Finishing PLA prints

Stratasys parts finishing. The printed support structure is to die for.

Overall a very nice video.

[www.youtube.com]

I had to revise some of the photos on the previous page but unfortunately it's not allowed in this forum to update old posts. So for everyone who are interested in this topic please go to my thing page on Thingiverse to see the updated photos. Thanks.

DCM should not be taken lightly. It is nasty stuff.

MEK is an ABS solvent, and it does have some effect on PLA, but it's not a true "solvent" of PLA. Not going to give you the results you're looking for.

Unless you have access to a chem lab with a fume hood and a respirator, I wouldn't think of doing anything with DCM in a vapor form.

@maddox
I'm sure it could give you great results, but it's really not practical because of the health risk potential.

Some excerpts on DCM

"short-term exposures to high concentrations may cause mental confusion, lightheadedness, nausea, vomiting, and headache. Continued exposure may also cause eye and respiratory tract irritation. Exposure to methylene chloride may make symptoms of angina more severe. Skin exposure to liquid methylene chloride may cause irritation or chemical burns...

"The standard sets a permissible exposure limit (PEL) of 25 parts methylene chloride per million parts of air (ppm) as an eight-hour time-weighted average (TWA). This refers to the average exposure during an eight-hour period. Employers must use engineering and work practice controls to limit employee exposures. Respiratory protection must be used in addition if these controls are insufficient to reduce exposures to below the limits.

The action level for airborne methylene chloride is set at a concentration of 12.5 ppm, calculated as an eight-hour TWA. Reaching or exceeding the action level signals that employers must begin compliance activities such as exposure monitoring and medical surveillance. There is also a short-term exposure limit (STEL) of 125 ppm, as measured over a 15-minute period."

The short term exposure limit that's acceptable for workplaces is 125ppm over a 15 minute period.

125ppm is nothing.

Without a respirator/fume hood, it's simply unsafe to even think about using the stuff.

we have process barrels at work like that ummmmm wonder when i get my printer working i cud sneek a part in lol

any parts treated with DCM? images will be useful

Has anyone tried using a detailed hot air gun after sanding a PLA part? I've been thinking of giving it a try after reading a recent Make magazine.

After seeing this video [youtu.be] (desolved PLA support in caustic soda)

Maybe it is possible to use this method, just a little bit sorter to improve the surface

... I've 'smoothed' plastic surfaces with a solder-gun modified to a hot-air blower with a nozzle of maybe 0.5mm diameter and ceramic surfaces with a H2O2-torch with nozzle diameteres down to 0.1mm diameter.

It's possible, but you need a good part of experience and a steady hand

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I'll try and do a Dichloromethane print vapour refinish.

Not much vapour finishing experience, but I have lots of DCM and plenty of prints to test on.

It doesn't seem like anyone has actually done this and posted results anywhere?

I have used DCM lots on PLA for solvent welding and for a little spot finishing with a DCM soaked paintbrush with really fantastic results. Can't show photos of those actual prints unfortunately however.

Watch this space!

A few days ago I had some big PLA prints which needed smooth surfaces but they were much to big for dipping into the pure chemical, so I had to give DCM vapor finishing a try. My conclusion is that it works more or less the same as with acetone vaporizing. Not much DCM is needed. Pour some water into your container (I use a stainless steel pot with lid) and then add a small amount of DCM. The steam increases the strength of the DCM and makes the smoothing process faster. Unfortunately I can't show any photos of the vaporized parts as I don't have these parts any longer but the surfaces looked similar as with acetone. Smooth but not so shiny (more matte). But no more visible layer lines! I liked it.

just seach for DCM in thingiverse [www.thingiverse.com] , but have you read [en.wikipedia.org] ? if you have plany of DCM hopefully

I've just done some testing with THF on various PLA filaments (5 total).

3 of them became gummy and started delaminating after vapour treating for half an hour to one hour.
1 was completely unaffected.
1 reacted *exactly* like ABS does to acetone.

Conclusion: not all PLA is born the same and THF does work, just not with all PLA.
I've sent an e-mail to the seller i bought the THF dissolving PLA from, maybe i find out who made it and what the composition is.

As a sidenote, i've tried MEK on multiple PLA samples. It does next to nothing.
Very long soaks (day or two) make PLA semi-permanently elastic. You can stretch a piece of 3mm filament to almost 150% its length.

Also, i've had PLA once that could be smoothed with hot acetone vapours.
If i recall correctly, it was Faberdashery's forest green. Figured out it reacts to acetone purely by accident (spill).

Edited 1 time(s). Last edit at 07/22/2013 11:51PM by orcinus.

Turns out the filament THF works on is 4032. All the others were 4042/4043.

Just ordered some Dichloromethane to give it a go. Iv used acetone vapour with ABS with great results just reallly hoping this works for PLA as i hate ABS in so many ways.

DCM still gives me the shivers...
As much as i'd like to try it (according to everyone's experiences, "it just works"), that MSDS sheet scares the hell out of me.

I'm not too happy about THF either.

I've kept silent until now about the acetone bath for ABS but you guys are entering extremely dangerous territory now. This is insanity. Working with these chemicals outside of a laboratory without proper safety equipment is just plain foolish. Have you read the MSDS for this stuff? Do you know what an MSDS is? How about this..do you know how much more dangerous this stuff can be when it is heated up? An MSDS won't even tell you that.

Are you even using gloves? Have you checked a glove material compatibility chart to make sure that the gloves you are using is actually keeping this stuff off of your skin?

Are you using safety glasses? Do you know how much worse this stuff can damage your skin and eyes when it is at high temperatures?

