Drilling an older 90

[Slick Fork]

Do a search on here for "tempered glass polarized" and on one of the search results is the details for a real easy 30 second test you can do to see if the glass is tempered or not.

Check every pane that you plan to drill. Some tanks will be mixed with one or more pane being tempered and the others not.

[scherzo]

I've tried the polarized lens thing but it is really tough to see if I have the correct lighting.

I've had some people tell me that it doesn't always work either.

I guess it'll have to be an adventure.