Quote:
Originally Posted by sand_man
(No tone implied here) So which one to use? None? What's your recommendation?
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With most things in the physical world, there are compromises.
Engine building is no different.
We give up compression for driveability and we sacrifice weight for cost. We sacrifice horse power for torque.
The question is always "what is the trade off?"
In the graph above (from Dow research BTW.) you see only one criteria.
During the development of Dow 55, the engineers set the criteria on multiple levels.
They wanted to enhance the sealing properties as well as enhancing the life of an given o-ring while providing lubricant for installation.
To these ends, they decided (correctly I believe) to enhance the sealing properties by expanding the o-ring after installation.
They were also interested in enhancing crush resistance of a given o-ring over time and heat cycles.
They accomplish these goal by slightly changing the o-ring with a propitiatory chemical formula.
This chemical change in no way degrades the o-ring in a way that causes it to deteriorate. Much to the contrary, we have found over years that the o-rings seem more elastic after long periods with the Dow55 than without.
To my knowledge, no other lubricant offers these properties.
If we were, let's say building a slingshot we would probably choose a different treatment for the elastic material but I guess if I were building a sling shot I might solicit the advise of Dennis the Menace for his anecdotal expertise.