Large-Scale Methamphetamine Manufacture

7.0 Laboratory Equipment and Procedures

Unless one has spent many hours doing organic syntheses, there are many lab techniques and procedures that that will be unknown. This section attempts to cover some of the basics applicable to clandestine labs.

7.1 Fume Hood

One must have a fume cabinet, period. Fortunately, they are easy to build. This writer constructed an integrated fume cabinet/lab that fits on a single sheet of plywood. Note the plastic sheeting used to seal the enclosure when noxious fumes are present. Not shown is the exhaust fan that runs continuously. Use a fan that moves at least 250 cfm of air.

7.2 Water Aspirator

A high volume aspirator is required for many of the procedures described in this document. Although industrial strength aspirators can be purchased, they can also be constructed from common pipe fittings found at the hardware store. Shown in the accompanying photograph is this writer's aspirator. There is a lot of cut-and-try involved in building a homebrew aspirator, so purchase one if possible. Also required to complete an aspirator system are a pump supplying 50-70 psi of water pressure and a reservoir of cold water. The pump can be a common 1/3 HP jet pump wired to a switch in the lab. These pumps are inexpensive, but are only good for about 200 hours of hard use, so keep a spare handy. The water reservoir must hold sufficient volume to prevent rapid heating of the water and be able to absorb solvents and fumes. A good reservoir size is about 100 gallons or two fifty-gallon drums connected together at the bottom and filled to 2/3. Water temperature is very important. The colder, the better. In sub-freezing temperatures, just add some plumbing antifreeze and one's aspirator will pull a mighty vacuum. Unfortunately, as the water temperature rises, so does it's vapor pressure, and this imposes a limit on the vacuum one can pull. To reduce the vapor pressure of the water, lower the temperature with a block of ice from the freezer.
Another essential component of the system is the vacuum trap. The trap keeps one's mistakes during distillation from ruining the rest of the equipment. Placed between the aspirator and the vacuum hose, it collects any liquids not condensed into the receiver. One can be made using a 1-qt. Mason jar. Using a drill press, carefully drill two holes in the top that are just big enough to accept the base of a 3/8" brass nipple. Braze the nipples to the top. Using a gasket, seat the top on the jar. Screw the top down firmly and attach the vacuum lines (Use 3/8" reinforced hydraulic hose, as this size fits the nipples on vacuum-takeoff glassware and doesn't collapse under a good vacuum). Place the vacuum trap somewhere it won't get bumped; this writer built a 3-sided wood box lined with insulation. This is because the Mason jar will easily implode under a good vacuum. Check for leaks and use some pliable external house caulking to fix it. It is a good idea to change the water in the aspirator system daily, as solvents will attack the plastic pump impellors.
The next requirement is for a vacuum distribution system. The accompanying picture shows the vacuum input from the right, a distribution hose on top that attaches to glassware at the other end, a 0-29" Hg vacuum gauge, and an industrial strength 1/8" bleeder valve. A more suitable bleeder valve is a needle valve with a 0.050 aperture. The entire assembly is located inside the fume cabinet. The vacuum inlet at the right comes from the vacuum trap and may be replaced as required with a vacuum pump hose.