I was introduced to SPRI bead cleanup by Ethan Ford when doing NGS library preps and found it a really easy way to clean up many small volumes of DNA relatively easily and quickly. With the protocol for homebrew beads Ethan had, it was also a very cost effective method to purify PCR fragments and elute them in tiny volumes that were problematic with columns I was using.
Given I had leftover beads from my NGS preps, I set out to print myself a separator rack which seems to be merely a magnet that cost hundreds of dollars.
Due to me being a cheapskate this rack is not designed to fit typical 96well plates or strip-tubes. The spacing between tubes is designed to place them at the interface between the cheap 5mm Neodymium magnets I found on ebay for 10cent each. This seems to concentrate the magnetic flux there or something but makes the beads clump nice and tight in the tubes.
Technical
Non printed parts required:
10x5x3mm N50 Neodymium Magnets (n-1 required for each row, where n is number of tubes)
Print model, insert magnets, done!