It’s a Slippery Slope we weave.

The Lubricant story

laser weldA new customer recently complemented us on the great job we did repairing their bending section. The out-0f-round stiff bending section they sent us was gone and the repaired  “loose as a goose” bands that opened and collapsed from their own weight and gravity was returned to them. Also gone was the dirty moly-covered bending section and they received back a shiny-even- gleaming, bending section, absent nearly of all the moly. A little remains around the ears unless you really ‘pick’ it clean. But the customer questioned, “What happened to all the moly and what impact will it have on the free movement?


Let’s examine the  difference in the average bending section before and after a repair. The Original Equipment Manufacturer applies a dry lubricant molybdenum disulfide, nicknamed “moly“. It is important to get the finest/smallest particle size available as it comes in a range of sizes. When I did overhaul repairs at Olympus in the late 70’s, we applied moly to all of the internal elements by hand. We had a 16′ long by 2′ wide table with a half inch of moly covering the surface. With the bending section attached we started at the distal end and laid out all of the elements in order, no crossovers, and used scotch tape or light weight wire ties to keep them in place. Then we would use an artist’s paint brush to coat everything in moly. It wasn’t possible to use too much moly, only too little. The elements were inserted from the distal end into the insertion tube, making certain they then did not crossover any of the coil pipes. Every component was in it’s place.

Finally we would coat the angulation wires and feed them up through the coil pipes, but it never seemed like the metal components received enough moly to stay coated, so the bending section received one last dusting just prior to covering with the bending rubber. When the endoscope came back in for an overhaul, most of the moly had shifted depending on the scopes orientation during storage or deposited in the body due to fluid invasion. Endoscope overhauls were repaired in San Jose, CA in 1983. I was given special exemption to overhaul Bronchoscopes in the Baltimore branch until late 1985, the last person to do overhauls at the branch level.  This was due to the inexperience of technicians at the San Jose facility.


When I started my own flexible endoscope business in 1989 under the name of Fiber Tech Medical, I had more leeway to repair endoscopes differently than the manufacturer while still adhering to their standards and it didn’t matter if they shipped to Europe or stayed in the United States.  One of the first advances we made over the OEM‘s standard operating procedures was to pre-coat the bending section and angulation wires in a mix of moly and alcohol, then dried them under heat lamps. This assured a more uniform coat that would stay in place until placed under heavy load.  At some point the manufacturer began applying moly in an aerosol form, which means other surfactants are present to deposit lubricant and hold it in place.

Moly has many different uses, such as a mold release or anti-seize coating for bolts, however not all blends of moly are suitable as a lubricant. Many bending sections which come in for service possess a heavy layer of moly. Ultrasonic and detergents don’t touch it, felt buffing pads will not remove it, and 3M flap wheels remove it but leave scratches behind. The best remover is crushed walnut shells from a micro blaster. But what does it tell you when you have to use aggressive measures to remove it? How is it lubricating? All it appears to do is present a bumpy surface similar to splatter paint. Llojenn completes repairs by using crushed walnut shells, then silicone polishing wheels, (similar to what dentist use to polish teeth) and finish off with cotton pads and stainless steel polish to achieve a burr free glistening surface. Our surface has less coefficient of drag “prior to moly coating” than most moly coated bands from the OEM.

To prepare the bending section for installation , add the mesh and angulation wires, dilute and remove all flux residue, swish it around in a pan of moly Z powder and alcohol, then dry the component in a flameless method. And don’t forget to promote your repair procedures as “Better than the Manufacturers

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