Proper disposal of dirty IPA as far as EPA or hazardous material requirements

Does anyone know of proper disposal of dirty IPA as far as EPA or hazardous material requirements? Or just general information on proper disposal of the spent IPA

pour it into a cheap aluminum tray, $1 Store kind, and set out in the sun to harden. That can then be just dumped in regular trash as it’s basic plastic.

Thanks Walter. I assume putting a UV lamp over the bucket or tray holding the dirty IPA will work as well? This is being used in a commercial application so I can’t leave it outside in the parking lot.
Thanks again

The problem is that it never actually solidifies, you’ll end up with a Jello like substance.

I’ve gone through this a few times already. I’ve taken the vat and left in the sun for 2 weeks, and it still didn’t harden completely. It ended up as a gelatinous block, which I then broke up and put into Zip lock bags and tossed.

I suppose you could break it up in small pieces and see if they’ll cure all they way through, but I ran out of patience, so I just tossed it.

It will harden if you keep breaking up the slab of uncured resin to release the IPA. One the resin get to be semi-hard you can also wash the IPA out of it with water.

It’s actually OK to pour IPA down the drain, mixed with water. Dirty IPA has uncured resin in solution in the IPA but the resin will cure and precipitate out of the IPA with enough UV exposure. Decant the IPA through a paper towel (to catch blobs that’d plug the drain up) and down the drain with the faucet running and then throw the paper towel with the resin remains in the trash.

While it is probably OK to pour SMALL amounts of isopropyl alcohol down the drain (diluted in water), it should be treated as hazardous waste. Some counties have pickup service - you can place it outside of your house or business. Other places you may need to mark it properly and drop it off at a facility.

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I would suggest that the amount of alcohol than any of us is likely to pour down our drains is less than the amount that goes down the drains on a good Saturday night at your local boozer.

Straining IPA through a filter, will not remove the resin that’s mixed into the IPA already, only the cured particles.

Proof of that, is that you can strain the particles out of the IPA, then put the liquid in the sun, and it will turn into gelatin.

So if you pour that down the sink, you’re pouring contaminated IPA into the sewer.

I agree. That’s why I said to put the IPA in the sun for a while before straining it.

I doubt there’s any practical way to get 100% of the resin out of the IPA. But far worse than a bit of cured resin mixed with IPA goes down domestic drains every day (read the MSDS on the Resin, it’s surprisingly “benign”). The IPA component doesn’t matter anyway, you’re allowed to put that down the drain. And I figure treatment plants ought to be able to filter out any remaining resin just like they filter out fine organic particulates…

Some municipalities have “household chemical” disposal dropoffs. If you’re lucky enough to live somewhere that has such a service you could go there instead of pouring your IPA down the drain. The only other alternative is to pay for disposal, which can be a pain in the *ss since that’s federally regulated and there can be paperwork. Though if you’re using your FL printer in a commercial environment you might be required to do this by law anyway.

I am using mine in a commercial environment. Luckily we already have a company that comes weekly to pickup Acetone, mop water (oil contaminated), ozzy juice, and a few other things, so I just added the used IPA to the list. We get 5 gallon jugs and that lasts me a few months depending on my print load.

I did happen to ask my guy today what the law is. He of course said it differs county to county, but where we are (Los Angeles) it is illegal to dump IPA.

Thanks everyone! I called the local reclamation center and they said we can turn it in there. We’re up in the bay area so it’s probably about the same as in LA.

If you’re looking for tight regulations on the disposal of chemicals, you’re going to find them in California before you find them anyplace else in the US… But on the positive side, at least for consumers it seems California realizes people would pour the stuff down the drain anyway if it cost them anything to get rid of and they give you a place to get rid of it.

It’s a very good thing that California regulates environmentally hazardous substances. It takes a trivial amount of effort to meet those requirements relative to the benefit of doing business and living in this State.

For those who suggest pouring it down the drain, as a few posters have already pointed out: it’s not just IPA. It’s IPA permeated with both solid and liquid resin (gelatinous). Straining out the larger particulates with a paper towel doesn’t cut it. Used IPA should be treated as a hazard; our sewer and water-treatment systems are not designed to process it in any quantity.

The simple solution is to drop it off at your local county toxic waste disposal, which is open M-F and part day on Saturday. Drop off is free and you won’t have to worry whether some part of your IPA residue end up in the ocean or the local water supply.

You’ll notice that FL is conspicuously silent on this topic, which is all the more the shame because IPA is the largest consumable associated with their printer. My guess is that they are well aware of the environmental issues, but for marketing purposes don’t want this topic associated with their business.

If so, that would be a shame. It’s almost always better to be out in front on issues like this. It’s also irresponsible. Given the nature of used IPA and the quantity produced by their customers, FL has a corporate responsibility to communicate environmental risks and instructions for safe disposal.



I agree with most of your points here. To play devils advocate here for a moment, not everyone lives in the big city where a “local county toxic waste disposal, which is open M-F and part day on Saturday” is probably not true. Still not an excuse however, I agree its a toxic substance and sewer systems were not designed to handle it.

Regarding FL’s stance on the matter…or lack there of. While I do not think they suffer from any sort of an image problem at the moment I do think it certainly couldn’t hurt to add something like this to their site:

(that’s their about us page…obviously the 4th link does not exist now…I added as an example)

On such a page they could quickly and easily address the issue of IPA being toxic, contact your local waste management, etc, etc.

They could have links such as (sorry these are U.S.-centric links):


They could also add a best practices for the disposal of resin cartridges, trays, etc.

Just my $0.02


Thanks for your input Padua. All very good points and exactly why I originally posted that question here. It was very concerning to me seeing all these warnings on all the chemicals about the extreme hazards of coming into contact with ground or surface water systems and particularly any aquatic environments. I like my seafood! Just trying to do our part to be environmentally conscious and handle the materials responsibly. And I agree, It would be nice to have FormLabs give information on the proper disposal procedures or some kind of information on the subject. Thanks again for everyone’s input


You guys are awesome, seriously. I am going to take my soapbox and go home now.


Haha that brings me back to the days when I hosted and managed a fairly sizable forum many years ago which occasionally got political.


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Depending on my mood, I pour it on weeds, burn it in a pan, or just pour it on the rocks around the house.

So far it seems that broad leaf weeds don’t like the stuff. It does lightly stain concrete; but I suspect it weather off in time.

It’s just rubbing alcohol, please keep the EPA environazis out of the picture.

Go forth and print.

Yeah, but no, it’s not. It’s rubbing alcohol with resin mixed into it. The concern isn’t the IPA so much as that remnant amount of resin in the IPA.