levels that greatly exceed releases and resultant exposures", and further that acetone "exhibits low toxicity in chronic studies".

I still use a respirator when getting close to the pot to get prints in and out, because if I'm doing enough of them, it'll give me a bit of a scratchy throat. So yes, it is a bit of an irritant, but not a significant health hazard.
 
Acetone is a Ketone, it permeates through the skin and enters the blood stream It is toxic to both the Liver and the Kidneys. It may not be Highly toxic but it is by no means, " NOT poisonous to the least"

For reliable data check the MSDS or Coshh sheets not someones interpretation thereof.

AL
 
I would think this also increases the strength and durability of the parts, since all of the small cracks and stress risers on the surface of the parts that are created when the object is built layer by later are now almost welded over.

This not only makes things look cool, it may well make 3D printed ABS parts functional in applications where they would not be in their raw printed state (even though the 0.1 mm layer height squirrel looked great to start with).

Well done!!!
 
Any idea what will happens with PLA plastic? Would really want to know, as have now Makerbot Replicator2 and it prints only PLA

Thank you in advance. And Great Job!
 
Any danger doing this directly below printed parts?
 
Today I did a test. Not having a heated bed at hand, we used a hair dryer. Excellent results too.

Thanks a lot Neil!!
 
Really nice results for me here!!!! Many thanks!!!!!!!!!!
 
PLA not working...
anyone Success this job ?
 
I tried it with nail polish remover and it didn't work i have to get a can of the real stuff.
 
I wonder if putting a thin layer of acetone in the bottom of a cheap rice cooker, and then putting the object on a little rack platform in the rice cooker would work.
 
Spacexula is back!! How about a Around the Community post??
 
Neil - that's really cool. I like the results a lot.

If you want a solvent for PLA diChloroMethane works well, but that is a lot nastier than acetone (which, as has been pointed out, you make inside yourself by lipolysis of fats when you run low on glycogen, such as when fasting). Treat diChloroMethane with much more care than you decide is appropriate for acetone. I usually work with it under shelter outdoors, which also helps reduce the fire risk too.
 
http://www.hse.gov.uk/pubns/wis19.pdf for HSE information on diChloroMethane

:)
 
Most impressive. I look forward to giving this a try. Thank you for the lesson!
 
Good and impressive! we ever dreaming have a high gloss finishing by 3D printing. By using this simple method, we can almost make it done.
thanks !
 
I look at this and the first thing that crosses my mind is why do it this as unsafe.

Safer is simple. Requires 2 jars not one.

One jar(jar1) is for the acetone and the object to be treated. This jar you have a lid with a pipe leading and into another jar(jar2) that has water in it. As the jar heats up the air/acetone leaving jar1 is filtered in jar2 by the water.

Next is since jar1 is now lidded you should get a more stable Vapor Treatment. Since there is a pressure release it cannot explode. Also due to the fact it sealed by the water even if it does start burning it has a very limited amount of O2 to burn with.

There is going to be issue of suck back from jar2 as the jar1 cools. So it might be valid to include 2 lines in so that once taken off heat the container can be opened to air. ideal of course is 2 one way valves of some form. Suck back might be what we want to happen as well. Coldish water from jar2 hitting model in jar1 to rapid set it.

The other thing I don't know if bubbling through one jar will be enough. Some of these using water to contain you need a few jars in series and at end blow some clean air through.

Basically the correct setup should be able to be done inside without any chance of opps I have fumes on floor waiting for ignition. The big problem with acetone vapour is the fact it sinks in air. So the vapour is going out over the top of jar and down to floor and if there is a basement under you down into basement. The fire problem will not be at jar it will be somewhere else after enough volume stacks up.

I don't see the extra cost as major 1 extra jar and some tubing at min. At max few extra jars some tubing and 2 one way valves.

diChloroMethane you have to swap the water with oil. Reason diChloroMethane does not dissolve willing in water. You will want positive pressure like from an compressor to blow remaining vapours into the oil that you can get away with not having with acetone even doing this with acetone is safer.

Same basic design should do both with relative safety.

My problem the cost to do safe and the cost to do unsafe is not much difference. So I don't get why using the less safe method.

I also suspect safe will give better results due to more stable Vapor ratios over the full jar height with the jar being closed. I don't have any ABS or diChloroMethane to try my self. Yes I have PLA and acetone.


 
Fantastic article and idea!
I was considering buying my first 3D printer and was concerned about the resolution.
So (even if 0.1 mm should always be better), does that mean 0,3 mm is "enough"?

Regarding oiaohm comment, I'd give it a try as I plan to play with kids with the 3D printer.

But with this Vapor Treating Solution: should I go with 0.1 or 0.3 mm resolution to get a result as close as injected plastic?

best from France
Fly
 
How does this go with corners? Do sharp corners (like 90 degree corners on a cube) stay sharp or do they round off?
 
REGARDING THE INCORRECT COMMENTS ON THE SAFETY OF ACETONE VAPORS POSTED HERE

FROM MSDS SHEET FOR ACETONE.....

PLEASE NOTE THAT "DATA NOT AVAILABLE" DOES NOT CORRELATE TO "SAFE"

TAKE APPROPRIATE PRECAUTIONS WHEN USING THIS MATERIAL

Potential Chronic Health Effects:
CARCINOGENIC EFFECTS: A4 (Not classifiable for human or animal.) by ACGIH. MUTAGENIC EFFECTS: Not available.
TERATOGENIC EFFECTS: Not available. DEVELOPMENTAL TOXICITY: Classified Reproductive system/toxin/female,
Reproductive system/toxin/male [SUSPECTED]. The substance is toxic to central nervous system (CNS). The substance may
be toxic to kidneys, the reproductive system, liver, skin. Repeated or prolonged exposure to the substance can produce target
organs damage.
 
Oh dear, as it occurs naturally in the body that means we are all going to die.

Oh, but wait, we all die anyway.
 
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