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Vapor Smoothing PLA

Posted by PrintedSolid 
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PrintedSolid
Vapor Smoothing PLA
March 25, 2014 09:18PM
Hello,
I stumbled across a solvent that works reasonably well for vapor polishing PLA based materials and quite well for vapor polishing PET based materials. Ethyl Acetate (Sold as MEK Substitute in hardware stores).
Here is a blog post on my results with PLA, colorFabb PLA/PHA, colorFabb woodfill, madesolid PET+, and colorFabb XT. http://www.printedsolid.com/smoothpla/
Note that this was my second effort trying this process out, so I don't really have the settings dialed in, but it's certainly an encouraging result. The earlier experiment also included t-glase which smoothed similar to the XT.

If you give it a shot and further refine the process, I'd love to hear your results.

Matthew Gorton
US Reseller for colorFabb filaments
3D Printing and Design services
[www.printedsolid.com]
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runninfarmer
Re: Vapor Smoothing PLA
March 25, 2014 10:14PM
Nice job with the research and experiments. It does make sense chemically since EA is an ester and PLA is a polyester. I was interested in trying out fatty methyl esters in the same way, which are what Biodiesel is. Biodiesel is also a much stronger solvent, but much higher boiling point, so it may not work as well to get it into a usable vapor form for smoothing PLA.

Edited 3 time(s). Last edit at 03/25/2014 10:18PM by runninfarmer.
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waitaki
Re: Vapor Smoothing PLA
March 26, 2014 03:45AM
Be careful with MEK

_______________________________________
Waitaki 3D Printer
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CaptainObvious
Re: Vapor Smoothing PLA
March 26, 2014 09:10AM
Quote
waitaki
Be careful with MEK

It's not MEK, it's Ethyl Acetate, a quick look in Wikipedia says it has low toxicity, it's even present in some foods.

It does seem like a great discovery, it should work really nice in prints with layers of less than 0.2mm thickness.
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CaptainObvious
Re: Vapor Smoothing PLA
March 26, 2014 10:44AM
Oh!, the penny dropped! grinning smiley

There's another great use for this stuff, to clean up nozzles used with PLA! Or jammed hot ends for that matter.
Now I just need to see if they have it at the hardware store...
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gmh39
Re: Vapor Smoothing PLA
March 26, 2014 04:09PM
Is heat absolutely needed for this, or is it just used to expedite the process?

greghoge.com

HUGE 3D PRINTER PARTS SALE!!!
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PrintedSolid
Re: Vapor Smoothing PLA
March 26, 2014 05:19PM
@captainobvious, thanks for clearing that up. I've heard that same response from a few others. Yes, MEK is dangerous, but MEK wasn't used in this experiment. Although there may be MEK in the acrylic cement that inspired my experiment.

I'm not sure what the mechanism is that is causing the smoothing. It is different than ABS where the ABS is going into solution. I do think that vapor is needed for PLA, but not for PET. (check this earlier experiment I did with PET http://www.printedsolid.com/vapor-polishing-colorfabb-xt/)
So, to do this with PLA, you do need at lease some heat.

You get quite a different effect if you just dip the PLA in the EA. It becomes a little rubbery and degrades. It doesn't dissolve.

Aside from the few experiments I've done, it's all speculation on my end and there is plenty of room for experimentation and process development. I'll keep the blog updated as I learn more and would be glad to link to others who expand on the idea.
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cozmicray
Re: Vapor Smoothing PLA
March 27, 2014 12:08PM
MEK is NOT ethyl acetate.

Which one should be used to smooth PLA?
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PrintedSolid
Re: Vapor Smoothing PLA
March 27, 2014 05:15PM
Quote
cozmicray
MEK is NOT ethyl acetate.

Which one should be used to smooth PLA?

The 'MEK Substitute' shown in the post is Ethyl Acetate. It is sold in the hardware store in the paint section near the acetone.

That is what I used for the smoothing.
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lions3
Re: Vapor Smoothing PLA
March 28, 2014 09:08AM
what temp did you heat the ethyl acetate up too? How long did you leave the PLA parts in the heated chamber (lol, deep fryer).

