Replies

1. 
   nonexxx | Oct 03, 2003 11:18pm | #1

   Right, it won't burn and  - you will get charcoal...

2. 
   jazzdogg | Oct 03, 2003 11:26pm | #2

   Adam,

   Even if the wood didn't combust, at those temperatures the lignin would be cooked to the point where the wood would no longer have much integrity.

   Sounds like a fascinating scheme - let us know where you go from here, and how it turns out!

   Good luck,
   Paul

3. 
   Steinmetz | Oct 04, 2003 06:09am | #3

   Adam, don't give up your day job. Stein.

4. 
   jackiechan | Oct 04, 2003 06:56am | #4

   Adam,

   There are three types of low melting point glass' that come in the form of non-crystal, compounding, and crystal glass paste.  They are used in the biomedical and technical industries for such things as sealing plasma display panels and specialized layers in certain materials.  The minimum melting point of these materials is just over 600 degrees Fahrenheit - somewhat better than your 800 degree Fahrenheit scenario, but still hot enough to compromise the integrity of the wood. 

   The best bet would be to preform the glass in sections on a non-wood mold.  There are specialty glass adhesives that would allow you to encapsulate the wood by gluing the sections together around it.  This will leave a visible glass seam.  The seams can be minimized by using the fewest number of sections possible, or by using a darker glass, thus camouflaging the seams.  (Or, the seams could be used as a design element.)

   Dan Kornfeld, Owner/President - Odyssey Wood Design, Inc.

5. 
   Tao | Oct 04, 2003 06:10pm | #5

   In Germany, at the end of WWII there was an extreme shortage of petroleum.  Some people ended up using "wood stills" to vaporize the volatile components of wood, and used those vapors as fuel to power automobiles and trucks.  It was smelly and dirty and bulky, but my German friends who were there at the time tell me it worked.

   Get wood hot enough and all the volatiles will be driven off and you will essentially end up with charcoal.  The reason wood starts to combust at 450F or so is, that is the temperature where the volatiles start vaporizing enough to sustain a flame.

   Just a thought: Pyrex and other ftypes of glass witha low coefficient of expansion can be heated enough to melt in one spot while the rest of the glass is relatively cool.  Back in the dark ages in chemistry class we used to form our own glass for pipettes & such.  You could heat the middle of a section of tubing and blow a bubble, or draw it out to a very fine tube without the glass cracking.  Maybe you could form your vessel, stick the wood in, and just seal the end?

   Thought no. 2:  For what it's worth, I have seen glass blowers use wet wooden implements to shape vessels they are blowing -- while the glass was still molten, obviously.  Maybe if you can work REAL fast, wetting the wood might help.  On the other hand, bad timing might make your vessel blow up from the steam......

   Michael R.

6. 
   JohnWW | Oct 04, 2003 06:34pm | #6

   Why do you want to encase a piece of wood in a seamless glass container?

   John W.

7. 
   robkelly1 | Oct 05, 2003 02:33am | #7

   Heating wood in the absence of oxygen breaks it down into smaller molecules and drives off those components which can be gasified. Put "destructive distillation of wood" into Google for more info.

1. 
   Biscardi | Oct 06, 2003 02:03am | #8

   When glass heats and then cools, areas of differential stress end up in the glass. This make it apt to breaking easily. It is therefore necessary to reheat the glass and then cool it slowly in an annealing oven.

   Something to consider.

   Frank

8. 
   johnkollar | Oct 06, 2003 02:58am | #9

       I worked on a a satellite that was just launched, and heat in a vacuum is a big deal for us.  There would be no convective heating because there is no air (Heat like in your oven).  The glass would still radiate energy and still heat the wood (Hot sun on your face).  As long as the glass is not in direct contact with the wood and the glass temperature is low, you should have no problem.

       But, since glass is melts above 1000 Celsius and is workable just below 1000 Celsius, I would say you chances aren't so great.  Even without the oxygen, the wood would char like the filament in a lightbulb.  The filaments glow, they don't burn, because of the vacuume in the lightbulb.  Then again I don't blow glass, so there is most likely an easier way.  I liked the idea about creating a form out of something other than wood.   Use the form, then after the glass cools, slip in the wood and close her up.

   -John