{"product_id":"heathrow-ptfe-smooth-stir-bar","title":"Heathrow Scientific PTFE Smooth Stir Bar - 120894 Series | Alnico Magnet, Concave-Bottom Optimized, Pack of 10","description":"\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003eStandard octagonal stir bars are designed for flat-bottom vessels — but many laboratory flasks, round-bottom flasks, and specialty glassware have concave or curved bottoms where an octagonal bar rattles, wobbles, and loses magnetic contact at higher speeds. The Heathrow Scientific PTFE Smooth \u003cstrong\u003eMagnetic Stir Bar\u003c\/strong\u003e series is specifically designed for concave-bottom glassware: the smooth cylindrical profile maintains continuous contact with curved vessel floors, providing more stable coupling and quieter operation in the round-bottom and concave-bottom containers common in chemistry and biochemistry labs.\u003c\/p\u003e\n\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003eLike the Octagonal series, these bars use an Alnico magnet core encapsulated in chemical-resistant PTFE, withstand temperatures up to 250°C, and are autoclavable for sterile applications. Available in four sizes from 10×5mm through 35×8mm, sold in packs of 10.\u003c\/p\u003e\n\n\u003ch2 class=\"mb-2 mt-4 font-display font-semimedium text-base first:mt-0 md:text-lg [hr+\u0026amp;]:mt-4\"\u003eFeatures and Benefits\u003c\/h2\u003e\n\u003cul class=\"marker:text-quiet list-disc\"\u003e\n  \u003cli class=\"py-0 my-0 prose-p:pt-0 prose-p:mb-2 prose-p:my-0 [\u0026amp;\u0026gt;p]:pt-0 [\u0026amp;\u0026gt;p]:mb-2 [\u0026amp;\u0026gt;p]:my-0\"\u003e\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003eSmooth Profile Optimized for Concave-Bottom Glassware:\u003c\/strong\u003e The cylindrical smooth surface conforms better to the curved interior of round-bottom flasks, Erlenmeyer flasks with concave bases, and specialty vessels — maintaining continuous floor contact for stable, chatter-free rotation at high speeds.\u003c\/p\u003e\u003c\/li\u003e\n  \u003cli class=\"py-0 my-0 prose-p:pt-0 prose-p:mb-2 prose-p:my-0 [\u0026amp;\u0026gt;p]:pt-0 [\u0026amp;\u0026gt;p]:mb-2 [\u0026amp;\u0026gt;p]:my-0\"\u003e\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003eAlnico Magnet Core — Strong Permanent Coupling:\u003c\/strong\u003e Alnico magnet material provides superior coupling strength compared to ferrite alternatives — maintaining rotation lock in larger vessels and at higher speeds where weaker magnets decouple and spin out.\u003c\/p\u003e\u003c\/li\u003e\n  \u003cli class=\"py-0 my-0 prose-p:pt-0 prose-p:mb-2 prose-p:my-0 [\u0026amp;\u0026gt;p]:pt-0 [\u0026amp;\u0026gt;p]:mb-2 [\u0026amp;\u0026gt;p]:my-0\"\u003e\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003ePTFE Encapsulation — Inert, Chemical-Resistant Coating:\u003c\/strong\u003e Full PTFE coating is inert to virtually all laboratory chemicals including strong acids, bases, and organic solvents — protecting the magnet core and preventing ionic contamination of the stirred solution across the pH and chemical spectrum.\u003c\/p\u003e\u003c\/li\u003e\n  \u003cli class=\"py-0 my-0 prose-p:pt-0 prose-p:mb-2 prose-p:my-0 [\u0026amp;\u0026gt;p]:pt-0 [\u0026amp;\u0026gt;p]:mb-2 [\u0026amp;\u0026gt;p]:my-0\"\u003e\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003e250°C Maximum Temperature — Heated Stirring Compatible:\u003c\/strong\u003e PTFE stability to 250°C makes these bars safe for use on hot plate stirrers during heated mixing applications including titrations, reflux, dissolution testing, and thermally controlled reactions.\u003c\/p\u003e\u003c\/li\u003e\n  \u003cli class=\"py-0 my-0 prose-p:pt-0 prose-p:mb-2 prose-p:my-0 [\u0026amp;\u0026gt;p]:pt-0 [\u0026amp;\u0026gt;p]:mb-2 [\u0026amp;\u0026gt;p]:my-0\"\u003e\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003eAutoclavable for Sterile Applications:\u003c\/strong\u003e Withstands standard autoclave cycles for use in sterile cell culture, media preparation, and pharmaceutical manufacturing environments where contamination-free mixing conditions are required.