The filter became ripe after another 11 months.  This year would be a full rebuild.

The filter lets you know it's in need of replacement when the apartment smells like a moldy school library.  After the wettest year on record & a very humid summer, a large nest of spiders had grown in the opposite corner from the inlet.  Some spiders escaped to other areas of the apartment.

A giant gnat invasion manifested on the other side of the filter.

After 5 hours of insecticide & washing, the new filter was installed.  Helas, the moldy filter smell was replaced by the smell of insecticide.  The early 2000's design featured many round edges in keeping with the times, making it impossible to seal.

New weather sealing was installed.  Weather sealing is not adhesive.  It has a mild adhesive for positioning it.  This roll burned $7.

The speed control features no fiducials so whether high is low is completely random.  This early 2000's design was the epitome of non manufacturability & non user servicability.  There were no user serviceable parts.  The wires had no connectors.  Parts don't automatically align themselves.  Much soldering made it somewhat serviceable.  It was designed to be manufactured only once.  As bad as times are, we're still better off than 2000.

Fully rebuilding it would take 3 days.  Cleaning the air inlets is another day.  Fully sealing the air passages is another day.

The question remanes of how to build a custom blower.  The 30055 was originally 110CFM.  The easiest solution is to extract the blower from another Hunter 30055 & put it in a custom enclosure.  There are Hunter 30055's on the fleebay for twice the price of when they were new.  They're more yellowed than this one & probably brittle.

The Ender 3 can print a 210mm diameter blower.  The bed is not square.  A concept print would take 11 hours & cost $5.

A thought experiment is whether the original 30055 enclosure would have been better at sealing the filter than the tape hack.  It originally got destroyed to save money on filters before discovering it needed a filter to avoid destroying the motor.  The days of cleaning it after using it without a filter for a year were the days.