coolant soluble oil vs. synthetic

[Santa Fe]

What do you prefer between soluble oil coolant and the synthetic coolant?

 

I have heard that soluble oil is better because it does not harm the paint on the machines(?) but I wonder what gives me a better finish and a longer tool life.

 

A brief explanation of "why" would be good as well.

[cunder]

Paint loos seems to happen from cutting chips. Not sure which coolant type is best. I can recommend a recyclers that filters well and removes tramp oil. http://www.smartskim.com/

[chris m]

Coolant has been discussed at length over the past few years; try a forum search for 'coolant' and you'll most likely get enough information to make your head explode.

[Dave.L]

quote:

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I have heard that soluble oil is better because it does not harm the paint on the machines(?) but I wonder what gives me a better finish and a longer tool life.

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2 Years ago we switched from ValCool Semi-Synthetic to Ho-Cut 795B Soluble Oil. We should have switched 12 years ago....

 

1) It does react with the paint inside our machines, but this is not an issue for us, it does not hurt the paint on the outside so the issue must be constant contact.

 

2) Way, way, better finishes.

 

3) Better tool life, but no good data to support how much.

 

4) Big issue, NO rust EVER!!. When the water evaporates, a nice fill of oil remains.

 

5) Ho-Cut 795B is bio-stable, no stink in the sump.

[5 AX]

There is no correct answer. It is all based on your application. I believe the major difference between the two is that synthetic is strictly a coolant until it reaches a certain amount of heat and pressure. Soluble oil is a coolant and a lubricant. The semi-synthetics try to overcome this by just adding soluble oil. This gives them some lubricity at low pressures. So, lets say you have very heavy cutting pressures and high heat I would lean toward a synthetic coolant. It will increase the life of you tooling. If you are taking light cuts in aluminum and or tapping small threads a soluble oil will be a better solution.

[Santa Fe]

Well, it is difficult to define a specific application since I cut mild steel, tool steels, aluminum, plastics and whatever knocks on my door.

 

I guess most important for me is to protect the machines from rust and to avoid any bad odors coming from the coolant. So, which of the two tends to smell bad sooner and protect less for rust?

 

I do keep a small air pump making bubbles in the coolant tank 24/7 and it seems to keep it well oxygenated.

[Dave.L]

quote:

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I guess most important for me is to protect the machines from rust and to avoid any bad odors coming from the coolant. So, which of the two tends to smell bad sooner and protect less for rust?

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Read my prior post. BTW, NOT all soluble oil is bio-stable, must are not so be careful. We never use bubblers and sometimes machines sit for weeks (another story) with no stink at all.