Air cleaner updateMy homemade air cleaner, which is also based on a furnace filter, still filters out microparticles after five months. But I only average about one day a week in the workshop.
Once the air cleaner has been running for a while, the 0.5-2.5 micron particle count in my shop will drop to around 50, so it's performing about as well as Daniel Chernoff's air cleaners.
I took the filter off to inspect. There is quite a lot of dust in there. I'm quite impressed. The filter in my furnace becomes much less effective at filtering out microparticles once it's visibly discoloured.
The reddish colour of the dust is probably from resawing some mahogany for Pat Hawley. That made for a lot of very fine dust.
This filter is a very thick filter cartridge that is meant to be replaced less often than regular furnace filters. I'm not sure if this filter is that much better or if it just performs better because I'm using it differently, but if I build another dust collector, I will definitely use one of these as the final filtering stage.
I think this filter is probably a better air cleaner filter than what is in most workshop air cleaners. Workshop air cleaners typically have three side by side bags that they pull air through, but the deep pleating of this filter probably makes for a larger surface area. Over two square meters (22 square feet) of filter surface. At $35, it's expensive for a furnace filter, but cheap compared to filter cartridges for air cleaners.
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