Overhead Stirrers

Shop used and available-to-source overhead stirrers for laboratory mixing applications. mLab Supply helps laboratories source equipment from manufacturers including IKA, Heidolph, Caframo, Scilogex, and OHAUS. Overhead stirrers use a motor-driven shaft and impeller for direct mechanical mixing and are commonly evaluated based on the application, vessel, material properties, and required mixing performance. Used equipment configurations vary, so stands, clamps, shafts, impellers, and other accessories should be verified for each unit. Browse available listings or request a quote for help sourcing a specific overhead stirrer.

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<h2>How to Choose an Overhead Stirrer</h2>
<p>Selecting an overhead stirrer starts with understanding the application and the properties of the material being mixed. Key considerations include the vessel type and geometry, the viscosity and density of the material, required mixing duration, and whether the process demands gentle blending or more vigorous agitation. Shaft and impeller selection should be matched to the vessel geometry and material compatibility requirements. Mounting configuration and available workspace should also be evaluated before selecting a unit, as overhead stirrers require stable support and adequate clearance above the vessel.</p>

<h2>What Is an Overhead Stirrer?</h2>
<p>An overhead stirrer is a laboratory instrument that uses a motor-driven shaft and attached impeller to mix liquids directly from above the vessel. Unlike magnetic stirrers, which rely on a rotating magnetic field and a stir bar inside the vessel, overhead stirrers drive the mixing element mechanically through a motor mounted above the sample. This configuration makes overhead stirrers well suited for applications where the volume, viscosity, or mixing requirements exceed what magnetic stir bars can accommodate.</p>

<h2>Overhead Stirrers vs Magnetic Stirrers</h2>
<p>Overhead stirrers and magnetic stirrers are both used for liquid mixing in laboratory settings, but they operate differently and are suited to different applications. Magnetic stirrers use a rotating magnetic field to spin a small stir bar placed inside the vessel, making them compact and convenient for smaller volumes and lower-viscosity materials. Overhead stirrers use a motor-driven shaft inserted into the vessel from above, allowing direct mechanical mixing of larger volumes, denser materials, and samples where a stir bar would be insufficient or impractical. When mixing requirements exceed what a magnetic stirrer can reliably handle, an overhead stirrer is typically the appropriate choice.</p>

<h2>Overhead Stirrers vs Homogenizers</h2>
<p>Overhead stirrers and homogenizers both involve mechanical mixing, but they serve distinct purposes. Overhead stirrers are designed for bulk mixing—blending liquids, preparing solutions, suspending solids, or maintaining uniformity in a vessel over time. Homogenizers are designed to reduce particle size, disrupt cells, disperse immiscible liquids, or achieve fine emulsification, often at much higher operating speeds and with specialized probe geometries. If the goal is mixing a solution or suspension at the bulk level, an overhead stirrer is typically the appropriate instrument. If the goal is particle size reduction, cell disruption, or emulsification, a homogenizer would be the correct choice.</p>

<h2>Selecting Shafts and Impellers</h2>
<p>Shaft and impeller selection is an important part of configuring an overhead stirrer for a specific application. Impeller geometry affects flow pattern, mixing efficiency, and suitability for different material types. Shaft length must be compatible with the vessel depth, and shaft material must be compatible with the chemicals or solvents being mixed. Used overhead stirrers may or may not include the original shaft, impeller, or other accessories. Buyers should confirm which components are included with each unit and verify compatibility with their specific vessel and application before purchase.</p>

<h2>Popular Manufacturers and Models</h2>
<p>mLab Supply sources used overhead stirrers from a range of laboratory equipment manufacturers. Common models that may be available include the following.</p>

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<h3>IKA</h3>
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<li>EUROSTAR 20 digital</li>
<li>RW 20 digital</li>
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<h3>Heidolph</h3>
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<li>Hei-TORQUE 100</li>
<li>Hei-TORQUE Precision 100</li>
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<h3>Caframo</h3>
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<li>BDC1850</li>
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<h3>Scilogex</h3>
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<li>OS-40 Pro</li>
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<h3>OHAUS</h3>
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<li>ACHIEVER 5000</li>
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<h2>Buying Used and Refurbished Overhead Stirrers</h2>
<p>When evaluating used overhead stirrers, buyers should assess motor condition and operation, chuck condition and secure engagement with the shaft, the function and accuracy of speed controls, the condition of any mounting hardware, the electrical configuration and voltage compatibility for the intended facility, and general cosmetic condition. The exact configuration of each unit, including which accessories are present, varies and should be confirmed before purchase. mLab Supply does not represent used units as tested, refurbished, or calibrated unless explicitly stated for a specific listing.</p>

<h2>Configuration and Included Accessories</h2>
<p>Overhead stirrer configurations vary by unit. Stands, clamps, chuck adapters, shafts, impellers, paddles, propellers, and other accessories may or may not be included with a used unit. Buyers should not assume that any accessory is included unless confirmed for the specific listing. Verifying the included configuration before purchase is recommended, particularly when compatibility with existing vessels or processes is required.</p>

