Why You Should Stay Away From MolyLube for Metal Marking

Why You Should Stay Away From MolyLube for Metal Marking

Jun 25th 2019

Five Reasons Why You Should Stay Away From Molylube for Metal Marking

We understand why some laser engravers might be tempted to experiment with Molylube for metal marking: at $10 per can, it is considerably less expensive than Enduramark.  However, we STRONGLY advise against the use of Molylube for laser-engraving purposes for the reasons we will explain below.

The Fundamental Difference Between Molylube and Enduramark

While Molylube consists primarily of molybdenum disulfide, Enduramark is based on molybdenum oxide.  If we thought using molybdenum disulfide was a good idea, we would use it. WHY? Because as a raw material, molybdenum disulfide is substantially less expensive than molybdenum oxide, and using it would significantly decrease our manufacturing costs. BUT...a deep understanding of the chemistry involved reveals some problematic aspects with molybdenum disulfide that we will detail next.

The Problems with Molybdenum Disulfide

(1) It contains sulfur, which produces sulfuric acid when burned in a laser.

Molybedenum disulfide contains sulfur, and when sulfur compounds are heated to high temperatures or burnt — as Molylube is when subjected to laser energy — the sulfur reacts with oxygen in the air and produces sulfur dioxide.  The sulfur dioxide then reacts further with oxygen and moisture in the air to produce sulfuric acid, ie. acid rain.

The acid rain we read about in the news is produced by the same process, but in that case, it is the combustion of sulfur-containing coal at power plants and sulfur-containing gasoline in cars that causes acidic by-products.

Because of the extremely acidic nature of sulfuric acid, it can cause extensive damage to all of the components inside your laser. You can get away with it for a while, but repeated exposure will corrode the belts, motors, exhaust-fan, and any other metal, plastic, and mirrored surfaces in the laser. 

EDUCATIONAL SIDE NOTE: Have you heard you shouldn't laser PVC-containing plastics? Guess what?? It is for the same reason described above except in the case of PVC, the acid produced is hydrochloric acid, ie. stomach acid.

(2) It's challenging to apply. 

Molylube contains several high-boiling solvents such as naptha and toluene, which are slow to evaporate, resulting in a surface that stays wet for some time after spraying.  This makes achieving a smooth, even layer without drip marks quite challenging. On the other hand, Enduramark dries almost instantaneously.

(3) It's difficult to wash off.

The thing that makes Molylube a great lubricant also makes it very messy and challenging to wash off.  Even with a sponge, you would have to expend some serious muscle power to remove all the unused material from the metal after lasering. 

(4) It does not produce a consistently reliable black mark. 

Some people say Molylube provides a good black mark. This has not been our experience.  Even if it did, the production of sulfuric acid as a by-product should be enough to change your mind.  

(5) It has not been tested for mark durability under a variety of extreme circumstances.

We have no idea how a mark with Molylube will hold up over time, but we are confident that a mark made with Enduramark is durable over time. In fact, we have tested Enduramark under severe conditions over long periods of time and have also published our results on our web site. Click Here for Durability Testing Results

Conclusion

Molylube is not specifically designed for metal marking, has application and post-laser cleanup issues, creates an inferior mark, has not been tested for durability, and causes long-term damage to lasers.  Although using Molylube saves money in the short-term, it is difficult to work with and incurs potentially catastrophic costs in damage to lasers over the long-term.