Proper disposal of isopropyl alcohol

Where is the proper place to dispose of the isopropyl once it’s turned completely murky? I’ve not seen any mention of this anywhere, which is quite concerning. How is nobody talking about this? Is everyone flushing their dissolved resin down the toilet? I know there’s hazardous materials disposal centers, but even in a big city like LA, their hours are really strange and hard to conform to, and when they ask what the contents are and I say “photopolymer resin”, they give me a nasty “WTF??” look.

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I had this problem recently, i asked the community for advice. I tested their various solution. So, put the dirty isopropyl under the sun, so the resin in it become solid. Then get an empy jellycan and cut open huge cola bottle at the bottom, put coffee filter at the opening (with cable tie) and pour isopropyl down. Pour slowly, wait for the filter to slowly filter , pause and wait. Pour the rest of isopropyl.
Clean the container and pour the filtered isopropyl back to container and check. If it is not good, filter again with a new coffee filter. Some alcohol lost, top off with new isopropyl.
I started with paint filter, but it is no good, only coffee filter works. Remember you must expose the isopropyl with UV first.

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This has been discussed before in a quite a few threads, including one I posted on.

In my case, I put the IPA container on the balcony for a few days to solidify the gunk, and it does, but not completely, it will always remain like a jelly, even of you take it completely out of the container and exposed it directly in the sun. There’s simply too much alcohol content in that mix for it to become rock hard, and it can’t evaporate since the alcohol is trapped inside the gel.

I eventually put the stuff in a 1 gallon Freezer zip-lock bag and dumped it in the trash. It may not be the proper way of doing this, but at least it didn’t end up in a sewer.

Most communities have hazardous waste recycling events where you can take used motor oil, etc. If you find one of those you can ask if they take IPA.

In my case my company already has a waste disposal service which picks up our Acetone, used oil, ozzyjuice and waste mop water from our warehouse, so we just added the IPA to the list.

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it is a waste of money to dispose them just because it is a little dirty. It can get dirty real quick. I reuse them by filtering them through coffee filter. It can be real expensive if i have to replace them every time it get dirty.

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How much does IPA cost where you live?

Here, in California, 1 quart (~1L) costs $4. SO I don’t think it’s worth bothering with trying to clean it up. Not just that, but even though you filter out the particulates, the dissolved resin has already mixed with the IPA, giving the IPA an oily feeling that leaves a film behind.

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4.50 Euro per bottle, but i keep having small particle of resin which i can see by my eyes, in less than 1 week in the container. So these small little speck of resin have to remove, if i do not do that, the next time i use another color resin. I see the print with small tiny particle with different color on it.
The oily feeling of the IPA is true, i feel that too, it cannot be removed by coffee filter. I guess i have to replace my IPA after a few months. But week to week, i need to clean my container of IPA with coffee filter.

That’s why I use two baths. One for rough cleaning, which leaves the oily stuff. And the other one to get nice dry pieces. My cleaning agents seem to last much longer this way.

If the gel is broken up the alcohol will eventually all evaporate and the resin will solidify to crumbly lumps. It is also possible to wash out the alcohol with water.

Me too, but i can see both baths contains small speck of resin after a few days of use. My baths are next to the windows.

My company recently purchased a 5 gallon drum of 99% IP From uline. $145 seems expensive based on your quote of $4/qt. however this is 99% IPA. My guess is that you are buying 70%?

For the record From Jun - Sept last year we bought 1 gallon sized 91% IPA. In Sept we bought the 5gal mentioned above and just now we are needing to re-order.

No, it’s 91% for $4. 70% can be had for as little as $3.00. Here are the prices today at the Walgreens store.

The regular price at my local Wlagreens for a bottle of 91% IPA is usually $4, but it looks like this week I can buy one and get one for 1/2 price, so I can get two bottle for $6.

Yeah, I would have thought buying bulk from a place like uline would have been cheaper…guess not.

Several topics in this thread.

  1. I use the two tanks provided by Formlabs and it works well for me. When I need to replace the first tank, I empty it and poor the cleaner tank into the dirty tank and add fresh alcohol to both.
  2. I used to buy 90% at Walgreens, they looked at me kind of funny when I would approach the register with .6 bottles. I now by galllon cans at Home Depot. It’s not not 90% but works fine and is cheaper than the good price at walgreens and Home Depot always has it in the paint department.
  3. I don’t have a good solution to share for this one. I will say mine does not go down the drain. I use. An evaporation approach. I have toyed with using kitty litter and then tossing it but have not gotten around to trying it. Hazardous disposal drop off location is the obvious choice but not very convenient here in my large city. A sand and activated carbon filter might be an option if you want to try to reuse…just a thought. Another option could be a still…but don’t jerry rig one and do keep a fire extinguisher close.
    This might work…

I just did some more checking and diatomaceous earpth would work for absorption and disposal. Here is a product from Canada that addresses alcohol.

I think you can buy bags of diatomaceous earth in the garden center at a place like Home Depot.

Amazon has 99% IPA 16 oz for $2.35.
12 pack for $19.99 or only $1.66 each.
Thats $13.32 per gallon (Free shipping if you have Prime).

Great find, thanks

Hi sloh,

it sounds like you’re a german guy (or even close to).
We purchased as company mostly 10L of IPA online.
( )

30€ for 10L are a pretty good price unless you don’t want to get 50L, like we do now.

Cheers Tim

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