\u003c\/p\u003e\u003c\/li\u003e\n  \u003cli class=\"py-0 my-0 prose-p:pt-0 prose-p:mb-2 prose-p:my-0 [\u0026amp;\u0026gt;p]:pt-0 [\u0026amp;\u0026gt;p]:mb-2 [\u0026amp;\u0026gt;p]:my-0\"\u003e\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003eFour Sizes, Pack of 10 — Versatile Coverage:\u003c\/strong\u003e The 10×5mm through 35×8mm range covers small vials and test tubes up to large 3L vessels — and the pack of 10 provides immediate replacement stock for labs that go through stir bars regularly.\u003c\/p\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 class=\"mb-2 mt-4 font-display font-semimedium text-base first:mt-0 md:text-lg [hr+\u0026amp;]:mt-4\"\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eProperty\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSKU Series\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e120894 (10×5mm), 120895 (25×8mm), 120896 (30×8mm), 120897 (35×8mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBrand\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eHeathrow Scientific\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMaterial\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePTFE encapsulation \/ Alnico magnet core\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eShape\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSmooth cylindrical (optimized for concave-bottom vessels)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eColor\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eWhite\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePack Size\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePack of 10\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMax Temperature\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e250°C\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAutoclavable\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCountry of Origin\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eChina\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2 class=\"mb-2 mt-4 font-display font-semimedium text-base first:mt-0 md:text-lg [hr+\u0026amp;]:mt-4\"\u003eLaboratory Applications\u003c\/h2\u003e\n\u003cul class=\"marker:text-quiet list-disc\"\u003e\n  \u003cli class=\"py-0 my-0 prose-p:pt-0 prose-p:mb-2 prose-p:my-0 [\u0026amp;\u0026gt;p]:pt-0 [\u0026amp;\u0026gt;p]:mb-2 [\u0026amp;\u0026gt;p]:my-0\"\u003e\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003eRound-Bottom Flask Stirring in Chemistry:\u003c\/strong\u003e Use in round-bottom flasks for organic synthesis, reflux reactions, and distillation setups where the smooth profile maintains reliable floor contact in the curved vessel bottom — eliminating the wobble that octagonal bars produce in round-bottom geometry.\u003c\/p\u003e\u003c\/li\u003e\n  \u003cli class=\"py-0 my-0 prose-p:pt-0 prose-p:mb-2 prose-p:my-0 [\u0026amp;\u0026gt;p]:pt-0 [\u0026amp;\u0026gt;p]:mb-2 [\u0026amp;\u0026gt;p]:my-0\"\u003e\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003eErlenmeyer Flask \u0026amp; Conical Vessel Mixing:\u003c\/strong\u003e The smooth profile is well-suited to the slightly concave bottom geometry of Erlenmeyer flasks used in titrations, culture media preparation, and standard chemistry protocols.\u003c\/p\u003e\u003c\/li\u003e\n  \u003cli class=\"py-0 my-0 prose-p:pt-0 prose-p:mb-2 prose-p:my-0 [\u0026amp;\u0026gt;p]:pt-0 [\u0026amp;\u0026gt;p]:mb-2 [\u0026amp;\u0026gt;p]:my-0\"\u003e\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003ePharmaceutical \u0026amp; Biochemistry Research:\u003c\/strong\u003e Mix enzyme reactions, protein solutions, and pharmaceutical formulations in concave-bottom reaction vessels where a stable, low-vibration stir bar is required to prevent foam formation and protect shear-sensitive samples.