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<p>Mario,</p>
<p>Is there a particular reason you absolutely need Piranha? I made
the switch to RCA in our teaching cleanroom after getting tired of
cleaning up spills. Even a few drops burn leave burn marks. RCA is
fairly dilute (5:1/6:1) and the use temperature is only 70 C.
Also, adding peroxide isn't as fraught. No matter how "well
trained" the students are, the Piranha preparation process is
unforgiving. Hazards to users, chemical waste and disposal risk (I
don't have neutralization capabilities) drove my decision making.</p>
<p>Prashant</p>
<div class="moz-cite-prefix">On 11/17/2025 10:48 AM, Beaudoin, Mario
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:5390d1e8-57de-4909-8900-5168989ab124@physics.ubc.ca">
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<p>Dear Labnetwork,</p>
<p>As many labs do, because of safety concerns for the students, I
banned the use the real pirahna etch in favor of Purestrip
(Transene version of nanostrip). The problem I have is that the
solution eventually leaks from the bottle. I have heard of
others mentioning this also. </p>
<p>I am now thinking of revising this policy and going back to old
pirahna, despite the issues with safety and aging H2O2.</p>
<p>Anyone have comments?</p>
<p>Mario</p>
<div class="moz-signature">-- <br>
<img src="cid:part1.3RNpK0vD.7A01NJAU@ucsb.edu" border="0"
class=""></div>
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<pre class="moz-signature" cols="72">--
Prashant Srinivasan,
Teaching Cleanroom Engineer
Electrical & Computer Engineering
University of California, Santa Barbara
Santa Barbara, California 93106
<a class="moz-txt-link-freetext" href="https://www.ece.ucsb.edu/department-resources/electronics-shop/tcr">https://www.ece.ucsb.edu/department-resources/electronics-shop/tcr</a></pre>
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