Vasundhara Specialities — Authorised Castrol Industrial Partner — supplies the complete Castrol Molub-Alloy assembly-paste range across South India — formerly sold as Castrol Optimol. Molub-Alloy Paste MF (screw connections and threads to 1,100°C), Paste White T (white assembly paste to 250°C, prevents fretting corrosion) and Paste PL (press fits and pressurised sliding points under high pressure). For thread anti-seize, friction-control and assembly applications. Pan-South-India dispatch from Hyderabad warehouse.
Castrol Molub-Alloy assembly pastes, formerly sold as Castrol Optimol — Molub-Alloy Paste MF for screw connections, spark-plug and Lambda-probe threads to 1,100°C, Paste White T for assembly work to 250°C where fretting corrosion is the failure mode, and Paste PL for press fits and pressurised sliding points. Critical for stud and bolt threads exposed to corrosion or heat. Vasundhara Specialities supplies the full Molub-Alloy paste range across AP and Telangana from Hyderabad dispatch.
Castrol Molub-Alloy is the industrial paste range used wherever thread protection, friction control or assembly lubrication matters more than catalogue defaults. It was sold as Castrol Optimol for years, and plenty of drawings and store bin cards still say so. The economics are sharp: a failed bolted-thread joint on power-plant or refinery equipment costs lakhs to recover — drilling out the broken bolt, retapping the hole, possibly machining a thread insert — against a few grams of paste at assembly. Molub-Alloy Paste MF (synthetic carrier with temperature-stable solid lubricants, working range -40 to +1,100°C) is the one to know: Castrol specifies it for high-temperature screw connections, spark-plug threads and Lambda-probe threads, and nothing else in the range goes near that temperature. Molub-Alloy Paste White T (mineral and ester base, -30 to +250°C) is the white assembly paste — it prevents fretting corrosion and is specified for short slide paths and for long-term lubrication of slide and guide elements such as screws, hinges and chucks, with no metal particles to stain the part. Molub-Alloy Paste PL (mineral base with bentonite, -40 to +450°C) is the high-pressure grade for pressurised sliding points, tight and press fits, slide bearings and gears. For power-generation maintenance across the captive-power steam-turbine base in the cement belt, Paste MF is the grade for boiler and turbine-component thread protection. For stainless assemblies in Hyderabad pharma plants, tell us the joint and the temperature and we will confirm the right grade against the product data sheet rather than guess it. Vasundhara Specialities supplies the full Molub-Alloy paste range across AP and Telangana with technical-application support for specific bolted-joint specifications. Castrol India's industrial product line covers the complete temperature-and-application range.
The three pastes in Castrol's India Molub-Alloy range, formerly sold as Castrol Optimol.
Grease-like carrier with temperature-stable solid lubricants on a synthetic base, working range −40 to +1,100 °C. Castrol specifies it for components exposed to corrosion and extreme temperature — high-temperature screw connections, spark-plug threads and Lambda-probe threads. Nothing else in the Castrol paste range goes near this temperature.
White paste on a mineral-and-ester base with inorganic and lithium thickener, NLGI 1, working range −30 to +250 °C. For assembly work, base and thin-film lubrication. Prevents fretting corrosion, and Castrol specifies it for short slide paths and long-term lubrication of slide and guide elements — screws, hinges and chucks. No metal particles, so it does not stain the part.
Mineral-base paste with bentonite and solid-lubricant thickener, NLGI 2, working range −40 to +450 °C. For pressurised sliding points and for basic and thin-film lubrication under high pressure and temperature — screw connections, tight and press fits, slide bearings and gears. The grade for assembly work where load rather than heat is the problem.
Standard property values across the range. TDS / MSDS / per-batch COA available on enquiry.
| Property | Molub-Alloy Paste PL | Molub-Alloy Paste White T | Molub-Alloy Paste MF |
|---|---|---|---|
| Base oil | Mineral | Mineral and ester | Synthetic |
| Thickener / solid lubricant | Bentonite, solid lubricants | Inorganic and lithium | Temperature-stable solid lubricants |
| NLGI consistency | 2 | 1 | Paste, grease-like carrier |
| Working temperature (°C) | −40 to +450* | −30 to +250 | −40 to +1,100 |
| Typical service | Press fits, tight fits, screw connections, slide bearings, gears | Assembly work, screws, hinges, chucks; prevents fretting corrosion | High-temperature screw connections, spark-plug and Lambda-probe threads |
* The upper figure for Paste PL refers to the effect of the solid lubricants, which is how Castrol's catalogue states it. Figures above are from Castrol's India industrial product catalogue; only the properties stated on the individual product data sheet are binding, and we send the current data sheet with any quotation. Pack sizes are confirmed at enquiry. These pastes are not NSF H1 food-grade — for food and pharma direct-contact thread applications see the Castrol Optileb range.
If you have Optimol on an old drawing, a store bin card or a purchase requisition, you are in the right place. Castrol's paste range is now branded Molub-Alloy, and this page carries the current names. We still take enquiries against the old ones — send us the Optimol code you have and we will come back with the Molub-Alloy equivalent.
Molub-Alloy covers both pastes, which is this page, and high-performance greases — Molub-Alloy 936, 777 and 8000 for mining, open-gear and severe-duty service, which are on our Tribol and Molub-Alloy greases page.
Where Castrol Molub-Alloy Assembly Pastes ship from our Hyderabad warehouse — by industry segment and application profile.
