How to Build a Clean Box

We use the same techniques in Mushroom innoculation, working in a stream of clean air from a HEPA Filter. It is called Laminar Flow. Here are pictures of some we use in Mushroom Work. http://www.fungi.com/tools/airfilters.html The series 1 hood can be homebuilt. These people have filters for $90 for new ones. You work right in front of the filter in the clean airstream coming out. I would have no qualms about opening a HD inside a stream of clean air, I don't think there is a need for inert gas. Static electricity is a minor concern, you want to work in a grounded environment. More critical is working downstream of the drive in the airflow and moving slowly. A plexiglas shield may be handy. Here is one on Ebay if you are close, shipping would be expensive. http://cgi.ebay.com/HEPA-Filter-Fan-Unit-Laminar-Flow-Hood-Mushroom-Growing… Item number 290103957001 if the link breaks. This is a very high grade filter, Class 100. Used hoods are often used for mushroom work as they are often replacements for semiconductor fabs that are updated regularly. I used to get Filters and hoods from intel and sold them into the fungi market and/or the semiconductor market. Personally I use a homebuilt Laminar Flow Hood with a 12 inch by 12 inch HEPA filter (came off a Fujitsu drive line) with a small squirlcage blower that I can control the speed of. The goal is to maintain about 1 pound of pressure above ambiant between the blower and the intake of the filter. This generates the even flow through the filter. -- Paxton Hoag Astoria, OR USA