Magnetic Separation Tube Rack 2 mL

This is a tube rack for magnetic bead separation experiments. After my first magnetic rack design (1), another colleague asked whether I could make something for their needs due to the outrageous cost of commercial products (2). So this is a really simple modification of the previous design to use 10×3 mm disk magnets (3) but customised for common 2 mL Eppendorf-style tubes they use in the lab (4).

Like the previous model, this has channels you slide the magnets into, and is made in two-parts with a screw down lid, with many benefits (reclaim the magnets, no magnet smashing, use any variant of 10×3 mm magnets, no magnet exposure to water, easy lid customisation, super-easy print). The hardest part is tapping the holes for 4-40 and finding a non-magnetic 4-40×1/2" screw (5). A spacer is included to secure the magnet in place but can also be scaled in size and placed underneath to raise the magnet if necessary.

I am quite proud of the lid design. Rather than tightly gripping the tube, which is subject to wild variations in printer and tube tolerances, the lid acts to support the hinge to prevent tube rotation. Combined with the base holes that stop lateral tube movement, it should be really easy to aspirate samples without disturbing them. This rack does not have the easy remove-the-tubes-to-vortex ability of the commercial option, but since it costs about $20 print and fill with magnets versus $900, I think most people will find the trade-off acceptable!

1. Original design
2. Outrageous!
3. Magnets!
4. Tubes!
5. Screws!

Please note that this has not yet been extensively tested in a wide range of separation experiments! It is up to individuals to confirm it works for their application. If you use this design in a scientific manuscript, I only ask that you please state the design was received from Dr. Adrian West, cite this webpage, and send me a link to your published paper!

Print Settings

Printer: Ultimaker S3

Rafts: No

Supports: No

Resolution: 0.1 mm

Infill: 40% cubic

Filament: BASF Ultrafuse PET Clear

This is a very easy print. The only consideration is that you will get the best results with a 0.4 mm nozzle and exactly 0.4 mm line width in your slicer, because the channel walls that hold the magnet are exactly 0.8 mm thick. Material is not important, but I like PET(x) for labware because of the superior chemical resistance. I went a bit nuts with high infill to make it nice and heavy, but you could probably go as low as 20%. Use a good adhesion aid and a brim because the geometry has a tendency to warp.