Impregnation Oil for SO16 — METADOP

A sintered self-lubricating bearing is, in effect, a rigid metal sponge. During manufacture the SO16 powder is compacted and sintered to leave the interconnected porosity characteristic of this material class — typically around 20-25% by volume — and METADOP is drawn into that capillary network. This works most completely under vacuum, which evacuates the trapped air so oil can be pulled deep into the pores; once charged, the pore structure behaves as a distributed oil reservoir sealed inside the bearing wall.

In operation, friction at the shaft raises the local temperature and the trapped oil expands faster than the surrounding metal. That differential thermal expansion, together with the hydrodynamic wedge formed as the shaft rotates, pushes a thin film of METADOP out to the running surface, separating shaft and bore with no external lubrication. When the bearing slows and cools, capillary action draws the oil back into the pore network, ready for the next cycle. The viscosity and anti-oxidant / anti-corrosion additive package of METADOP are chosen so this charge, release and reabsorb cycle repeats dependably over a long maintenance-free life in ISO 2795 / DIN 1850-style sintered bushes.

METADOP is applied to the porous material rather than press-fitted itself; the guidance below covers charging the oil and handling the fluid. The finished SO16 bush is then press-fitted into its housing by normal sintered-bearing practice, after which the impregnated oil does its work with no further lubrication.

• Vacuum impregnation (preferred): load clean, dry SO16 blanks into a basket, evacuate the chamber to draw air out of the pores, then flood with METADOP and release the vacuum so oil is forced into the evacuated capillaries. Gently warming the oil lowers its viscosity and speeds uptake.
• Hot-oil immersion: where vacuum equipment is unavailable, submerge the parts in warm METADOP and hold until bubbling from escaping air stops — the sign that the pores have filled.
• In-service re-oiling: a bush that has run dry can often be revived by soaking it in warm oil until it stops releasing bubbles, restoring much of the original charge.
• Finishing: wipe away surface excess so only the pore-held reservoir and a light running film remain; do not solvent-flush an impregnated part, as that strips the charge.
• Handling and storage: use clean, dedicated containers and keep the oil free of particulates and water; reseal after use and store cool, dry and away from strong oxidisers. Observe standard lubricant-handling PPE and disposal practice.
• Press-fit note: when fitting the finished SO16 bush, press on a hardened arbor and size to the housing bore rather than the ID — never ream an oil-impregnated bush, as reaming smears and seals the surface porosity.

Choose METADOP when you are impregnating or re-impregnating SO16 self-lubricating blanks specifically: its formulation is matched to that alloy matrix and to the machine-then-charge workflow SO16 blanks are built around. If your bearing is pressed or sintered from a bronze grade such as BP25 or an iron grade such as FP20, select the impregnation oil matched to that material instead, since the pore structure and duty of each matrix differ. The 1-litre pack is sized for workshop impregnation, prototype work and MRO top-ups; for continuous production charging, scale the quantity to your batch throughput. Where a certified viscosity grade, service-temperature window or oil-analysis certificate is required for a regulated application, request the supplier data sheet rather than relying on the typical class figures quoted here.