This will NOT work with a magnetic stir system.

Inserting a 50mm glass funnel upside down in pint and quart jars allows the use of a 4 watt bulb for stirring and reduces heat soak while channeling and increasing the velocity of thermal updraft. Spacers made by clamping plastic tubing sections cut lengthwise onto the rim of the funnel allow circulation.

This has been done for you as:

6] "Thermal Updraft Channeler " for pints and quart batches [aka Inverted Funnel] [lab glass] [Enhances stirring in taller containers and concentrates ions for fast stabilization] This will NOT work with a magnetic stir system.$6

Plastic funnels float but can be weighted down with a large stainless steel washer or a copper wire loop with the insulation left on and the ends sealed with silicon. [Exposed copper will attract particles and oxides] It might be OK to use a zinc dipped steel washer. [Not tested]

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