Molub-Alloy Paste MF for steam-turbine and boiler-component bolted-assembly threads, where the working range to 1,100°C covers the hot-side joints. Paste White T for flange and piping threads at lower temperature. Power-plant maintenance and turnaround service.
Molub-Alloy Paste MF for foundry-furnace and steel-mill stand bolted-assembly threads. Heat-soak protection for studs and bolts in continuous high-temperature service, which is exactly the duty Castrol names it for.
Molub-Alloy Paste White T for stainless piping and flange bolted-assembly threads in pharma and food-plant service — it prevents fretting corrosion and leaves no metal particles on the part. Note these pastes are not NSF H1; for direct food contact see the Optileb range.
Molub-Alloy Paste PL across heavy-equipment and mining maintenance — press fits, tight fits and bolted-assembly threads carrying high load with dust and shock exposure. Removes the risk of seized threads at planned maintenance and breakdown service.
Molub-Alloy Paste MF is specified by Castrol for spark-plug threads and Lambda-probe threads — the two joints that seize most often in engine service and cost a cylinder head when they do. Working range to 1,100°C.
Molub-Alloy Paste White T for general bolted assembly and Paste PL where the joint is a press fit or carries high pressure — petrochemical, chemical-process and oil-and-gas piping thread protection.
Visit Us: Bhimavaram, Andhra Pradesh | Authorised Castrol Industrial Partner supplying Hyderabad and South India | Pan-India dispatch via authorised distribution network.
Common questions from maintenance and procurement buyers sourcing Castrol Molub-Alloy assembly pastes through Vasundhara Specialities.
Temperature decides it. Castrol gives Paste White T a working range of -30 to +250°C, so it covers most plant-maintenance bolted assembly, and it has the advantage of leaving no metal particles on the part. Paste MF runs to +1,100°C and is the grade for exhaust components, furnace assemblies, kiln-component threads and anything else sitting above what White T is rated for. Default to White T and specify MF once sustained temperature goes past its range. Where the joint is a press fit or a pressurised sliding point rather than a hot one, Paste PL is the answer instead.
Stainless threads have a specific failure mode: galling, where the threads cold-weld to each other under tightening load and seize, destroying both the bolt and the receiving thread. The fix is to keep a lubricant film between the two stainless faces so they never make direct contact under load. Castrol's India Molub-Alloy paste range is Paste PL, Paste White T and Paste MF, and the right one depends on the joint temperature and the load rather than on the fastener material alone. Send us the joint temperature, the fastener size and whether the assembly is disassembled routinely, and we will confirm the grade against the product data sheet.
It lasts as long as the joint stays undisturbed and the paste stays in place, which is why the honest answer is a range set by your conditions rather than a single figure. Heat cycling, corrosive atmosphere and washdown all shorten it; a dry, stable, moderate-temperature joint holds protection for a long time. The rule that matters is simpler than any number: re-apply fresh paste every time the joint is disassembled. A previously pasted thread that goes back together dry loses its protection, and that is the most common way a joint that was protected once seizes later.
The concern with aluminium is galvanic: a paste carrying metallic particles of a more noble metal can drive corrosion of the aluminium in wet service. Molub-Alloy Paste White T is the white paste in the range, thickened with inorganic and lithium rather than metal particles, which is why it is the natural starting point for aluminium threads. Confirm it against the product data sheet for your specific joint before you commit, especially where the assembly is wet or washed down.
Paste pack formats vary by grade and by what Castrol is currently filling, so we confirm the exact size and lead position at enquiry rather than publish a list that goes stale. Tell us the grade and the annual volume and we will come back with the pack options and current stock position in writing.
No. Molub-Alloy Paste PL, White T and MF are general industrial pastes, not NSF H1 registered. For food-plant and pharma-plant thread applications that require NSF H1 compliance, refer to the Castrol Optileb food-grade range — see our Optileb page for the NSF H1 paste alternatives. For non-food-contact applications inside food and pharma plants, the standard Molub-Alloy pastes are acceptable.
Yes, and this one matters. Paste reduces friction at the thread and under the bolt head, so a given target torque produces higher actual bolt tension than the same torque on a dry thread — over-tighten far enough and you yield the bolt. Fastener-engineering specifications publish dry-thread and lubricated-thread torque values separately: when you apply paste, use the lubricated-thread figure from your own bolted-joint specification. Do not derive it from the dry value with a rule of thumb on a high-tension joint.
Yes. Vasundhara Specialities Pvt Ltd is an authorised Castrol Industrial distributor (Andhra Pradesh), supplying Hyderabad, Telangana, Karnataka, Tamil Nadu and all of South India from our Bhimavaram stock point. Genuine Castrol Molub-Alloy assembly pastes — formerly sold as Castrol Optimol — with full manufacturer authorisation documentation provided on enquiry. For complete Castrol industrial portfolio see our Castrol catalogue.
Complete Castrol Industrial portfolio supplied by Vasundhara Specialities.
Send us your requirement, pack size and quantity — quote returned within 4 hours during business hours.
Request Quote WhatsApp UsWe supply Telangana customers directly from our IDA Mallapur warehouse in Hyderabad — genuine Castrol packs with batch COA, TDS and MSDS documentation. For Hyderabad-local service and multi-brand industrial supply, our Vasundhara Group company Vasundhara Performance Solutions is based in Hyderabad — call +91 99128 25442.