Admin (Admin)
 Posted on Thursday, August 23, 2001  11:52 am: 

Here's a small quote from Rush Wayne's Peroxi Manual Volume II, It involves using Grey Cardboard instead of agar!!! Here are the detailed steps for making cardboard plates. Note that you can also use small jars in place of Petri dishes. 1) Measure about 100 mls. of tap water into a small jar. 2) For nutrients, , measure another 100 mls. of tap water into a second jar and add one drop of ordinary soy sauce to the water, and a quarter teaspoon (1.25 mls.) of molasses or light malt powder. 3) Find some gray cardboard, the thicker the better, preferably gray on both sides. Trace a Petri plate onto the cardboard with a pencil and cut out several disks to fit into your plates. 4) Weigh one of your disks and record the weight. Multiply this weight by a factor of 1.3 as a rough guide (you may need to experiment with the amounts here), and add the resulting weight of tap water or nutrient solution to each disk in its Petri plate. (Remember, 1 ounce of water equals 28.35 grams; one gram equals one milliliter.) Example: Suppose my disks weighed 0.17 ounces each. Multiplying 0.17 by 1.3, I get 0.22 ounces. There are 28.35 grams in an ounce, so 0.22 ounces x 28.35 equals 6.3 grams. That means I'll add 6.3 milliliters of solution to each disk. 5) Close up the disks in the plates, and let the water or nutrient solution soak in. 6) Pressuresterilize the jar of plain water, and the Petri plates with moistened newsprint disks inside, for 10 minutes at 15 psi (allowing the cooker to equilibrate steam for 10 minutes before putting on the pressure regulator). 7) Cool the cooker, and remove the plates and jar of plain water. 8) When the water has cooled, add 3.3 mls. 3% peroxide to the jar, using a pasteurized pipette, to give you a final concentration of about 0.1% peroxide in sterile water. 9) Add about one third of the initial weight of the cardboard as 0.1% peroxide to each disk. Let the solution soak completely into the disks. They are now ready to use.

