bulb whitening?

loving light · Nov 6, 2008

Hello,I just finished a Mag 85 useing,Mag 3d,3 Electrolumens battery holders(9 white top aa Duracell LSD rechargables),Borafloat lens,and a LOP cammed reflector.I was useing a potted wa1185 bulb(that I cleaned off with 91% denatured alcohol).Now that I have used this set up,I noticed that the bulb has a white film on the inside?I tried cleaning the bulb again so it is on the inside.Did I do something wrong,or is this just a freak accident?I do not want to try another bulb till I know that it is not something I did.The whited out bulb still works,but I know that I am looseing some light.Thanks for any help.:thumbsup:

Mark@LF · Nov 7, 2008

There is a leak somewhere on the bulb, it will probably burnt out soon.

loving light · Nov 7, 2008

Thank you for the response!Is this something that I did or is it a factory defect.Is this a common ocurance?Thanks again for telling me the reason of the whitening.Even with the bulb whitening I was impressed with the output(this was my first hotwire:D).

LuxLuthor · Nov 7, 2008

It's very hard to know for sure if this was a factory defect, or if leg pins were moved and slight crack introduced. In terms of frequency, I have used at least 150 small bulbs over the last years, and only had this happen to one WA bulb early on--so it's likely rare unless they dropped their QA standards.

fivemega · Nov 7, 2008

loving light said:
I was useing a potted wa1185 bulb(that I cleaned off with 91% denatured alcohol)

In order to pot the bulb in PR base, one pin must be bent to solder to center positive nipple and second pin to PR body. With this kind of physical stress on stiff bi pin bulbs, more likely bulb envelope gets tiny crack and inside gas slowly leaks out.
Wire terminal bulbs are more flexible and don't have this kind of problems.

loving light · Nov 8, 2008

Thank you for both of the detailed answers on "bulb whitening".I kinda figured that potted WA bulbs were not as good as unpotted,because they are not as popular and much harder to get.I will be getting a bi-pin bulb holder are there any differances in the ones being offered here on CPF,which would you guys recomend?Thanks for the help.