Hydraulic oil settling out

[MapleLeafFarmer]

So we all know paint settles out over time with its additives and clays settling to the bottom. So we stir or shake.

How about our 5 gallon pails of hydraulic fluid. Does its additives settle?

Anyone shake before pouring from their bigger containers?

 

[5030]

Not that I'm aware of.

 

[JJT]

Never

 

[FordnMassey]

Perhaps we should if it's been around for a while. I had a drum of STOU aka UTO aka Universal oil that was 5-15 years old. It came with the property. When I removed the top of the drum to use it as a container, there was a soap like semi solid stuck to the bottom. I'm sure that should be mixed with the oil.

 

[5030]

I never use cheap fluid and I'd never trust something someone left behind in the first place.

 

[MapleLeafFarmer]

I took a 1 day lubrication / oil seminar and they told us YES new oil in sealed containers may separate. Open containers risk increases, older oil increases, and storage poorly increases settling. The more expensive oils (more additives) also increases risk.

I tend to buy OEM oils (think expensive) and was told the more expensive the oil the higher likelihood it has higher levels of additives and subject to more settling. Higher priced (Better??) quality oils sometimes have between 10 and 30% additives and these additives can and may separate over time in sealed containers.

We talked about a huge list of additives that may be present in the oils like anti-oxidants, rust inhibitors, viscosity index improvers, anti-wear agents, ZDDP, TCP, detergents, dispersants, anti-foaming agents, friction modifiers, demulsifiers, emulsifiers, biocides, viscosity improvers, pour point depressors, etc / etc / etc..... We were told the more expensive oils have more additives and may have more settling over time.

The diesel engine oil i am buying spec'ed out to 25% additives in it and the hydraulic oil 10% so I was told in the testing part of the class to consider separation especially on drums and 5 gallon pails that have been opened (partially used). I store indoors out of heat and sun light and rain, etc... in a very moderate temp. region so risk is low but still to take care I was told. If i would switch to the cheapest oils (very few additives) then settling would be even less of a concern but then other concerns pop up.

 

[FordnMassey]

I never use cheap fluid and I'd never trust something someone left behind in the first place.

Hi,
Just passing on an observation that some oils do separate, presumably after a long time. MapleLeafFarmer makes some interesting points.

 

[rScotty]

Hi,
Just passing on an observation that some oils do separate, presumably after a long time. MapleLeafFarmer makes some interesting points.

Just letting the solution sit It is a common technique use for separating and concentrating portions of chemical solutions. Especially useful with particles too small to be filtered. It is a common technique. There is no reason why it wouldn't work just as well for additives in oils.

The solution has to remain absolutely still, and can take months - but it works well. It's a well accepted lab technique when you need something with greater purity than a centrifuge will yield. Almost everything liquid will either precipitate or stratify. The concentrated or stratified layers are then siphoned off.