In a message dated 02/18/2000 9:24:56 AM US Eastern Standard Time,
[log in to unmask] writes:

>
>  I wonder if anyone has any ideas about removing HASL from B25A coupons.
> Someone here goofed and ordered our test coupons with HASL instead of bare
> copper - you can't get the staff you know!
>
>  So, as it will take some time - and money! - to get these replaced I
thought
> I would put this to the experts.
>

Graham,
This is one of those Can I - Yes, Should I - No questions.  B25A boards are
cheap and you will put more money into stripping the tin-lead than you will
for new boards.  In quantity, these boards only cost $3-4 each (at least when
I buy them for our inventory here).

Second, the SIR will be degraded by about half a decade, perhaps more,
depending on the porosity of the mask and laminate.  I presume you are
looking at qualifying a coating or mask, which is what that board is used
for.  If your mask or coating fails the SIR test, was it a fault in the
material being qualified or an effect of the stripping?  I suggest that you
run a few virgin bare copper B25A boards and a few stripped B25A boards
through a few days of the test environment.  If you see no appreciable
difference between the two, then use what you have.  Without this check, you
will never know.

I have Gerber files for the B25A if you are interested and can e-mail them to
the fabricator of your choice, if you wish.  I don't know if you have a local
source for these boards, as I do.

Doug Pauls
CSL

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