I'm a chemist and have worked in research laboratories for the last 25 years. I would never work with any of these solvents outside of a hood and without proper PPE. You are risking yourself, your family and your community by doing these experiments at home.

Just stop!

If you are really interested in smooth prints then put your efforts into designing some of the other types of 3d printers for home use that can make smooth prints.

KDog

calcetin Wrote:
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> Tetrahydrofuran is probably the safest of the
> chemicals mentioned here. The others are
> carcinogenic or suspected to be.

THF is a mammalian mutagen and probable teratogen.
So no, not exactly safe, although definitely safer than DCM.

@Mister worrysome above - you *do* know that most of these solvents were used and still are used in lots of off the shelf products in nowhere near negligible concentrations, right? Carburetor cleaners, paint thinners and strippers, glues and cements... They all contain them and are used with *much much less* precautions and with nearly no consciousness of the dangers involved *on daily basis*.

Do you have a habit of knocking on people's doors and screaming at them to stop using those too?

Thought you don't.
I know you mean well, but rest assured (or read some of the previous threads) - pretty much everyone is informed as far as dangers involved are concerned. If they choose to continue using them, it's on them.

I realize that these solvents are used in some commonly available products. That does not make them safe. Google methylene chloride (DCM) accidents and see how many people have died working with some of these products. Keep in mind that these are products that only "contain" DCM, not the concentrated product.

THF can form explosive peroxides over time, just like ether. So, if you do try it, keep it in mind when you finish with your experiments and put it on your garage shelf to sit for the next ten years.

I'm sure that folks can use this stuff safely if they read up on it and think about what they are doing.

KDog

BTW...I do talk to my neighbors about solvent safety if I smell it when walking by their house or see them doing something silly with it. Why wouldn't I?

Enlightx Wrote:
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> Just ordered some Dichloromethane to give it a go.
> Iv used acetone vapour with ABS with great
> results just reallly hoping this works for PLA as
> i hate ABS in so many ways.


Just curious why do you hate ABS I think it's a much better material I have great results printing it obviously it can't be because of the fumes if you bed temp is at least 110 C and you have at least a makeshift enclosure does not warp or crack and with acetone and a coat of clear lacquer finish which also melts the service a little will give it a great finish

dont like ABS because

1. Smells bad and i print in a small room with no much ventilation
2. it lurves the warp factor
3. Its hard to buy quality ABS unlike PLA i can order faberdashery and i have not 1 issue with the plastic
4. higher temps = more power so costs more to print.


its just general hassle i think i dare say if i worked hard to get ABS printing nice etc it would be great and i dare say i could hunt around for a decent ABS supplier but the thing is currently ABS has no benefit for me other then vapor smoothing i would say PLA will have something similar in the coming years with PLA now being taken up a lot with the lower end printers.

I did get some Dichloromethane and yes it does disolve PLA very well. I currently use it to clear PLA from hobbed bolts. does not work so well for vapour smoothing. it will vapour at around 60C quite easy but does not attack the pla externally enough to smooth it out like acetone. it tends to just made the print more flexable.

worst thign is Dichloromethane is a scary chemical it does not smell nasty like acetone so you tend to not be as carefull which is a bad bad thing. also you dont notice the smell when using and with it turning to vapour so low i can see how there are massive warning for people using this stuff in a factory environment.

jk25. Looks like your images are no longer there. I would of like to see the results.
Is there another link?

i'm thinking of doing the same - to use DCM to improve the part appearance.
what grade of DCM did you use and what are the safety precautions to take?

Disregard.

Edited 1 time(s). Last edit at 10/13/2014 02:25AM by ShaneH.

Before going to far into considering DCM for PLA smoothing, consider that this is a very old thread and that the process has been pretty much abandoned in favor of using the solvent Ethyl Acetate, which is a much much safer chemical than any that are discussed in this thread.

Here's a link to the newer thread.

There are reasons that it's not the best idea to resurrect dead threads, guys.

Edited 1 time(s). Last edit at 10/13/2014 03:11PM by Feign.

Ditto. Ethyl acetate FTW.

Quote
Feign
Before going to far into considering DCM for PLA smoothing, consider that this is a very old thread and that the process has been pretty much abandoned in favor of using the solvent Ethyl Acetate, which is a much much safer chemical than any that are discussed in this thread.

Here's a link to the newer thread.

There are reasons that it's not the best idea to resurrect dead threads, guys.

2 recommendations. Start with spot putty (used for automotive paint to fill scratches and small dents), sand as best you can. Then spray with filler primer (very thick heavy primer that is applied in a very heavy coat and smoothes out the surface filling in small scratches as it goes) then paint. This of course works for ABS as well. Yes it takes time and effort but this is the method used by many model and prop makers.

ive heard ethyl acetate works well for pla. its safe and non toxic as well. it is used as an artificial flavoring in pear drops(candy). it is used as a vapor wash like acetone and abs. im going to be trying it out myself here soon. heres the wikipedia link if you wanna check it out: [en.m.wikipedia.org]. ive though of tumbling but havent tried it yet i have a tumbler and im going to try that out as soon as i get some finer medium.

Edited 1 time(s). Last edit at 03/02/2015 07:52PM by queenannesrevenge.

Old washing machine with the interior completely lined, covering all the holes. 3/4 full of sand, throw in your parts - I've seen this used in Russia as both a cement mixer and abrasive sander

+1 for the mecanical solution instead of chemical. I use tumbler then varnish (or different coatings).

Edited 1 time(s). Last edit at 03/04/2015 07:24AM by Zavashier.

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I've seen the other post about this and I have tried "MEK Substitute" and it will not do anything to any of the PLA I have. Same exact container as pictured and I can store the stuff in my prints.

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