Stephen

Got my new silicon o-rings a few days ago! Who knew that I could get so excited about an O-ring. After countless hours of scouring the internet and coming up empty, then talking to US-based O-ring manufacturers, who would be more than happy to do a custom mold for me for $500 (egad), I finally found an oversees suppler that I felt confident enough to do business with who actually had them in stock as a standard piece. I didn't feel too bad about farming this piece out... it is just an o-ring after all.

In any case, my surface tension leak check confirms that the much softer silicon does a fine job of sealing off against the challenging elliptical lens. I literally put about 6 or 7 drops of water on top of the lens until it looks like a "dome" of water is sitting on the lens (see pic). Then I let it sit like this for a day until the water evaporates, then look for any trace of leaking.

This elliptical lens (see pics) actually has a surface of very fine ridges, so the o-ring has to be soft enough to conform to these "peaks and valleys" and still make a good seal. With the "permanently" sealed build #1 version, I had to use a fine coat of flowable silicon on the oring before assembly to ensure no leaks. Now with the softer O-ring, I only need to use a thin layer of silicon grease to promote full seating into the lens cover. The side contacting the lens can remain "dry," which is what I was shooting for with the replaceable lens design. You can simply remove the lens cover, pop in a new lens, and screw it back down. No need to apply any grease.

The battery packs with the new balancing circuit boards are ready to ship. Got some cool new pics before they were heat-shrinked. A lot of attention to detail in these packs. All the cells are even super-glued to each other before shrink wrapping for extra rigidity.

Hope to get some definitive answers from the machine shops this week.