Making the Right Choices

When it comes to mixing and blending liquids, you’ll find getting the best results start with proper selection of the mixer itself. But making the right selection isn’t all it takes.

Proper positioning of your mixer and impeller can make a tremendous difference in terms of performance. Improper positioning leads to poorly mixed product.

Also, improper positioning can lead to excessive time to achieve target uniformity. Timing does vary based on application, but you can ensure your mixing process is as fast and efficient as possible with proper positioning mixer and impeller positioning.

Getting Mixed Results

Larger mixing vessels are often designed with a permanently positioned mixer. Still, there are many applications where the positioning of the mixer is open to significant adjustment. The positioning of a shaft's entry angle, in two axes, and the depth the impeller is positioned at, will contribute to different mixing results.

For instance, a clamp-mount mixer or lab stirrer are both capable of a wide range of mounting and impeller positions. Both can be used with a range of open lid vessels including those as small as pint or a quart – in the case of small lab stirrers – up to 55-gallon drums, or large open lid mixing vessels for clamp-mount mixers.

Our Recommendation

Our suggestion for optimal positioning of both clamp-mount mixers and lab stirrers is to offset the shaft and impeller to one side and extend toward the middle of the container – with the impeller positioned at 1.5 times the diameter of the impeller, off the bottom.


There may be a lot of trial and error involved when first attempting to get a good mix. Be prepared for time spent experimenting with speeds, positioning and times.

For pneumatic mixers, open the speed control valve slowly and increase gradually until desired mixing action is reached.

**Caution: Only operate mixer with the impeller submerged in the material (under load). Never allow air motor to “run free” at high speeds with no loads. Severe damage and/or injury could result.

The illustration below shows a typical operating angle for variable-position, top-mount mixers.

We’re here to help

For detailed recommendations on your mixing or dispersing applications, contact Fawcett Customer Service at 855-649-3569 or

For over half a century, Fawcett Mixing Equipment Specialists have looked at new ways to improve quality, maximize efficiency, and minimize safety concerns to find solutions for a variety of mixing applications. Let the mixing equipment specialists at Fawcett help you find the precise solution that works for your mixture requirements.