Yes, this helps a lot.
Jim Marsico
EDO Corporation
1250 New Horizons Blvd.
North Amityville, NY 11701
631-630-5079
[log in to unmask]
-----Original Message-----
From: Kevin Glidden [mailto:[log in to unmask]]
Sent: Wednesday, April 11, 2007 11:32 AM
To: 'TechNet E-Mail Forum'; Marsico, James
Subject: RE: [TN] Water-break Test
I believe the intent is not to have the water draining from the surface
for
a minute, rather that the water stays in the thin film (placed
horizontally)
for 1 minute after the removal from the tank. If the water beads up
(like
on a waxed car) that indicates the contamination. This test is often
called
out for use on PCB surfaces prior to coating or even prior to bonding,
but
in a modified manner in that you can simply squirt a little DI water
from a
pipet onto the surface and see what happens - no dipping required.
Hope that helps,
Kevin
-----Original Message-----
From: Marsico, James [mailto:[log in to unmask]]
Sent: Wednesday, April 11, 2007 10:28 AM
To: [log in to unmask]
Subject: Re: [TN] Water-break Test
I've been looking at ASTM F22-02, Standard test method for Hydrophobic
Surface Films by Water-Break Test. The procedure is stated as follows:
"Withdraw the test surface, in a vertical position, from the container
overflowing with water."
The interpretation of results states:
"Surfaces tested ... shall be considered free of hydrophobic
contaminants by
this test method if the draining water layer remains as a thin
continuous
film over the surface for 1 min after withdrawal of the surface from the
overflow container. If hydrophobic contaminants are present, as
evidenced
by a formation of a discontinuous water film within 1 min after
withdrawal
of the surface from the overflow container, the length of time necessary
for
the water-break to occur is a rough indication of the degree of
contamination".
Now, a couple of questions. How can you expect all surfaces, assuming
that
they are contamination free, to remain wet and draining for 1 minute
after
removal from a tank? Should this be 1 minute of continuous rinse? What
if
all of the water drains off before the minute is up, is that a failure?
In
my case, when removed from the water bath, the water remains a
continuous
film for 15 seconds, after that, no more water remains.
Comments?
Jim Marsico
EDO Corporation
1250 New Horizons Blvd.
North Amityville, NY 11701
631-630-5079
[log in to unmask]
-----Original Message-----
From: Brian Ellis [mailto:[log in to unmask]]
Sent: Tuesday, April 10, 2007 2:40 AM
To: TechNet E-Mail Forum; Marsico, James
Subject: Re: [TN] Water-break Test
Before even trying to rely on the water break test, I suggest you may
care
to read the peer-reviewed paper I presented in Circuit World, Volume 35,
Number 4, 2005. pp 47-50, entitled "The Water Break Test".
This will explain that there are a number of fallacies involved, when
relying on such empirical methods. The main one is that the test will
succeed only on contaminated surfaces.
Brian
Marsico, James wrote:
> Hello Technet:
>
>
>
> We have an application where we have to etch a PTFE PWB in preparation
> for bonding. The etch is a commercially available sodium-containing
> solution. We're also expected to meet a water-break test prior to
> bonding. We're having trouble meeting the water-break test and was
> wondering if the two (etched PWB and water-break) are compatible. If
> so, what cleaning/rinsing could be performed after the etching to
ensure
> a water-break free surface?
>
>
>
> Thanks in advance,
>
>
>
> Jim Marsico
>
> EDO Corporation
>
> Amityville: 631-630-5079
>
> Bohemia: 631-218-7057
>
> [log in to unmask]
>
>
>
>
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