Best Way to Filter Bike Chain Solvent?
 

Paper coffee filters remove sand/grit from mineral spirits/kerosene but don't completely remove black grime even using 2 bottles of solvent to clean. One could use 3rd or 4th bottle of solvent but unless one introduces new ($$ & non-green) solvent all the bottles will get blackish. I used to use spray degreaser & water hose to clean chains (& before that scrubbing chain in kerosene). But now spray degreasers are much weaker & IMHO somewhat useless.

Anyway, are there better methods to filter solvent than coffee filters? Perhaps a car/truck oil filter?

Filtering is a PIA and 100% totally unnecessary. Put the solvent in jar with a tight lid and set it aside for a week or two. Everything except dissolved oil will settle to the bottom and clean solvent can be decanted like a fine wine.

Like the wine, stop decanting before the settled dirt begins to pour out. Managing this way, you'll never get to use the lase bit of solvent, but can continue to use the same jar to settle and recycle solvent forever.

If you don't have the time for gravity to separate the dirt, you can speed up the process with a centrifuge. I'm sure Harbor Freight has some nice ones at a decent price.

Or be lazy like me and don't degrease your chains. I just relube & wipe off excess.

I just fire up the pressure washer or head to the self serve car wash. Give it a good dose of citrus degreaser, let soak awhile and blast it off.

I think I have been using the same qt of gasoline for 5 years.

If necessary, coffee filters do a good job filtering particulates.

Interesting, thanks. I use large restaurant-size coffee filters so filtering is not esp time-consuming but if it doesn't clean out the black grime I suppose why bother & just decant as you suggest.

BTW, while sand & grit is obviously not good for chains (wear & friction) I wonder about the black grime's effect on wear/friction? I guess it's fairly minimal but OTOH never read any research about that. At any rate it's a hazard to clothes & car interiors.

A couple of experts on the touring forum used that on long-distance tours & said it worked fine. I guess it depends on how thoroughly it's done. Currently I'm using Rock 'n Lube which recommends applying generously to flush out dirt & then wipe. OK but that stuff is pretty expensive.

BTW in the old days cars used to burn a bit of oil so it was easy to find empty oil cans in gas station trash cans. Oil cans had enough oil left to lube & wipe chain, for free.

Self-serve car wash sounds like good idea for tourists w/gunked-up chains. Don't have a pressure washer but buying a good pin-point hose nozzle would help. Pro team mechanics use degrease 'n hose spray. While the old engine degreasers worked better I just now read that there are big differences in current citrus degreaser quality so I'll have to give them a try again.

You are misunderstanding what is happening when you use a solvent. When you use it on your chain, you'll get a mixture of solvent, oil and particulates. In chemistry we call this a heterogeneous mixture. You can separate the particulates from the solvent/lubricant mixture with the coffee filter. Now you'll have a homogenous mixture. A homogeneous mixture can't be separated by simple filtration. You could distill it but that's not easy to do at home nor would I suggest it, even if you had the training. And, if you had the training to do a distillation, you'd know enough not to do it at home.

The good news is that a mineral spirits will carry a lot of chain lubricant and still be very effective.

D-limonene is "citrus solvent" in its pure form for oils it is stronger than odorless mineral spirits, about equal to turpentine, and weaker than tolulene. The strongest around is an equal mix of toluene and MEK, if you have some old dry grease cake that the others won't soften a day soak in this will. Mild heat helps.
Above that you go to nitroamines for varnish like deposits.
Some cruds respond better to semi-polar solvents like acetone alcohol and MEK, like dumond tech.

Coffee filters are good for about 20 microns and auto oil filters are also good for 20-30 microns.(ish, tests and rating types and efficiency vary) large truck bypass oil filters are about one micron.(they are secondary to the main oil filter and only handle about 5% of the oil flow)

How much solute dissolves in a solvent is dependent on the identity of both and the interactions between the solute and solvent. Some solvents can dissolve infinite amounts of solutes like sugar in water, ethanol in water, acetone in water or even oil in mineral spirits. Other solutes only have limited solubility in certain solvents. Even the measures of solvent "strength" depend on the solute and the solvent as well as what you are measuring.

And that doesn't even take into account the cost, toxicity or flammability of the solvent. d-Limonene may be a great solvent but it costs around $40 a gallon. A gallon of mineral spirits cost $15 per gallon.

MEK and xylene cost around $20 each but are more flammable and more toxic. The reason I list xylene rather then toluene is that toluene is more difficult to find because of its toxicity. For the casual home user, mineral spirits is a better choice for cleaning chains and and bearing surfaces. It's cheap, relatively safe and efficient.

In my experience, mineral spirits will take care of even varnish deposits in 5 to 10 minutes.

Honestly, 20 microns or 0.02mm is good enough for a bicycle chain. One micron...0.001mm...is overkill for the application. And it won't remove the dissolved oils at all.

It is possible to over think this and trying to find a "better" solvent or a filter to take out smaller particles is certainly overthinking the problem.

Yeah, I don't like the idea of introducing solvent inside my chains; too easy to wash crud in, and too hard to get it out.

Much better IMO to prevent it getting dirty in the first place - I never let my chains get past the point where a quick wipe with a rag slightly damp with solvent is all they need before lubing. If there's dirt, I'll brush it off.

