I'm currently designing a closed tea strainer / egg made of stainless steel and testing a prototype made of polycarbonate plastic. The problem I'm facing likely has to do with the capillary effect - when I submerge my prototype repeatedly, the water seals the holes and causes it to float. The strainer itself isn't too large: 45mm x 45mm x 34mm to be exact with tightly packed holes, each with a diameter of 0.5mm.

My question is quite specific - how much larger would the diameter of the holes need to be for the water not to coat the holes? Would a different design (like lined cut outs instead of holes) be more sensible?

  • $\begingroup$ Does water wet polycarbonate at the same angle as steel? If the plastic is more hydrophobic it might resist the water in a different way. $\endgroup$ Mar 20 at 0:12