DIY laminar flow hood -- what I built, what I'd do differently
312 replies · Cultivation
Built my first flow hood last fall. Total cost was about $280 including the HEPA filter. Eight grain jar inoculations with zero contamination since. Here's what I built and what I'd do differently.
The blower choice is the most important decision. Underpowered blowers push air through the HEPA too slowly to maintain laminar flow. You want face velocity of at least 0.45 m/s across the HEPA face. Don't try to save $40 on the blower.
HEPA spec matters. True HEPA filters 99.97% of particles at 0.3 microns. Some filters marketed as 'HEPA-type' don't meet this spec. Buy from a supplier who can confirm the efficiency rating.
For anyone price-constrained: a good still air box achieves close to 99% contamination-free rates with practice. The difference between a quality SAB and a flow hood is real but smaller than marketing suggests.
309 more replies — forum posting coming soon.