To wrap the construction phase up, the column has to be packed with something for the vapors to condense on as they pass up the tower from the boiler. There are a lot of things you can use to pack the tower. Recommendations range from marbles, glass beads, copper or stainless scrubbing pads, to broken automotive safety glass and others.
Packing is a poor word to use for this material. It implies a dense filler. What we really want inside the column is something that won’t pack, burn, melt, dissolve, or release impurities or poisons into the vapor in the column.
We also want that material to have as large a surface area as possible, and at the same time offer as little resistance as possible to the gas and liquid flows inside the column. It should be easy to clean, and above all, it should not settle or pack down in the column.
And while that is a pretty tall order, there is a product that satisfies all these requirements. The product is called Raschig Rings. They are hollow cylinders made of unglazed ceramic material. They are made in many sizes but the ¼" diameter is perfect for this kind of column . They look like this:
From www.partyman.se Web Site
Finding a good source Raschig ring source is sometimes difficult. A search of the Thomas Register of American Business turns up about 19 suppliers. But for the most part these suppliers are large companies, many of whom specialize in doing business with the big refineries and oil companies. As such, they really do not want to deal with a small laboratory or an individual distiller.
Some of the prices for 6mm Raschig rings can be shocking: one company wants $80.40 USD for a liter quantity (you will need two liters), and requires a $300.00 minimum order.
Another wants $24.90 for a box of 300 rings (there are 85,611 6mm rings in a cubic foot).
Under the circumstances, if you've decided to use this packing you should check out Gert Strand's Partyman website at http://www.partyman.se. He carries them and the prices there are a fraction of the larger companies on the Thomas Register.
If you are located in the US, you can save some postage charges by contacting the Brew Haus at http://www.brewhaus.com. They currently are selling a liter of 6mm Raschig Rings for $15.95 USD.
As a last resort, you might take the time to cut up a few thousand ¼” slices from some ¼” copper or stainless tubing if you have the scrap laying around and a lot of time. But if you have to buy it new even copper tubing costs about $0.40/ft USD, and it's definitely not worth the time to cut it up.
Probably the best alternative to Raschig Ring packing is stainless steel or copper pot scrubbers. You can get them at most local grocery stores. They come highly recommended from several sources, and while you may not get 95% purity, remember that you'll need to dilute the distillate anyway if you intend to drink it. Just be sure you clean them up by boiling them in water before you use them, and don't pack them too tightly in the column.
No matter what packing you choose, fill up the tower to just above the top cooling tube if you've built the Internal Reflux still. Otherwise fill it up to a point just under the reflux return tube on the Valved Reflux column. Put the cover cap on, and attach the cooling hose couplings with stainless hose clamps. You're almost ready to go!
The last two operational issues are heating and cooling. They are covered in the next few pages.