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<p>Hi Lorenzo,</p>
<p>Thanks for your detailed feedback and this was along the lines of
my expectations. Have you or anyone else seen any self-contained
table-top baths that would fit on top of a wet-bench deck? Most
of what I've seen is deck-mount in a wet bench or a heater-chiller
designed to heat or cool a bath but not contain chemicals.</p>
<p>Does anyone do this safely without using an acid bath permanently
built into a wet bench? I'm guessing the answer is mainly no, but
I figured I'd check.</p>
<p>Thanks,</p>
<p>Nathanael</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 2026-04-19 9:35 a.m., Lorenzo
Palmiano wrote:<br>
</div>
<blockquote type="cite"
cite="mid:8654423F-B1DA-4D15-9A9F-6E2192427851@espie-electronic.com">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
Here are some tips, OSHA and SDS also breaks down all the safety
pre-cautions is 5 parts: engineering, handling, storage, PPE and
emergency response.
<div><br>
</div>
<div>
<p
style="margin: 0px 0px 12px; font-style: normal; font-variant-caps: normal; font-width: normal; line-height: normal; font-family: system-ui; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-variant-emoji: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">
At ~160 °C, phosphoric acid is highly viscous and near
boiling. Risks include increased splashing and bumping, higher
aerosol or acid mist generation, and severe combined thermal
and chemical burns from any contact.</p>
<p
style="margin: 0px 0px 12px; font-style: normal; font-variant-caps: normal; font-width: normal; line-height: normal; font-family: system-ui; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-variant-emoji: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">
<span style="font-weight: bold;">1. Equipment and Temperature
Control</span><br>
• Use only a temperature‑controlled acid bath or certified wet
etch bench<br>
• Do not use open beakers on generic hot plates<br>
• Verify bath temperature with an independent thermometer or
probe<br>
• Avoid overshoot above setpoint; local overheating increases
instability<br>
• Never leave heating unattended</p>
<p
style="margin: 0px 0px 12px; font-style: normal; font-variant-caps: normal; font-width: normal; line-height: normal; font-family: system-ui; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-variant-emoji: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">
<span style="font-weight: bold;">2. Water Exclusion (Zero
Tolerance)</span><br>
• Absolutely no DI water near the bath while hot<br>
• No wet wafers, tools, or condensation introduction<br>
• Do not add water to hot acid under any circumstances<br>
• Any water contact at this temperature can cause violent
splattering</p>
<p
style="margin: 0px 0px 12px; font-style: normal; font-variant-caps: normal; font-width: normal; line-height: normal; font-family: system-ui; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-variant-emoji: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">
<span style="font-weight: bold;">3. Required PPE at ≥160 °C</span><br>
• Chemical splash goggles AND full face shield (both required)<br>
• Acid‑resistant apron (front facing out)<br>
• Long acid‑resistant gloves with arm shields<br>
• Standard safety glasses alone are not sufficient<br>
• Do not use stained, wet, cracked, or poorly fitting PPE</p>
<p
style="margin: 0px 0px 12px; font-style: normal; font-variant-caps: normal; font-width: normal; line-height: normal; font-family: system-ui; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-variant-emoji: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">
<span style="font-weight: bold;">4. Positioning and Handling
Discipline</span><br>
• Never lean over the bath<br>
• Approach from the side, not directly from the front<br>
• Move slowly to avoid wave‑induced splashing<br>
• Treat all clear liquids as hot acid — never assume it is
water</p>
<p
style="margin: 0px 0px 12px; font-style: normal; font-variant-caps: normal; font-width: normal; line-height: normal; font-family: system-ui; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-variant-emoji: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">
<span style="font-weight: bold;">5. Ventilation and Airflow</span><br>
• Operate only with confirmed functioning exhaust<br>
• If airflow or power is lost, stop work immediately and leave
the area<br>
• Hot phosphoric acid fumes and mist present inhalation
hazards</p>
<p
style="margin: 0px 0px 12px; font-style: normal; font-variant-caps: normal; font-width: normal; line-height: normal; font-family: system-ui; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-variant-emoji: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">
<span style="font-weight: bold;">6. Emergency Readiness
(Before Starting)</span><br>
• Know the exact location of the eyewash and safety shower<br>
• Be prepared to cut heater power immediately if needed<br>
• In case of skin or eye exposure, flush with water for at
least 15 minutes and seek medical attention</p>
<p
style="margin: 0px 0px 12px; font-style: normal; font-variant-caps: normal; font-width: normal; line-height: normal; font-family: system-ui; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-variant-emoji: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">
<span style="font-weight: bold;">Bottom Line</span><br>
At ~160 °C, hot phosphoric acid must be treated as
near‑boiling corrosive material. Strict temperature control,
zero water exposure, full PPE, proper ventilation, and
disciplined handling are mandatory.</p>
<p
style="margin: 0px 0px 12px; font-style: normal; font-variant-caps: normal; font-width: normal; line-height: normal; font-family: system-ui; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-variant-emoji: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">
Please follow these precautions without exception.</p>
</div>
<div><br id="lineBreakAtBeginningOfSignature">
<div dir="ltr">Lorenzo P
<div>415.404.0565</div>
<div><a class="moz-txt-link-abbreviated" href="http://www.espie-electronic.com">www.espie-electronic.com</a></div>
</div>
<div dir="ltr"><br>
<blockquote type="cite">On Apr 19, 2026, at 7:23 AM, Nathanael
Sieb <a class="moz-txt-link-rfc2396E" href="mailto:sieb@4dlabs.ca"><sieb@4dlabs.ca></a> wrote:<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr">hot phosphoric acid etching in your facilities,
I would appreciate any safety or operational tips you have.
For us it would need to be a hot-plate process, and I want
to make sure we are taking a cautious approach before
allowing heating of phosphoric up to 160°C.</div>
</blockquote>
</div>
</blockquote>
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