\u003c\/p\u003e\u003c\/li\u003e\n  \u003cli class=\"py-0 my-0 prose-p:pt-0 prose-p:mb-2 prose-p:my-0 [\u0026amp;\u0026gt;p]:pt-0 [\u0026amp;\u0026gt;p]:mb-2 [\u0026amp;\u0026gt;p]:my-0\"\u003e\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003eHeated Reaction Mixtures:\u003c\/strong\u003e The 250°C temperature tolerance makes these bars the correct choice for hot plate-stirred reactions including recrystallizations, titrations, dissolution testing, and synthesis protocols requiring simultaneous heat and agitation.\u003c\/p\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 class=\"mb-2 mt-4 font-display font-semimedium text-base first:mt-0 md:text-lg [hr+\u0026amp;]:mt-4\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003eWhen should I use Smooth stir bars instead of Octagonal Pivot Ring bars?\u003c\/strong\u003e\u003cbr\u003eUse Smooth bars (120894–120897) in round-bottom flasks, Erlenmeyer flasks, and any vessel with a concave or curved bottom — the smooth profile maintains consistent floor contact in curved geometries. Use Octagonal Pivot Ring bars (120547–120552) in flat-bottom beakers, crystallizing dishes, and vessels with flat floors where the pivot ring and octagonal turbulence characteristics are most effective.\u003c\/p\u003e\n\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003eWhat size smooth stir bar should I use for my flask?\u003c\/strong\u003e\u003cbr\u003eFor flasks under 250mL, use 10–25mm bars. For 250–500mL flasks, use 25–30mm bars. For 500mL–2L flasks, use 30–35mm bars. As a general guideline, choose a bar that is approximately 1\/3 to 1\/2 the vessel's internal diameter at the bottom.\u003c\/p\u003e\n\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003e\u003cstrong\u003eAre the Smooth bars compatible with the Heathrow Scientific Magnetic Induction Stirrer?\u003c\/strong\u003e\u003cbr\u003eYes. All Alnico-core PTFE stir bars are compatible with the Heathrow Scientific Magnetic Induction Stirrer (120584\/120585) and all standard motor-driven magnetic stirrer platforms.\u003c\/p\u003e\n\n\u003ch2 class=\"mb-2 mt-4 font-display font-semimedium text-base first:mt-0 md:text-lg [hr+\u0026amp;]:mt-4\"\u003eQuality Assurance\u003c\/h2\u003e\n\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003eHeathrow Scientific PTFE stir bars are manufactured with sintered Alnico cores and full PTFE encapsulation under rigorous quality standards. Each production lot is inspected for coating uniformity and dimensional accuracy to ensure reliable, contamination-free performance in concave-bottom laboratory glassware.\u003c\/p\u003e\n\n\u003ch2 class=\"mb-2 mt-4 font-display font-semimedium text-base first:mt-0 md:text-lg [hr+\u0026amp;]:mt-4\"\u003eAcademic and Institutional Pricing\u003c\/h2\u003e\n\u003cp class=\"my-2 [\u0026amp;+p]:mt-4 [\u0026amp;_strong:has(+br)]:inline-block [\u0026amp;_strong:has(+br)]:pb-2\"\u003eLabSupplies.com offers tiered quantity pricing for academic and research institutions. As an authorized dealer, we ship directly from USA inventory.\u003c\/p\u003e","brand":"Heathrow Scientific","offers":[{"title":"10 × 5 mm","offer_id":48073602072808,"sku":"120894","price":40.0,"currency_code":"USD","in_stock":true},{"title":"25 × 8 mm","offer_id":48073602105576,"sku":"'120895","price":52.2,"currency_code":"USD","in_stock":true},{"title":"30 × 8 mm","offer_id":48073602138344,"sku":"'120896","price":72.9,"currency_code":"USD","in_stock":true},{"title":"35 × 8 mm","offer_id":48073602171112,"sku":"'120897","price":83.7,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0694\/5361\/1240\/files\/unnamed_e9e5303d-0e85-49b6-b35f-e9fcff30ff1f.jpg?v=1771689027","url":"https:\/\/labsupplies.com\/products\/heathrow-ptfe-smooth-stir-bar","provider":"LabSupplies.com","version":"1.0","type":"link"}