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Author: Subject: DIY distillation app
International Hazard

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[*] posted on 14-12-2014 at 22:03

Quote: Originally posted by Hennig Brand  
Well, I think learning the simple skill of making Teflon bushings, allowing the hobbyist to make their own safe and reliable distillation and other equipment while eliminating or significantly reducing the need for glassblowing, is very worthwhile. (quote trimmed for space)

[Edited on 12-12-2014 by Hennig Brand]

Hennig could you type something up or show some examples of the teflon bushings/glass-teflon connection you have made? I think a lot of us could really benefit from it.

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Hennig Brand
International Hazard

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[*] posted on 18-12-2014 at 13:45

No problem, I posted the following in the "nitric acid synthesis thread". There are also a couple of pictures of the Teflon bushing made (the bushing could have been made much more neatly if more time was taken and more attention was paid to detail). Once one has Teflon round stock of an appropriate size, and access to a lathe or someone who has a lathe and doesn't mind taking on small jobs, it is very simple. Here is a link to where the following quote was originally posted:

Quote: Originally posted by Hennig Brand  
Here is a very simple little glass still I made a year or so ago from common flasks without ground glass joints. The most important part of the apparatus is the Teflon bushing, which can be easily made on a lathe from Teflon round stock of an appropriate diameter. Two approximately eight dollar flasks were used and a piece of glass tubing obtained for free. A piece of Teflon round stock was purchased for $30 which provided enough material for 4 bushings. The center hole of the bushing was bored out slightly oversized and the outside diameter of the section which would slide into the flask was made slightly undersized. This allowed the glass tubing and outer diameter of the bushing to have many wraps of Teflon tape applied so as to give some of the elasticity that would normally be present if a rubber stopper was used and provide a better seal. Experiments showed that the bushing still tended to rise slightly, once the flask got hot, allowing vapor to escape. This was easily solved by applying a few wraps of black electricians tape, to the top of the flask and bushing, which completely solved the problem. The first picture of the apparatus in use is from early spring when temperatures where near freezing and with slow distillation air cooling was adequate. The second picture is from a hot day this summer and the receiving flask was placed in an ice bath. I have ideas for how one of those little $10-12 centrifugal table top fountain pumps could be used to pump the water, or iced water up, over the round bottom flask receiver if extra condensing power was needed.

A steel file may be needed to score the tubing if it needs to be made shorter. A propane torch is needed to heat the tubing so that it can be bent and then annealed.

BTW, I do have a ground glass distillation apparatus, but just for fun and skill development I wanted to build this one.

I probably should have another stopper, a two hole, in the round bottom receiving flask. A smaller diameter piece of glass tubing could extent out of it increasing the cold surface area and acting as an air cooled reflux condenser. This would help reduce the amount of escaping nitric acid vapor as well as probably reduce the amount of absorption of moisture by the nitric acid.

[Edited on 30-6-2014 by Hennig Brand]

The rest of the discussion was continued in this thread.

[Edited on 18-12-2014 by Hennig Brand]

"A risk-free world is a very dull world, one from which we are apt to learn little of consequence." -Geerat Vermeij
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