<h2>Common Applications</h2>
<p>Overhead stirrers are used across a range of laboratory mixing tasks, including:</p>
<ul>
<li>Buffer preparation</li>
<li>Media preparation</li>
<li>Solution mixing</li>
<li>Reagent preparation</li>
<li>Formulation research</li>
<li>Suspension mixing</li>
<li>Laboratory process development</li>
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<h2>Laboratory and Facility Planning</h2>
<p>Overhead stirrers require adequate workspace above and around the vessel to allow safe motor mounting and shaft clearance. A stable support stand and secure clamp are important for safe operation, particularly with larger vessels. Electrical requirements should be confirmed against the available supply in the lab, as voltage and frequency requirements vary by model and region. Setup requirements vary by unit and application and should be evaluated before installation.</p>

<h2>Procurement and Sourcing</h2>
<p>mLab Supply can help identify used, surplus, or available-to-source overhead stirrers where offered. For specific model requests or sourcing inquiries, buyers can submit a quote request and the mLab Supply team will assist in identifying available options. Availability varies and is not guaranteed for any specific model or configuration.</p>

<h2>Related Laboratory Equipment</h2>
<p>Laboratories sourcing overhead stirrers may also be evaluating related mixing and agitation equipment. mLab Supply carries used and available-to-source equipment in the following categories:</p>
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<li><a href="/collections/hot-plates-magnetic-stirrers">Hot Plates &amp; Magnetic Stirrers</a></li>
<li><a href="/collections/homogenizers-and-bead-mills">Homogenizers and Bead Mills</a></li>
<li><a href="/collections/orbital-shakers">Orbital Shakers</a></li>
<li><a href="/collections/incubator-shakers">Incubator Shakers</a></li>
<li><a href="/collections/vortex-mixers">Vortex Mixers</a></li>
<li><a href="/collections/bioreactors-and-fermenters">Bioreactors and Fermenters</a></li>
</ul>
<p>To request a quote for any overhead stirrer or related equipment, visit the <a href="/pages/request-a-quote">Request a Quote</a> page.</p>

<h2>Frequently Asked Questions</h2>

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<h3>What is an overhead stirrer?</h3>
<p>An overhead stirrer is a laboratory instrument that uses a motor mounted above a vessel to drive a shaft and impeller for direct mechanical mixing of liquids.</p>
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<h3>What is an overhead stirrer used for?</h3>
<p>Overhead stirrers are used for a range of liquid mixing tasks including buffer preparation, media preparation, solution mixing, reagent preparation, formulation research, suspension mixing, and general laboratory process development.</p>
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<h3>When should I use an overhead stirrer instead of a magnetic stirrer?</h3>
<p>An overhead stirrer is typically the appropriate choice when the volume, viscosity, or density of the material exceeds what a magnetic stir bar can reliably handle, or when the vessel geometry makes magnetic stirring impractical.</p>
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<h3>What should I check when buying a used overhead stirrer?</h3>
<p>Key items to evaluate include motor condition, chuck condition and engagement, function of speed controls, mounting hardware condition, electrical configuration and voltage compatibility, and overall cosmetic condition.</p>
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<h3>Are shafts and impellers included with used overhead stirrers?</h3>
<p>Not necessarily. Shaft and impeller inclusion varies by unit. Buyers should confirm which components are included with each specific listing before purchase.</p>
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<h3>Are stands and clamps included?</h3>
<p>Stands, clamps, and other mounting hardware are not guaranteed to be included with used overhead stirrers. Configuration varies by unit and should be confirmed for each listing.</p>
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<h3>How do I choose an overhead stirrer for my application?</h3>
<p>Selection should be based on the application, vessel type and geometry, material properties, required mixing intensity and duration, and shaft and impeller compatibility. Workspace and mounting requirements should also be considered.</p>
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<h3>What is the difference between an overhead stirrer and a homogenizer?</h3>
<p>Overhead stirrers are designed for bulk mixing—blending solutions, preparing media, or maintaining suspension. Homogenizers are designed for particle size reduction, cell disruption, or emulsification. These are distinct instruments suited to different tasks.</p>
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<h3>Can mLab Supply source a specific IKA or Heidolph overhead stirrer?</h3>
<p>mLab Supply can assist with sourcing specific models where available. Submit a request through the <a href="/pages/request-a-quote">Request a Quote</a> page and the team will follow up on availability.</p>
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<h3>Are used overhead stirrers always refurbished?</h3>
<p>No. Used overhead stirrers offered through mLab Supply are not represented as refurbished or calibrated unless explicitly stated for a specific listing. Condition and configuration vary by unit.</p>
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<h3>How should I evaluate the configuration of a used overhead stirrer?</h3>
<p>Review the specific listing carefully for information on included components. Contact mLab Supply to confirm configuration details before purchase, particularly when compatibility with existing vessels or processes is required.</p>
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<h3>What information should I provide when requesting a quote?</h3>
<p>When submitting a quote request, it is helpful to include the specific model or brand you are looking for, your application or mixing requirements, vessel size if known, and any preferences regarding included accessories or configuration.</p>
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