_Gallons_ _Inches_ 40 23-1/2 20 11-3/4 Do not use a metal paddle because of the danger of striking a spark from the drum. Never use galvanized containers for mixing and storing thickened fuels. These may cause the fuel to break down and become excessively thin. An improvised funnel may be helpful in filling drums with prepared fuel for aging or transporting. _d. Temperatures._ (1) _Below 50 degrees._ If the temperature is below 50 degrees Fahrenheit, it is helpful to prepare thickened fuel indoors, in a heated room. All precautions should be particularly observed. (Par 40) (2) _Above 90 degrees._ When the fuel is hotter than 90 degrees Fahrenheit, the thickener reacts very rapidly. In this case, it is easier to prepare batches of 20 gallons each, but any number of batches may be prepared in succession. _e. Moisture._ (1) _Effect of moisture._ Water in thickened fuel breaks down or reduces the viscosity of the gel and thereby reduces the range of the flame thrower. This effect may not be noticeable at once, but the stability of the fuel is affected. (2) _Dryness of thickener._ Dry thickener is extremely hygroscopic, that is, it absorbs moisture from the atmosphere very rapidly. For this reason, thickener is shipped in hermetically sealed tin cans containing the exact quantity of powder required for mixing with 20 gallons of fuel to prepare a 4.2 percent mixture. It is important that the gasoline or fuel oil and gasoline be measured out before the thickener container is opened. The powder then should be poured immediately into the liquid. (3) _Dryness of containers._ It is important that all containers used in mixing and handling the fuel be dry. (4) _Keeping water out of gasoline._ Gasoline, especially when it has been stored in vented containers, frequently includes free water. Therefore, when using gasoline from a bulk-storage tank or an open drum, first place it in a clean, dry drum; allow it to stand quietly for at least an hour; then carefully pour off the gasoline from the top and discard the last gallon or two. _f. Pouring and stirring._ (Fig 25) The liquid fuel is poured into the open drum; a pail or a paddle (Par 35 _c_) is used for measuring. One man then stirs the fuel vigorously. Another takes a can of thickener, splits it with a machete, bayonet, or ax, and pours it immediately into the fuel. Any large lumps of powder are broken by hand before the powder is added to the fuel. When mixing 40 gallons at a time, the two cans of thickener should be opened and added to the fuel in rapid succession. If the contents of the first can are permitted to gel before adding the second can, it will be difficult to obtain a uniform mix. Continue to stir. [Illustration: Fig 25. Measuring fuel ingredient into mixing drum. Paddle for measuring and stirring is improvised.] [Illustration: Fig 26. Transferring newly mixed thickened fuel from mixing drum to storage or shipping container for aging.]