Importantly, when lubing I'll use a single drop per roller rather than dragging the chain under a stream of oil, and spend a bit of time wiping off as much excess as I can.

For mine, if you have to take the chain off to clean it, you've already lost... twist that sucker and feel all the grit inside it, before and after your cleaning efforts.

Yep, I'm aware of miscibility and we are speaking of non-polar solutes.(except dumondtech)

toluene and xylene are very similar in most respects, plain benzene is by far the toxic one of the family. I didn't list it as the first choice(mostly due to price).
d-limonene is actually fairly toxic but it makes people think "natural and fruity". It also has emulsifying properties that petrol distillates don't, and it works well in low concentrations, the cost is a small factor if it is reused many times.

I haven't actually seen a bicycle part develop varnish, I have meet varnishes in other mechanics that laughed at a week long soak in kerosene, but took only a few hours in a warm bucket of nitroamine solution("carb dip" more of a chemical reactant than a solvent, water rinse-able end product); and the grease cake(no oil left in it and is found in vintage bicycles) that resisted gasoline and kerosene for days with daily shaking, but in one day with toluene/MEK soaking it slipped right off (destroyed my nitrile gloves in a couple of minutes too)

With the right containers[w/lids too] it only takes a few ounces of the strong solvents, once dissolved the final rinse is with the cheap and easy stuff. I've been working with the same few quart cans for a decade, not because of filtering but just good thrifty use and getting a few uses out of each batch.

As for filters I was presenting options, not suggestions. Which reminds me; if oil becomes excessively concentrated in the solvent they can be separated with simple distillation as is used with commercial parts washers, this would also leave behind any hard abrasive contamination.
While it isn't worth the effort for a bike chain due to rapid re-contamination with road dust, a sub micron filtration of the lubricant would [if kept clean] significantly extend the wear life of the parts as they don't operate within the hydrodynamic or elastohydrodynamic lubrication regimes, due to the slow speeds and start-stop oscillation type movement, the chain is in a boundary-heavy mixed state most of the time, meaning that there is less than a micron of lube and lots of direct metal contact between the microscopic high points of the surfaces while under load.

I usually end up tossing my well used solvents on the fire.

I find turpentine (or similar stoddard solvent) to be a better solvent where "varnish" residue from gasoline has built up, though not needed for things like bike components. Back in the day, I used stoddard solvent in parts cleaners working on powered aircraft and motor vehicles.

Like many others, I just let particulates settle to the bottom of the jar and pour off the supernatant.

Benzene is particularly bad because of it's mutagenicity.

I suspect that at reasonable levels, the dissolved lubricant may actually be beneficial helping carry away the particulate and leaving a lubricating residue behind in places that thicker lubricants don't reach. Real mineral spirits are still my choice for cleaning chains and drivetrains off the bike. I worry about foaming degreasers, etc. leaching into bearings when used around wheels and BBs.

The "black grime" IS the particulates, the sand and grit. The solvent and dissolved grease are not highly colored. The dark color in the grit comes from the finely divided metal particles, not the liquids. Once you filter those out, your still contaminated solvent (grease) should be light colored. And without the particulates, there will be no reason for the solvent/grease to cause wear.

put the things being cleaned in a wire basket, and let the grit settle to the bottom of the outer container under the basket.

then see FB's decanting suggestions.. with Kero , or other solvents that evaporate ,

that last bit will evaporate leaving just the sludge.

I'm a fan of centrifuges but there is a definate investment economy of scale there. Centrifuge plus the pump and enough solvent stock to make it worth while. 60 GPH Centrifuge for WVO Motor Oil and Biodiesel | eBay
Faster and less energy usage than distillation but distillation separates the oil. Use both of them and you could actually reuse a tiny bit of your chain oil, :p

Oh! almost forgot, Biodiesel is a hell of a strong solvent. (Eats up most gaskets and all sorts of other stuff, fuel systems need special teflon seals to handle it.)

No, the 'black grime' isn't the sand and grit. Those are mostly colorless. You are correct that the black color mostly comes from the metal that the sand grinding up the chain because the sand is harder than the steel. You could leach the steel away from the silicon dioxide after you've filtered and/or distilled the solvent off. The best way to remove the steel would be with hydrochloric acid...which isn't a solvent because it reacts with the iron.

Yes. Put a magnet against the solvent bottle and it will attract the black goop. It is mostly wear products (metal) from the chain.

Wouldn't this make placing a magnet in the bottom of a tall narrow container yet another way to make sure that the metallic portion of the particulate isn't being redistributed during the decanting? Cheap, easy, reasonably clean, reusable etc.

Interesting, thanks. The truck bypass filters seem to be a bit $$. Wondering about DIY solutions like filtering thru activated charcoal or whatnot? But that would probably be more of PITA than needed.

Have used the wire basket/kerosene approach with decent if not spectacular results. Perhaps best method is to do degreaser/water spray & then do final cleaning w/kerosene or mineral spirits. I'm not actually a clean chain fanatic but just wondering about various techniques. Like with car paint/window cleaning, some techniques may seem unnecessarily troublesome but pay off by making future cleaning easier.

BTW a good way to spot a bad driver is to check out front wheels. Bad drivers over-use the brakes & get excessive black disc residue on front wheels.