You know what a reaction flask has to survive: days under heat, vacuum, and aggressive reagents, all at a volume where failure gets expensive fast. At-Mar Glass builds them for exactly that, spherical vessels and covers to 72 liters, blown and annealed in-house. Reach out to order or spec a build.
Three things separate reaction glass that lasts from glass that fails mid-run: the material, the closure system, and how temperature is controlled. Here’s how we approach each.
Every reaction flask glass body we form uses Type I borosilicate for its inertness and low thermal expansion. At production scale that matters more, not less, since a larger vessel stores more energy and stress, and a single weak point can end a costly, multi-day reaction.
Large reactions need several inputs at once, so we pair vessels with flanged, multi-neck reaction covers that clamp into a sealed system. A center neck plus side necks give you room for a stirrer, condenser, addition funnel, and probe without crowding a single opening.
A jacketed reaction flask adds a sealed outer wall for circulating coolant or heating fluid, holding a precise internal temperature across the run. We build jacketed vessels as specialized apparatus, sized and ported to match your circulator and process, since these are made to order rather than stocked.
Reaction chemistry doesn’t dictate a single shape. The right base depends on how you’re heating, stirring, and draining, so the same process might call for a sphere, a round bottom, or a flat base. We build across all three.
The spherical form is the heavy lifter for large-scale work. A chemical reaction flask in this geometry distributes heat and vacuum load evenly across a self-supporting curve, which is why our spherical vessels run from 2 liters to 72 liters without the stress points a flatter base introduces.
For smaller multi-neck work, a round bottom reaction flask often makes more sense than a large sphere. Our two-, three-, and four-neck round-bottom flasks cover that range with the joint sizes and neck counts most bench-scale reactions call for.
When a vessel needs to stand on its own or sit on a stir plate, a reaction flask flat bottom design earns its place. See our flat-bottom flasks for reactions that favor stability and open-bench handling over the even heating a curved base delivers.
When your process needs a vessel no format quite covers, that’s a custom glassware build. Bring the reaction, the constraints, and the equipment it has to fit, and our glassblowers work from your requirements to fabricate a vessel around the chemistry itself.
The spherical vessels and flanged covers below are our core reaction flask range, built for pilot and production-scale work. Each links to its live product page. Capacities and joint configurations vary, and anything outside this list is a standard custom order.
At this scale, who makes the glass matters as much as the spec. A 50-liter vessel is a significant investment, and the difference between suppliers shows up in the build quality, the price, and what happens when something needs fixing.
Large-format glass is genuinely hard to blow, which is why we keep it built and finished in-house at our Kennett Square facility. Decades of large-scale glassblowing experience go into every seam and joint, and none of it is handed to an outside shop.
A multi-liter reaction vessel shouldn’t cost more because it passed through a chain of distributors. Since the work stays on our benches, the price reflects the craftsmanship in the glass rather than layers of markup, even on the largest pieces we produce.
A cracked neck on a 22-liter vessel is expensive to replace and easy to underestimate. Our repair service can often restore or modify existing reaction glass, adding a port or neck to a vessel you already own, frequently within a weekend.
Questions we hear from labs speccing reaction glass for scale-up and process work. The answers focus on the decisions that actually shape what you should order rather than the textbook basics you already know.
The difference is the system, not just the vessel. A reaction flask is designed to integrate a multi-neck cover, thermal control, stirring, and metered addition into one sealed setup, so a reaction can run for hours or days under controlled, reproducible conditions without being opened.
More than people expect. Reaction flask chemistry is influenced by how evenly the vessel heats, how completely it drains, how well it holds vacuum, and how much surface area meets the contents. The wrong geometry can cost you yield, reproducibility, or a clean endpoint.
Broadly: spherical for the largest volumes and best heat-and-vacuum tolerance, round-bottom for multi-neck bench work, and flat-bottom where the vessel must stand unsupported. Volume, heating method, and whether the flask needs to sit on its own usually decide it.
Our stocked spherical vessels run from 2 liters to 72 liters, and covers come in 136 mm and 168 mm flange diameters. Beyond those, size is a custom conversation. We regularly build vessels to capacities and joint layouts no standard catalog offers.
Often, yes. Adding a neck, changing a joint, fitting a stopcock, or repairing a chip on an existing vessel is routine work for us. It’s frequently faster and cheaper than buying new, especially on large-format glass that takes real time to replace.
Whether you need a stock spherical vessel, a matched multi-neck cover, or a fully custom reaction flask for a process no catalog fits, we’re ready to build it. Reach out with your capacity, joints, and thermal needs, and we’ll get it into production.
