Recycling IPA

[mu26aeh]

Anyone here that cleans prints in 91% alcohol, do you recycle your IPA ?  I watched a few YT videos and gave it a try.  Set bottles in the sun, filtered out the larger concentrations, set out again.  Filtered thru paper towels and coffee filters.  Appeared to be pretty clear.  Filled the wash station back up and set my build plate to clean off some resin while at work.  When I came back, I pulled build plate out and it was coated with resin.  Something doesn't add up.

If you're succeeding at recycling IPA, what's your go to method ?

[ednadolski]

Tried a few times, but the alcohol turned a nasty yellowish color and gave a horrible chemical smell.  I have no idea what is in it.

Ed

[peteski]

While no specific experience with filtering out resin, I want to mention that whenever the alcohol is exposed to ambient air, the alcohol evaporates at faster rate then the water in the mix. It also absorbs water from the ambient air (if you live in high humidity climate).  Basically, it will slowly loose strength (the percentage of alcohol to water will decrease).  The weaker it is, the less effective it will be at its job.

[Chris333]

I've tried a bunch of times and if you could some how get it to work it would not be worth the $3 bucks you saved.

It takes so much effort, time, and many different containers only to be left with stuff that is not as strong.

[mu26aeh]

I figure at least a decent prewash, use new/fresher alcohol for final.  But don't want to put items in and get more resin on the item afterwards

[John]

I figure at least a decent prewash, use new/fresher alcohol for final.  But don't want to put items in and get more resin on the item afterwards

For the first wash - you could use simple green and scrub with a tooth brush, then final rinse in cleaner alcohol.   Other people have used denatured alcohol - but I don't like to keep that in the basement. 

Another option is the water wash resins .. but don't pour it down the drain until after you set it out in the sun for a while to cure the floating resins ..

[JeffB]

Is buying/replacing your used IPA that much of a hobby/household budget buster that you're forced to try to recycle it?  If so, maybe 3D printing is not for you.

That said, I can understand if you're doing it for environmental reasons.

FWIW...  IPA is cheaper in bulk (99% IPA in gallons off Amazon).

Jeff

[John]

Is buying/replacing your used IPA that much of a hobby/household budget buster that you're forced to try to recycle it?

Fair question - but it is an expense that you might want to minimize. 

Wal-Mart sells Equate 91% 32 Fl OZ for $3.98 -  ($0.12 fl oz)  - advantage it is easy to get.

they also have 1 gallon 99% for $29.99 ($0.23 per fl ounce) order on line.

Amazon is similar - 23-25 cents per fl in gallon quantities

So depending on how much printing you do - it adds up

I personally haven't had too many issues with dirty IPA - as long as you scrub and then the final clean is in relatively clean alcohol ..

[JeffB]

Fair question - but it is an expense that you might want to minimize. 

Wal-Mart sells Equate 91% 32 Fl OZ for $3.98 -  ($0.12 fl oz)  - advantage it is easy to get.

they also have 1 gallon 99% for $29.99 ($0.23 per fl ounce) order on line.

Amazon is similar - 23-25 cents per fl in gallon quantities

So depending on how much printing you do - it adds up

I personally haven't had too many issues with dirty IPA - as long as you scrub and then the final clean is in relatively clean alcohol ..

4 gallons of 91% IPA on Amazon for $69.05, which is $0.13 per fl oz.  Not quite as cheap as Walmart's 32 fl oz bottle, but close enough and you get it all in one shot.  Not through multiple trips to Walwart.

I do get wanting to save money...  Also get (and appreciate/respect) conserving resources.

Jeff

[peteski]

Other people have used denatured alcohol - but I don't like to keep that in the basement. 

I'm curious what is the reason for specifically disliking denatured alcohol?  91% IPA is just as hazardous (flammable).

[JeffB]

I'm curious what is the reason for specifically disliking denatured alcohol?  91% IPA is just as hazardous (flammable).

