Easy Varroa Counter (300 Bees / CO2 & Alcohol)

Status: Work in Progress (Print test)

This is a preliminary design. I am currently remodeling the final parts to add some supports and printing prototypes to test real-world tolerances. The completed, tested version and actual print photos will be uploaded in the next few days!

Please note: I’m not a beekeeping expert! This model was designed based on my general knowledge / feedback, so feel free to share your suggestions if you see room for improvement.

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Unlike traditional alcohol wash methods that kill the sampled bees, this device uses CO₂ sedation (or powdered sugar): bees and mites are temporarily anesthetized, causing the mites to release their grip without harming the colony. Once inspected, the bees wake up within minutes and safely return to the hive.

Designed specifically for real-world field conditions, it features a 1/4-turn bayonet locking system with ribbed grip collars, allowing easy operation even while wearing thick beekeeping gloves.

Key Features

• Glove-Friendly 1/4-Turn Bayonet Lock: No tedious screw threads that bind with propolis or wax. Fast and secure twist-lock mechanism.

• Calibrated Separation Sieve (2.3 mm): Precision-dimensioned slots allow Varroa mites to drop through easily while safely retaining adult worker bees in the upper chamber.

• Universal CO₂ Needle Port: The top cap integrates a conical guide and passage hole compatible with standard bike/ball inflator needles connected to 16g CO₂ cartridges.

• High-Contrast Counting Grid: The bottom tray features concentric rings and quadrant lines in relief. (Print the tray in white with black embossed lines for instant mite counting).

• Dual-Method Compatible: Works perfectly with both CO₂ injection and powdered sugar roll testing.

Model Parts

1. VarroaBees_Lid — Top cap with conical needle inlet.

2. VarroaBees-Pad_Body — Main sample chamber with integrated 2.3 mm sieve and dual locking lugs.

3. VarroaBees_Bottom — Base collection tray with concentric counting grid.

Recommended Print Settings

• Filament: PETG or ASA / ABS (Recommended for outdoor UV resistance, summer hive temperatures, and easy cleaning with warm water/bleach). PLA is acceptable for testing, but PETG/ASA is advised for field durability.

• Layer Height: 0.20 mm

• Wall Loops / Perimeters: 3 to 4 (for solid bayonet lugs and walls)

• Infill: 15% - 20% (Gyroid or Grid)

• Supports: Supports are only needed on the top and bottom caps of the lock mechanism. However, I added a pre-supported version with a easy to cut part.

• Color Tip: Print the Counting Tray base in white filament, adding a manual filament change for the top 3 layers (concentric grid) in black for maximum contrast against dark reddish-brown mites.

How to Use (Step-by-Step)

1. Collect Sample: Assemble the bottom tray to the main chamber. Collect approximately 300 nurse bees (approx. 100 ml / 1/2 cup) from a brood frame (make sure the queen is NOT on the frame).

2. Lock & Sedate: Lock the top cap. Insert your CO₂ inflator needle into the top port and dispense a gentle burst of gas for 4–6 seconds until bee activity subsides.

3. Gentle Agitation: Gently shake the container in circular motions for 10–15 seconds to allow anesthetized mites to fall through the sieve.

4. Count Mites: Twist off the bottom counting tray and count the fallen mites over the grid.

   • Threshold calculation: Infestation Rate (%) = (Mites Counted / 300) × 100

   • (Note: More than 9 mites / 3% typically indicates a need for treatment).

5. Safe Release: Return the sleeping bees safely onto the top of the frames inside the hive. They will recover fully in a few minutes.

Thumbnail Note:

Cover image is a concept illustration generated with AI to showcase the final assembled look and function.

Changelog:

14/8/26
Added Supported Version
Added freecad project