This sounds like something that might work well for me in the garage. I wonder if you could use an electric hotplate and some kind of jar as you're vapor chamber.
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PrintedSolid
Re: Vapor Smoothing PLA
March 28, 2014 06:49PM
I set it to 200 on the dial until the vapor hits the top of the part, then I turn off the heat and remove the part. It takes less than 30 seconds.
Acetone vapor is lighter than the EA vapor, so this process doesn't work as well for taller parts as acetone does with ABS.
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iquizzle
Re: Vapor Smoothing PLA
March 29, 2014 05:33PM
The MSDS for MEK is 1-3-0, while the MSDS for Ethyl Acetate is 2-4-0 according to wikipedia. Are you really sure it's safer? MSDS would suggest otherwise.
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nicklogan
Re: Vapor Smoothing PLA
April 01, 2014 12:19PM
As waitaki said, be careful with MEK - if you get it in your eyes it will ruin your corneas - there is no antidote.
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DonaldJ
Re: Vapor Smoothing PLA
April 06, 2014 04:50AM
Quote
iquizzle
The MSDS for MEK is 1-3-0, while the MSDS for Ethyl Acetate is 2-4-0 according to wikipedia. Are you really sure it's safer? MSDS would suggest otherwise.

Also from the Wikipedia entry:

Uses

Ethyl acetate is used primarily as a solvent and diluent, being favored because of its low cost, low toxicity, and agreeable odor. For example, it is commonly used to clean circuit boards and in some nail varnish removers (acetone and acetonitrile are also used). Coffee beans and tea leaves are decaffeinated with this solvent.[3] It is also used in paints as an activator or hardener.[citation needed] Ethyl acetate is present in confectionery, perfumes, and fruits. In perfumes, it evaporates quickly, leaving only the scent of the perfume on the skin.

[en.wikipedia.org]

Seems safe enough for me, but I'll read the label carefully...
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LdyMox
Re: Vapor Smoothing PLA
June 24, 2014 02:46PM
I have been playing with using M.E.K Substitue for Vapor polishing PLA with some suscess after reading Printed Solid's page. (I posted a few times on the Solidoodle Forum about it.. [www.soliforum.com] )

But anyways. I got much the same results as PrintedSolid once I got the timing down. I can probably do more tweeks to get the timing even better.



Edited 1 time(s). Last edit at 06/25/2014 04:17PM by LdyMox.
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BackEMF
Re: Vapor Smoothing PLA
August 03, 2014 03:00PM
Does this Ethyl Acetate also soften the PLA?

And if yes, does the PLA stay soft?
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PrintedSolid
Re: Vapor Smoothing PLA
August 03, 2014 03:40PM
It doesn't really soften significantly in the vapor, but does if you soak it.
It softens the and makes it rubbery. Unfortunately, it also swells and delaminates it and the change isn't permanent sad smiley
PET gets nice and rubbery after an acetone vapor polish without any significant swelling, however that also goes away.
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BackEMF
Re: Vapor Smoothing PLA
August 03, 2014 06:00PM
Hmm ok, then i have to keep my eyes open for the next chemical.
Would be nice to know what chemical makes flexible PLA flex.

I try to find a solution to keep just one type of plastic (PLA) in the machine and still be able to create Gaskets and Rubbery wheels occasionally. The few times i actually want to print something flexible isn't really worth the hassle of buying and storing flex PLA nor the hassle of changing the filament for that one occasional print. I also seen someone use carburetor cleaner though thas doesn't seem a very healthy option.

Unfortunately chemicals arn't my strongest subject so i'll just have to be more patient :-)

Thanks for the deeper insight! Looks like it is also important to find the right temperature where the PLA fuses best, that might improve the delamination issue, I'll try to find Ethyl Acetate and give it a try.
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nophead
Re: Vapor Smoothing PLA
August 03, 2014 07:11PM
It de-laminates because the outside surface swells quite dramatically but the inside stays the same size, so it sort of rips itself apart. I put an android in it and its chest exploded like something out of Alien. After that it didn't change much even after days. So it doesn't completely dissolve like ABS in acetone. Or if it does it needs a lot more solvent to plastic ratio.

[www.hydraraptor.blogspot.com]
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BackEMF
Re: Vapor Smoothing PLA
August 03, 2014 08:13PM
I see, would it make a difference when a n object is thin (like a timing belt or a gasket?)

And / or if the Ethyl is diluted in water or another substance so that it soaks more slowly into the material?

Wild guesses, just sharing my thoughts...

I have dropped a piece of PLA in some vinegar to see if that does anything maybe just silly though after reading the Ethyl wiki page I just got curious. grinning smiley

"Excessive amounts of ethyl acetate are considered a wine fault." and... "which leaves the wine with a sharp vinegar-like taste" this triggered my curiosity.

If this happens to do anything spectacular i sure will report back on it. smiling smiley
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Feign
Re: Vapor Smoothing PLA
August 13, 2014 09:59AM
I'm a bit curious about this, especially the vinegar test. While vinegar has a little bit of ethyl acetate, it's mostly ascetic acid... But from what I understand, it's the acetone in it that does the magic, so there's reason for it to be feasible.

