Our outflow will run with many colors.

March 25, 2008 8:52 PM

My wife paints with oils. We're buying a house with a septic system. Will cleaning brushes in the sink be a problem?

Basically, what are our options? I've never lived in a house with a septic system. Additionally, it's a "wet property," with a pond on the lot (though out of the leaching field).

On a regular day in the course of our apartment living, she just cleans her brushes in the sink. Can she still do this? Or will the paints clog up the system? What do we need to worry about or look out for?

posted by nevercalm to home & garden (8 comments total)

What does she use to thin them with? Stuff like turpentine, linseed oil, and some of the pigments in oils are pretty nasty. I don't know anything about water soluable oils.
You should be googling "proper disposal [thinner],"
posted by blackunicorn at 10:45 PM on March 25

She shouldn't be washing out her oil paints in the sink in the first place. She needs to get a dedicated container for old turpentine, paints, etc, with a funnel into which she empites them. This should be kept as safe and closed since it and its fumes are flammable. When it's full, she should take it to be properly disposed of by a toxic materials-handling service (possibly provided by the city in which you live).
posted by beerbajay at 2:27 AM on March 26

Yeah regardless of where it's going - NO CHEMICALS in the sink!! I use acrylics but they occasionally go for a dip in something eye watering and none of that goes down the sink. (It's still under the sink...)
posted by mu~ha~ha~ha~har at 2:51 AM on March 26

Citrus-oil-based solvent cleaners do a good job of cleaning up oil-based paints, and are readily biodegradable. Lead, cadmium and other nasties in the pigments will settle into the bottom of the septic tank, and leave with the sludge when you get your tank pumped out (which you will need to have done every five years or so). Linseed oil (the main oil used in oil-based paints) is readily biodegradable in a septic tank if reasonably well emulsified (as it will be if you clean up with a citrus cleaner).
posted by flabdablet at 4:07 AM on March 26 [1 favorite]

If using turp or other thinners, these can be re-used almost indefinitely. Pour some turp into a bowl, clean brushes. Pour used turp into a jar and seal. Finish washing brush with a little soap and water. This puts only a miniscule amount of turp down the drain. In a few days, the paint solids will be at the bottom of the jar, clear turp on top. You can now clean brushes with the clear stuff, pretty much until the whole jar is full of settled solids. Finally discard the jar of solids.
posted by beagle at 5:19 AM on March 26

Yeah, that works to a certain extent, but eventually the thinners get too loaded up with paint oils and binders and you may as well try cleaning your brushes in lacquer.

I like a three-jar system: keep a filthy jar, a dirty jar and a clean jar. Do the first wash with solvent from the filthy jar, then squeeze out the excess and re-wash with solvent from the dirty jar, then squeeze out the excess and re-wash with solvent from the clean jar. Cap the jars and let them settle between uses as beagle suggests. When the filthy jar gets too thick and nasty to be useful, leave it in the sun to dry out and then landfill it; the dirty jar becomes the new filthy jar, the clean jar becomes the new dirty jar, and I get a new clean jar with fresh solvent.

I prefer citrus-oil-based solvent to turps, because it makes the garden shed smell nice as the filthy jar is drying out.
posted by flabdablet at 5:38 AM on March 26 [2 favorites]

Real turpentine (as opposed to mineral spirits) is distilled pine tree sap. Some google searching claims that it is biodegradable.
posted by gjc at 7:28 AM on March 26

If you have a septic system, I'd strongly advise against dumping mineral spirits, turpentine, linseed oil etc into it. It won't be able to do its job of breaking down its contents, will soon fill up faster than ever and you'll be paying to pump it out that much more often. You'll contaminate it so it may never recover, even after pumping out... it's just not that organic as some real organic waste.

What flabdablet suggested, 3 can monty.
posted by alicesshoe at 8:15 AM on March 26