Not necessarily relevant to your comment, but I'll add that denatured alcohol is more effective for cleaning prints...  It just smells a bit more (IMO). 

Jeff

[C855B]

I recycle 99% IPA, though in just the handling the hygroscopic nature of pure alcohol reduces it to 90-95%. I use an AnyCubic wash and cure machine as my "scrubbing" process.

What I do is two-step. I let the solids settle for a day or so in the wash tank, then carefully pour that off into a 1-gallon bottle, where it settles again. Then I pour that into 1-quart bottles through a commercial-size coffee filter in a large funnel. The filter clogs pretty quickly; I seem to get barely one quart per filter.

Now I don't do a lot of printing, so the time to settle out the solids may not work for everybody. I'm also starting to question all the handling involved; there have been spills.

[Lemosteam]

I use a three step wash process, and I mainly do small parts (no big shells, etc.)

This will sound like a cleaning post but its not as you will see.

Note that I effing HATE resin.

One sealed container of used 99% IPA (maybe 20 fluid oz).

One sealed container of clean(er) 99% IPA (maybe 20 fluid oz).

One partially filled on the fly ultrasonic cleaner using Acetone.

After draining excess resin into the vat, I pop the parts off the build plate and place them into the first container and let them soak for a few minutes.  When all the parts are in the bath, I use an ultrasonic brush to clean the parts, immediately placing them into the second bath, where I rinse and maybe a little more brushing.

Then I place the parts in a drain position onto a folded paper towel.

Then I place the part un the UC and fill to just above the parts with the Acetone and run the UC for a very short period.

When done, I inspect them for any residual resin, and maybe brush them with the UC brush again.

Sometimes I give them a manual few second swish in Acetone in a third vat. After that I place them on the towel to dry again.  I filter the acetone right back into its container after use (much evaporates though) but there is always something left to dump.

Usually I do not have to rinse them in cold water, but sometimes I do with very thin walls or cross sections.

Periodically I filter the dirty IPA and put it back in the first tub, When it gets so cloudy I cannot see the parts, I will dump the contents into the hardening bottle for waste.  As it settles I find that I can sometimes filter the IPA from that bottle and it never comes clean, so I will put it back in tub 1.  If it is still to dirty, I will just let it evaporate as the resin hardens.  Then I will take bath 2 and empty it into bath one using a filter to become my new "dirty" IPA.

Then I put fresh IPA into bath 2 and continue this multi-stage IPA degradation process until evaporation and discard of hardened resin.  What the right word, distillation?

I find that this cleaning process keeps bath 2 clean for a long time, as bath one removes most of the resin and rarely leaves residue in the acetone filter.

I have also found that I only end up using my wash and cure for curing, so that stays really clean too.

For what its worth, I don't do that much printing and the sealed containers keep the IPA really well, not so much the Acetone.

[John]

I recycle 99% IPA, though in just the handling the hygroscopic nature of pure alcohol reduces it to 90-95%. I use an AnyCubic wash and cure machine as my "scrubbing" process.

What I do is two-step. I let the solids settle for a day or so in the wash tank, then carefully pour that off into a 1-gallon bottle, where it settles again. Then I pour that into 1-quart bottles through a commercial-size coffee filter in a large funnel. The filter clogs pretty quickly; I seem to get barely one quart per filter.

Now I don't do a lot of printing, so the time to settle out the solids may not work for everybody. I'm also starting to question all the handling involved; there have been spills.

Thats similiar to what I do .. I'm also not a prolific printer .  all my models if for personal use (mostly)

[John]

Not necessarily relevant to your comment, but I'll add that denatured alcohol is more effective for cleaning prints...  It just smells a bit more (IMO). 

Jeff

Jeff - My experience as well ..

Peteski -- The smell is much stronger, and my cleanup station is near the gas furnace, so I only use it in the spring / summer when I can use it with the basement door open for ventilation (the door is also next to the printer area)