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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