Question 1

What is the ideal dilution ratio for water-soluble PAG metalworking fluids?

Accepted Answer

Water-soluble PAG concentrations typically range from 5% to 15% in water. Heavy-duty cutting and grinding operations require higher concentrations for lubricity, while light grinding utilises lower concentrations for maximum cooling.

Question 2

How do you check the concentration of a diluted PAG fluid in the workshop?

Accepted Answer

Concentration is most easily measured using a portable handheld refractometer. Read the refractive index on the Brix scale and multiply by the fluid's specific refractometer factor to determine the concentration.

Question 3

Why is water quality important when diluting water-soluble PAGs?

Accepted Answer

Water hardness, chloride levels, and bacterial content influence fluid stability. Hard water can cause emulsion instability and mineral scaling, while high bacteria levels lead to fluid spoilage, making deionized water the preferred choice.

Question 4

Can I add water directly to the PAG concentrate to dilute it?

Accepted Answer

Standard practice dictates adding the PAG concentrate to the water while continuously agitating. This ensures a homogeneous solution and prevents localized high-viscosity gels from forming.

PAG Lubricant Dilution and Concentration Calculator

Dilution Result

Dilution Curve