Where does silicone grease make sense?
Grease consists of a base fluid, a thickener and additives, so the use of a silicone grease depends on its complete formulation and the specific material pair, not on the silicone alone. Example data sheets for silicone greases list plastic-to-plastic, plastic-to-metal and metal-to-rubber contacts, seals, O-rings and parts exposed to water.
In industrial maintenance, silicone grease may be considered for:
- guides, bushes and other plastic-to-plastic or plastic-to-metal contacts when the product data covers the materials and motion range;
- O-rings, seals and elastomer parts after compatibility with the specific material has been checked;
- valves, pumps and vacuum systems when this use is stated in the documentation for the particular product;
- electrical components when the product is documented for high-voltage protection or insulation.
Where do the limitations come from?
Temperature depends on the formulation and the application
The operating temperature range belongs to a specific formulation, not to silicone greases as a group. In the Molyguard catalogue, CSO SYL has an operating range of −25 to +160 °C and HVG of −5 to +220 °C. Dropping point does not set the upper operating limit: it is 180 °C for CSO SYL, and the MOLYKOTE PG-21 data sheet gives 250 °C with a service temperature of up to 190 °C. Check the data for the specific product, heat dissipation, running time and short temperature peaks.
Load and speed can rule out a product that looks suitable
Some silicone-grease data sheets limit use to light or medium loads and slow or medium-speed movement. Do not extend that statement to the entire category, but do not assume that every silicone grease suits a heavily loaded steel bearing or a fast mechanism either. For metal-to-metal contact, you need load, speed, wear and test-method data from the product and equipment documentation.
Material compatibility must be checked
A grease described as compatible with plastics or elastomers still has to be assessed against the specific material, temperature and contact time. An unsuitable lubricant can cause swelling, shrinkage, cracking or a change in hardness. For a new material combination, plan a compatibility test and do not mix products without the manufacturer’s confirmation.
How should you read the product data sheet?
Before replacing the current grease with a silicone product, check:
- base fluid, thickener and additives;
- operating temperature range and the conditions for which the manufacturer stated it;
- load, speed, type of motion and any limits for metal-to-metal contact;
- the materials of the parts, seals and O-rings and how compatibility was established;
- application, cleaning, dispensing and changeover instructions.
If the data sheet does not answer a question that affects the decision, do not fill the gap with a category name or product colour. Request the documentation or run a controlled test.
Examples from the TC Kolor range
The silicone grease range at TC Kolor contains four Molyguard products, and the catalogue assigns each of them a different function. CSO SYL is a grease for bearings and mechanical parts in plastic casings, based on lithium and a mineral-silicone oil. HVG is a silicone compound for high vacuum, valves and pumps. HVG EN is intended for protection against high electrical voltage, and SYL 133 for protecting O-rings and seals and reducing plastic-to-plastic noise.
Selection therefore starts with the function of the lubrication point. Suitability for a particular plastic, bearing or seal still has to be confirmed in the product data sheet and the machine documentation.
When should you choose a different lubricant?
Consider another product group when the main issue is high metal-to-metal load, high bearing speed, contact with a particular chemical or unconfirmed compatibility with the material. Check a food-grade requirement for the specific product as well, not for the whole group.
How to prepare the selection at a plant
- Identify the point. Record the part, machine, manufacturer, part number and mounting arrangement.
- Describe the materials. State the plastic, elastomer, metal, seal type and any process contact.
- Collect operating conditions. Measure or confirm temperature, speed, load, moisture, dust, chemicals and running time.
- Check the current product. Record its name, base, thickener, dispensing method and cleaning procedure.
- Compare the documentation. Confirm the use case, compatibility, operating range and limitations of the specific product.
- Plan the test and observation. Define the acceptance criterion, observation period and inspection method after the change.
Send the data from steps 1–4 in an enquiry from the silicone grease range page. With this data, a specific formulation and its limits can be checked before a production trial.