If PLA can be smoothed with old-fashioned vinegar then I think we'd have a winner. grinning smiley
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oklok
Re: Vapor Smoothing PLA
August 13, 2014 11:51AM
Hi,

U got that right acetone do the the magic, mostly of it property to serves as an important solvent.
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BackEMF
Re: Vapor Smoothing PLA
August 14, 2014 02:41PM
Thanks for the reminder, I almost forgot to check.

I just took the sample out of the vinegar and the only thing that seems to have changed is the color. The color is a bit more vibrant.

The PLA feels a bit more flexible but it can also be messing with my mind a bit. So lets just say it doesn't really work for what I had in mind. Still I put the sample back in the vinegar and lets see if a few more days will make a difference, I doubt it but since it has been sitting there for 10 days already i might as well leave it 10 more and then make that the final result.

If anyone has other 'safe fluids' to test with then why not give it a try.

Far as I understood acetone only works for ABS but not for PLA

And to be clear i'm looking for a way to soften PLA to make it rubbery so that i can print gaskets from normal PLA and then sotfen it to make it flexible so excuse me if I caused any confusion on this thread about smoothing PLA.
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tjb1
Re: Vapor Smoothing PLA
August 14, 2014 02:46PM
Quote
BackEMF
Thanks for the reminder, I almost forgot to check.

I just took the sample out of the vinegar and the only thing that seems to have changed is the color. The color is a bit more vibrant.

The PLA feels a bit more flexible but it can also be messing with my mind a bit. So lets just say it doesn't really work for what I had in mind. Still I put the sample back in the vinegar and lets see if a few more days will make a difference, I doubt it but since it has been sitting there for 10 days already i might as well leave it 10 more and then make that the final result.

If anyone has other 'safe fluids' to test with then why not give it a try.

Far as I understood acetone only works for ABS but not for PLA

And to be clear i'm looking for a way to soften PLA to make it rubbery so that i can print gaskets from normal PLA and then sotfen it to make it flexible so excuse me if I caused any confusion on this thread about smoothing PLA.

There is a youtube video showing how to make PLA flexible, it may work for you. I think they were using Carbureator Cleaner or Starting Fluid to do it but I can't remember right now.
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BackEMF
Re: Vapor Smoothing PLA
August 15, 2014 05:11PM
Yes i also came across that, but carb cleaner isn't all that healthy.

for instance [www.ehow.com] says:
"The toxicity of a carburetor cleaner's main ingredients, by themselves, makes this cocktail a hazardous material, requiring educated and careful use."

So don't use it on printed toys that can end up in a child's mouth. I'm NOT planning to use it on toys myself, I just try to find a non toxic alternative.

Going to have a look if Starting fluid is the same thing with another name or something different.

Thanks
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PrintedSolid
Re: Vapor Smoothing PLA
August 15, 2014 07:03PM
I've also tried the carb cleaner to rubberize parts. It definitely works. You lose some color though.
And definitely be careful.
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BackEMF
Re: Vapor Smoothing PLA
August 28, 2014 07:52PM
And another 2 weeks later:

Vinegar definetly softens the PLA, but after a month it's only a little soft (just not brittle anymore) but i still won't call it flexible. And it's not worth waiting a month for. :-)


In the bookstore I looked into a few books on Polylacticacid and came across something called THD. That was mentioned as an organic solvent. Back at home i asked Google about THD but big G doesn't seem to know it. :-) The nearest hit is THF [en.wikipedia.org] although i'm not sure if this is the same thing.
But from the info in the books this THD should be the solvent that reacts best with PLA.

So:

If you happen to have this stuff (and if it is safe to use) then please give it a try for smoothing.

Edited 1 time(s). Last edit at 08/28/2014 07:53PM by BackEMF.
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MrDoctorDIV
Re: Vapor Smoothing PLA
August 28, 2014 09:41PM
People have had the best luck with THF, using it similar to Acetone on ABS.

Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus
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BackEMF
Re: Vapor Smoothing PLA
August 29, 2014 12:06PM
Thanks! Nice article BTW.

Does this THF also make the PLA flexible or does it become hard and brittle again after the treatment?
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MrBaz
Re: Vapor Smoothing PLA
August 30, 2014 10:06PM
Apparently, the Weld-On product line works just like acetone for abs. I believe weld-on #5 is pretty fluid and could be used for cold-vapor smoothing.
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