First attempts

These are my first works. The smaller tubes are borosilicate lab tubing and the larger tube is fluorescent light bulb section. My goal is to make custom electron tube experiments.

The afar left tube is sealed. Initially i sealed on end and then annealed the tube. After it cooled it inspected it and supplied a small amount of pressure with a rubber bulb. I then tried to form a bubble using the rubber tube. I found this to be pretty difficult as the bubble would get out of control rather quickly. After working with the tubing i found that expanding air inside the tube had enough force to form a good bubble. This was also a lot easier to control than squeezing the rubber bulb.

After forming a small bubble i added some water. I thought this would be a good way to test myself.
Since most glass work is done using gravity i would be quite a challenge to have water in the bubble.
With the water i could no longer use gravity since the water would rush down into the working glass and likely to crack it.

I was able to seal the end of the tube while the water was in the tube. I then tried to make another bubble but got ahead of myself and almost burst the bubble. It is very difficult to work the bubble being that the glass is stretched very thing. Instead of attempting to repair the bubble(which skilled glass workers can do) I moved closer to the center of the tube to form another bubble.

All in all the first sealed tube turned out quite well as far as i am concerned. 

For my second tube i thought i would again seal the end of a tube and create a bubble in the same end.
The other end of the tube was drawn out so as to create a very small inside diameter. This challenge was two-fold. First to create a small diameter tube and secondly, put a small amount of water inside the tube. This process is very similar the construction of a thermometer. While reading the glass working books i found the method of which they filled the thermometers very notable. To add a liquid to a tube that has similar construction of a thermometer simply place the tube into the liquid and heat the bulb. A portion of the expanding air inside the tube will be forced out of the tube. The tube is then cooled while in the liquid. The cooling process causes the air inside the tube to contract which in turn draws the liquid into the tube.


The last tube in the picture is from the fluorescent light bulb. I broke a few sections while getting a feel for the glass. I have found that it is much easier to work the glass if it is very slowly brought up to working temperature. Pretty much the annealing process in reverse. Then after the tube is upto or near working temperature it is annealed.

Once cooled this glass tube can be brought up to working temperature at a respectful rate. In order to seal the end of the tube i discovered the end of a 12oz soda can to be a very good tool. The concaved structure allows the tube to roll over into a dome which occurs very quickly. Initially i tinkered with gravity to seal the end. This works but seems to take a great deal of time.