Hot air guns

Under reduced pressure, the solution sometimes Joams. This can be avoided by heating the top part of the Schlenk tube with a hot air gun. 

A steam bath or hot air gun may be used with care to speed up evaporation of the ammonia. 

The most suitable wires for this purpose are pure lead, indium and gold. The Pb and In wires should be between 0.1 and 0.4 mm thick, the Au ca. 0.05 to 0.1 mm. Under presure, these metals are deformed plastically and adapt themselves to the contour of the joint. There will momentarily be the greatest pressure at the point at which the ends cross over and thus the greatest deformation will occur there until a uniform thickness is attained. If such a joint resists dismantling, it can usually be freed by heating it gently with a brush flame or hot air gun. 

It was noted that in an attempt to synthesize fluorodiiodomethane, when triiodomethane (approximately 1 mL) mixed with an equal volume of 10-year-old mercury(I) fluoride was placed in a glass finger and evacuated, immediately upon heating with a hot-air gun, the mixture detonated.54 Great caution should be exercised with reactions of this type. 

Valve I is opened and the trimethylindium is sublimed, under static vacuum, into the 2-L flask (trap-trap distilled). A hot-air gun is used to assist this sublimation process and to ensure that all the trimethylindium is collected on, or near, the surface of the cold, or frozen, amine/petroleum spirit suspension. When all the trimethylindium is trapped into the 2-L flask, valve D is closed to seal the 2-L flask and the rest of the system is filled with air through valve H (make sure valve D is closed ). The liquid nitrogen Dewar is removed and the 2-L flask is disengaged from the rest of the system by careful disconnection between the adaptor housing valve D and the U tube. The top of this adaptor is plugged with a stopper. 

The 2-L flask is partially filled with argon through valve F and allowed to thaw—a hot-air gun can be used to speed up this process. On equilibration to room temperature the flask is filled fully to atmospheric pressure with argon. On stirring, the suspension dissolves gradually to form a clear colorless solution of the adduct. If the solution is cloudy, it can be filtered into a second flask as described above. 

The product is separated from traces of amine and an unidentified nonvolatile oil by resubliming the trimethylindium, under static vacuum, from one storage bulb to another through a U tube with gentle warming from a hot-air gun. Yield 71 g (97% based on adduct, 89% based on indium trichloride). 

The intensity at small scattering angles is very high, which can lead to count-rate-dependent gain variations and a rapid deterioration of the detector. Copper-beryllium multipliers can be rejuvenated easily by heating them first with a hot air gun to 100 to 120°C and then rinsing the hot multiplier in cold methanol. 

Thin layer chromatographic analysis of 4-acetoxyazetid1n-2-one was carried out on E. Merck Silica gel F254 plates by elution with ethyl acetate. The hexane-soluble impurity (Rf 0.67) was detected by shortwave UV. 4-Acetoxyazetidin-2-one (Rf 0.38) was detected by exposure of the plate for 5 min to chlorine gas followed by spraying with TDM solution (Note 9) and heating with a hot air gun. 

Any exposed bubbles may be gently popped using a soft gas flame or a hot air gun. The heat source must be used to a minimum and kept moving to prevent damage to the surface. 

If the thermometer has no expansion or contraction chamber, heating the bulb should not be attempted because there is no place into which the liquid may expand to remove bubbles. Occasionally it may be possible to heat the upper region of the liquid along the stem (do not use a direct flame use a hot air gun or steam). Observe carefully, and look for the separated portion to break into small balls on the walls of the capillary. These balls may be rejoined to the rest of the liquid by slowly warming the bulb of the thermometer so that the microdroplets... 

To facilitate the creation of a high vacuum, heating the walls of a system will help drive off moisture. On a glass system, this heating is typically done with a hot air gun. It is important that any heat source is not aimed at stopcocks or joints on the system. However, it is often necessary for very large stopcocks or joints to be heated before they can be rotated or separated. Therefore, pay attention and do not heat any more than necessary. These stopcocks or joints require frequent grease replacement. Do not dwell the hot air gun on any particular spot while the system is under any level of vacuum and the hot air gun is on full. It is possible for the glass to get sufficiently hot for air pressure to collapse the wall of the system. To prevent this, simply move the hot air gun as one would move a paint sprayer. 

There are six ways to heat materials in the lab open flame, steam, thermal radiation, electromagnetic bombardment (microwave ovens) passive electrical resistance (such as hot air guns), and direct electrical resistance (such as hot plates). All of these heating methods (except thermal radiation) use conduction to heat the container holding the material to make the material hot. 

Hot air guns are used to provide isolated, directed heat to individual targets. This method may be used to heat an individual sample on a vacuum line or to soften the grease on a stopcock. Although one could use a standard hair dryer, it cannot provide the control or endurance of an industrial-strength hot air gun. 

There are two types of hot air guns those that have a fan and those that do not. The obvious advantage of those with fans is that they are self-contained. The disadvantage is that the fan motor can create sparks, which could be hazardous depending on ambient gas conditions. The disadvantages of the motorless (no fan) design You must have access to pressurized air, and the unit must have both a power cord and air hose for operation. 

Motorized air guns allow extra air to enter the side of unit through an air gate to vary the amount of extra air that can enter the air gun. The less air that can enter the side, the hotter the air exhaust. A hot air gun can produce extensive heat which can easily peel paint or crack a window pane. By concentrating the heat, from a hot air gun on a glass vacuum line, it is possible to have the glass walls be sucked in by atmospheric pressure. 

Any small-sized stopcock that requires heat to turn should be removed, cleaned, and regreased at the first opportunity. Large stopcocks may require a hot air gun for all rotation. Because heat ages stopcock grease faster than normal, the grease should be replaced two to three times more often than the other stopcock grease. 

If you have pressurized air in your lab, you can use a motorless hot air gun. These units are smaller than standard hot air guns and are typically about the size of small home hair dryers. Motoiiess hot air guns only require heating filaments because they do not have fans. To use one, a flexible tube is attached to an air supply and the hot air gun. If your lab does not have plumbed-in compressed air, or the location of your outlet is too far away from where you want to use the hot air gun, another option is to use a compressed gas tank of air. Do not use compressed oxygen or any flammable gas for the air supply. You could use an inert gas, such as nitrogen for your air supply, but it would be costly. 

Probably the most common piece of worn or damaged equipment used in the laboratory is a hot air gun s electrical cord. These cords are frequently frayed due to their heavy use. Electrical cords should always be replaced as soon as there are any signs of fraying, and hot air guns deserve no exception. 

E. Merck silica gel F-254 plates were used, with 2 1 hexanes-ethyl acetate as eluent. Visualization was effected by spraying with a 10 phosphomolybdic acid in ethanol solution followed by heating with a hot air gun. (2S,3S)-3-Propylox1ranemethanol had an of ca. 0.3. 

UV. 4-Acetoxyazetidin-2-one (Rf 0.38) was detected by exposure of the plate for 5 min to chlorine gas followed by spraying with TDM solution (Note 9) and heating with a hot air gun. 

Evacuate the vessel and heat with a hot air gun. Flush with nitrogen. Stir the magnesium turnings under an atmosphere of nitrogen overnight. 

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