Finally released the HEPA/Carbon Air Scrubber. I’ll be adding at least a assembly video and maybe a very unscientific testing video. :-0
http://thingiverse.com/thing:1305485
Ooh, nice. I’ve been using Rod Laird’s scrubber for years, this looks like a nice way to get around the obscure respirator cartridge requirement.
@Ryan_Carlyle Thanks, this will move some air. ~190fpm @ 6vdc 
I couldn’t get the Neiko Gas Respirator to work in my testing unless I jacked the fan up to an ear piercing level, and even with that could only move about ~150fpm through that respirator.
I really wished I could get my hands on the respirator Rod uses…
Those filters Rod uses look supsiciously like the ones sold in TradeTools (aussie hardware store)
This is what I’ve been buying in the US: http://www.amazon.com/gp/product/B000XUF7RI
They’re a little big for Rod’s design, but I believe there’s a remix to make them fit.
@Ryan_Carlyle
Yep, those are the ones, from my testing they are doing VERY little scrubbing unless you are maxing out the motor or you’ve been able to seal almost every crack in your build chamber. Check out my R-621 testing video on YouTube. https://www.youtube.com/watch?v=RjgHV2-HvsE
In my testing of a FFCP, and sealing every opening (except where the extruders tubes and line go through) I could, It seems you need about 170fpm to get a negative pressure gradient inside the case. I even had to purchase the Makerbot top for my FFCP as the original is a hopeless case trying to get it sealed.
@Steve_M
I believe that’s exactly correct. What is your opinion on them?