Nan's Nook : Archives : Misc Tek : 9er TekThis is the easiest, effective transfer box I know of. Even if you have to buy everything the cost should be under $35. There are several easy enhancements to this design, but this is a good basic box for beginners and takes about 20 to 30 minutes to throw together.
If your fan needs a power cord, buy a 99 cent extension
cord and cut the end off. It's far cheaper than buying a cord packaged
as such. Wire nuts are also very desirable to attach the cord to
the wires from the fan. No self respecting DIYer throws away
a device with the power cord still attached ;-)
In these photos you can see the dust mask on the outside, the fan on the inside, the "gloves" wrapped together and held with a clothes pin, and this box also features a hinged lid. The small section of plexiglas is taped in place and the door part is attached to the small section with a tape hinge.
That's all you need. Using a HEPA cartridge is better than a dust mask, but the dust mask setup works fine if you're on a tight budget.
Here you can see the fan mounted in the box. If you look hard, you can see through the translucent box, and see the dust mask taped over the intake hole on the outside.
2. Drill pilot holes to mount the fan to the inside of the box. A hot ice pick works well as a drill.
3. Cut out a hole inside the four screw holes for the fan to draw through. It should be at least 2" in diameter.
4. Mount the fan inside the box, blowing into the box. Seal with duct tape. Put the dust mask on the outside of the box over the draw hole and seal to the box with duct tape.
5. Stick your hand into the bottom corner of a trash bag. Now stick your arm thru' the arm hole as far into the glove box as you are likely to need to reach. Trim off the excess bag and use duct tape to attach the "glove" to the outside of the box around the arm hole. Repeat for the other arm hole.
To keep the gloves from billowing out like balloons when
you turn on the fan, you can sort of wrap them around each other and hold
with a clothes pin. You'll discover one of the nicer aspects
to the design is that with the fan running, the pressure presses the "glove"
against one's hands. This keeps the excess plastic from being
a hassle. (This type of "cheapo" glove doesn't
work if you suck air out of the box instead of the positive pressure design,
but the best reason to use positive pressure in the glovebox is that leaks
in the system are harmless. Filtered air pours out of them instead
of unfiltered air being sucked in through them.)
To use: Wipe down (or spray) the inside of the box and the under side of the plexiglas top with Lysol. Spray one glove heavily, then rub your hands (in the gloves) together to clean and sterilize the gloves. Place your materials in the box, lay the top in place, and turn on the fan. Allow it to run for a while (15 minutes is probably overkill). The positive pressure in the box means that filtered air is pouring out of every opening. The dust mask filter can be sprayed with Lysol as an extra precaution.
CAUTION: Using a knife to try to cut the plastic is very dangerous. The polypropylene that these boxes are made of is very tough and will crack without warning if you're using a lot of pressure with a knife. I ruined the first box and could have lost fingers the first time I built one of these. I tried to use a razor knife with a new blade and it did not work. Use a hair dryer and good, heavy duty scissors or tin snips. If you are not experienced with taking power supplies apart and general tinkering, please get someone who is to help with the wiring up of the fan.