Thread: Recycling oil

I asked a similar question over at homeshop machinist and was howled down by most, but I can't see why not. Oil in a car is subject to combustion processes but in machine tools there is not the thermal breakdown so the only things wrong with the oil would be particles (as you suggest, automotive oil filter and perhaps a magnet) and water/ coolant pick up.
I do something similar with solvent after degreasing dirty parts - I let the used solvent trickle through a coffee filter. The dirt stays in the filter while the solvent travels through.

Michael

Hi Bryan,

Just a thought, if you are going to the trouble of pumping the oil through a filter, why not go the extra step and put in an automatic lubrication system, you'll need the pump anyway...

I like the look of this unit... (I'm hesitant to link to live auctions, but it's a good cause..)
SHOWA Lubrication System Pump MLA03W 200V 3 PH | eBay

Regards
Ray

Careful Ray - you're in danger of voiding Bryan's amateur status with a proper piece of gear like that.
I was debating with myself whether the pump should be a vacuum type to pull the oil through the filter (like an old milking machine, although where he will find one of those locally...), or positive pressure. Positive pressure could even be something like an old spray pot with a bottom pick up and a few psi of air to push.
For a few litres a 3 phase lubrication system pump does seem a little over the top. Perhaps an engine gear pump might be the go coupled up to an electric motor.

Michael

A few years ago (may 10 or 20)I got a used power steering pump and hooked that up to a series of 2 oil filters (1st one a "toilet paper roll filter" - hailed as the best oil filter at markets at the time) and the second a regular car cartidge filter. It only took a 1/4HP motor to drive it with a decent reduction and the oil was definitely clean but still dark.
I learnt at the time that the oil 'particles' had been sheared in the peocess of being used in a car engine and could not be reused safely in a car (the original intention).
I've been using the filtered oil as bar oil in my chainsaw for a while without any ill effects. But I ran out a couple of years ago and haven't bothered setting it all up again and bought a containier of chain and bar oil.... I don't use the chainsaw that much these days to mess around....

However, for expensive machine oil which is not exposed the high speed and heat, filtering would probably be a good way of recycling the oil.

Try it.

Joe

Coffee filter, hmm. I wonder if ISO 68 will seep through under gravity? Worth a try. Could be set up in a corner with a drip feed and forgotten about. Would be great to not hassle with a pump.

I guess the main contaminant would be fine metal particles, most ferrous, but not all. So magnets have potential to assist. That and airborne grit, bugs etc.

Ray that rig looks the biz. Would be a 'non-trivial' project to set up though. Who knows what kinds of pressure and flow it produces, and what is needed?

Joe, I'm a believer in 'whatever' oil for chains (but clean). My reasoning is I don't want it to cling, I want it to fling off and take contaminants with it. Don't use mine much any more either, thankfully.

Thanks for the input guys.

Apparently we have no coffee filters. Our caffeine technology has Moved On. What do I know, I'm a tea man?
Before I buy some I'd like to ask you coffee heads: With the filtered stuff, do you still get 'fines' in your cup?

Hi Bryan,
I was thinking the same about gravity and time, Though if you were in a hurry Bunning have one of those pump up garden sprayers for about $10. Of course if the roof in your shed is pretty high you could likely get the same pressure hanging the dirty oil in a drum from the roof.

I'd think the oil people would say you will have lost some of the anti corrosive properties, but I'd say the shaper predates those anyway.

I'm not sure I'd bother for $24 of oil............. but I wouldnt let it stop me either . you'd have $24 more to buy something shiny

Stuart

A guy I know used to operate diesel generator power houses in remote areas 20 years ago. They used to have a dual oil tank system for the engine oil: while one lot of engine oil was in service the other one was being cleaned and treated. They had an Alfa Laval oil centrifuge which cleaned the carbon from the oil and then they had to neutralise the acids or something in the oil, this bit I'm not clear on but he said they had a device they called "The Vitamiser" which he said was a bit like a paint shaker. The oil and a measured amount of white sugar (heaven help any staff member who pinched any for their tea or coffee) was shaken together and then separated off to give fresh clean oil for the engines. I'll ask if any water was involved as well in the process as I can't remember if it was.

