Why is there a dimple in the glass of my DE greenpower

febisfebi

Well-Known Member
I was shocked to see, right on the middle of my beatiful new DE bulb, looks like a glass nipple/dimple. I thought at first it was a manufacturing defect, but the more I look at pictures of the bulb on other sites, it appears that they all have some sort of little round bump in the middle of the glass. What is this all about?
Thanks
 

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Jack Tambo

Active Member
Just guessing, but it looks like this is how they suck the air out of the bulb during manufacturing.
And then they close it by melting the glass.
 
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