Hi Jim,
I was more concerned with structural integrity than air leaks with my
posting.
I'm building a small sub out of fiberglass / epoxy & will be needing to
thoroughly
test it.
From what I gather you can't pull more than an absolute vacuum because
there's
no air for your pump to push out.
I'm wondering if you filled your hull up with water whether a high pressure
water pump
could create a negative pressure in the hull. Or am I barking up the same
tree.
Alan
----- Original Message -----
Sent: Wednesday, January 19, 2011 4:04
PM
Subject: Re: [PSUBS-MAILIST] Pressure
testing with a vacuum pump
Alan,
Still you can take it down to about 30 feet without ever
leaving your shop. If it doesn't leak air at that pressure differential
that's good. If it does leak, you've only got air (or a leak
detector) instead of dirty water or salt water into the
defect.
So this begs two questions:
1. What's the best product and/or procedure
for locating a small leak flowing from the outside of a vessel to
the inside?
2. Would it be better to try to seal the hatch and
pressurize the vessel on the inside to detect air leaking to the
outside? That's putting the higher pressure on the "wrong" side of the
hatch/canopy.
Jim T
In a message dated 1/18/2011 8:20:05 P.M. Central Standard Time,
alanjames@xtra.co.nz writes:
Thanks
everyone for clearing that up, I was thinking that if you had a pump that
could produce 250 psi & it's sucking from somewhere, that you could
attach it's intake to a hull & produce a negative 250 psi pressure.
Have done a bit of "Googling" with your direction & have sought of
got my head round it. Darn! it seemed a lot easier option than dropping
my hull down a deep lake on a long rope. Regards Alan
-----
Original Message ----- From: "Jens Laland"
<laland@artematrix.org> To:
<personal_submersibles@psubs.org> Sent: Wednesday, January 19, 2011
1:19 PM Subject: Re: [PSUBS-MAILIST] Pressure testing with a vacuum
pump
> This one I find quite useful with regards to measuring
vacuum, ref > >
http://traktoria.org/files/instrumentation/vacuum/Pressure_Conversion_Table1.pdf >
> Best regards, > Jens Laland > > >
> > >
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