The explanation was that oil treated in this way is actually better than new oil as any crap non oil molecules get broken down over time and removed by repeated treatments leaving only mineral oil. Some of the oil was estimated to be over 30 years old and still in regular use apart from losses. Keep in mind these were big engines (Dormer I think) and well maintained so they wouldn't cut corners on lubrication. I'd imagine the oil was straight oil as there was no need for detergent additives if they frequently cleaned the oil. The Alfa Lavals were also used on big diesel engine ships to clean their oil too.

Another very slow method is to slip a length of oil soaked manilla rope into a plastic hose so it's a tight fit (don't ask me how you do that! maybe a wire to draw it through or compressed air to expand it) and then use it like a siphon from one high container to a low container. Over a period of months it's supposed to give clear oil. I haven't tried this myself though, it's supposed to be a boat engineer's trick.

I ran my Hilux for 18 months on used cooking oil and was told by any number of people that it would wreck my fuel pump, well after around 35000k's I can assure you it didn't. My process involved settling, heating and progressive filtering and I went through around 70lt a week.
If the number of miles I travel hadn't changed and if the oil hadn't become so bloody hard to get I'd still be doing it now.
I was looking at using one of these with a power steering pump before my supply dried up and I reckon it looked like a nice little toy:

Dieselcraft.com Waste Vegetable and Motor Oil Cleaning Waste Vegetable Oil | Waste Motor Oil | Biodiesel | WVO Centrifuges

I remember being told by an old timer that he used to put used oil in a bucket on the workbench and hang a hemp rope soaked in clean oil from that to a bucket on the floor. After a day or so the bucket on the floor would be full of clean oil having been filtered through the rope. Can't say as I ever tried it but it sounds like a neat trick.
Cheers,
Greg.

The slow speed diesels (600rpm) we had in the power station used a straight weight lube oil ( 60 w) IIRC ,with no additives ,we never changed the oil , used a centrifuge to separate the crap and pump it straight back into the engine .
Once a year we would pump out the floor pits under the engine beds and recycle the oil through the centrifuge put it in drums and use it to top up the engines when needed.
They were more economical on lube oil than the now used turbines 7000 litres of oil replaced every two years . I think I'm going to have to make a drip tray for under my shaper as it is open to the floor and any stray oil will go straight through .
Some thing to look at down the track.
Kev.

Tried gravity feed through filter paper rounds to remove carbon and solids from cleaning fluids. To say it's a slow process would be a large understatement, viscosity of way oil would make watching grass grow appear fast I'd imagine!

Probably be looking for alternatives to Fuchs too. Been a while between purchases, seems a little more spendy than I remember for other brands.

Some interesting and encouraging stories there. That centrifuge looks cool, but I won't be springing for it. My centrifuge experience is with Moto Guzzis. The early V twins just had a flywire screen on the oil pickup and an oversized gallery in the big end journal. This had a screw in plug for cleaning every... I forget, but whenever you had it apart basically. It was pretty effective at trapping fine sediments and if you didn't clean it you risked blocking the gallery and starving the bearings. Couple of things about that. First, it only spun at 2 or 3 K RPM most of the time, and second, the oil wasn't in there for long. So it seems like a simple centrifugal filter should be pretty easy to rig up (famous last words).

Bill, thanks for saving me the cost of a packet of filter papers. I used Fuchs because that's what was available locally. I will shop around more next time.

Originally Posted by Stustoys

I'm not sure I'd bother for $24 of oil............. but I wouldnt let it stop me either . you'd have $24 more to buy something shiny

Think of it this way: If I re-use that $24 four times, it's worth $96. If I re-use it indefinitely, I'll be rich! <maniacal laughter>

You could make a waste oil heater and burn the oil.

We have oil recyclers here, so all my oil and waste solvent goes to them for re-refining, as does my employer and they buy oil and coolant in staggering amounts. If it was economical to filter and clean it in house they would.

Pete

Your employer needs refining????