I live a few blocks from The Magic Elm skatting Rink going twoards McSherrystown .
I know where your at. Over by the school. I can't think of the name of it now. Is it Dalone?
anyhow, yup your in my old neck of the woods. my family lives near South West and my in-laws live out near the old West Manhiem elementary school.
How can you say 30"hg is a perfect vacumm???
30"hg your actual micron level can be 5,000+
When I intall equip the mfg requires your vacuum to reach 250 to 500 microns and hold for a set amout of hours (depending on the mfg.)
Are you just making fun of me, or are you really clueless?
30" hg is a perfect vacuum and is not possible. I believe the most that can be pulled with a vacuum pump is around 28"hg.
Do some searching on the internet. Your gauge may show you 30"hg, but the vacuum is realy no where near that.
Go read, and when you have a clue come back and tell us how close 30"hg is to a perfect vacuum.
But if your waiting for the vacuum to hold for hours, are you doing this in commercial or resi work? Or did it come out of the several refer reference manuals I HAVE SEEN AVAILABLE ON THE MARKET?
Don't think any body I know will would wait that long as fifteen minutes or twenty five is usually enough time to discover if you have a leak.