Here are some updates from the research department!
I think the mica washer works great but I am not happy about the fact, that it is not really solid enough for cleaning and therefore disposable.
@Mojo wrote to me a while ago: "Why don't you use a metal washer?" I thought, no way, a metal washer
would also lead the heat to the bottom part of the middle section. After realizing that the mica washer is not really the final answer to this issue, a fine ceramic washer came in to my mind. I am sure it would work with ceramic but after getting some quotes from different companies I had to accept that ceramic is far too costly and not a solution as well. Bummer, I thought.
After this I did some serious brain storming, I had a feeling that there must be a solution out there in the universe somewhere. I wished for a solution, took some herbal brain enhancer and traveled through space and time and guess what? I found what I was wishing for: it is a metal washer with a particular shape!
Here is a drawing of the idea:
The idea is simple but effective, a stainless steel (bad heat conductor) washer with a triangular shape! It was clear to me that a washer like this would lead far less heat than a flat washer. But suddenly I had doubts about it and questions like; where does the most heat come from? From underneath or are the hot gases passing by on the side the main reason for the slow burning of the wood? This question I could not answer by thinking and reflecting, I had to test it. Yesterday afternoon I grabbed a piece of SS and made a washer on my good old lathe.
Here is the test:
Two identical middle sections are needed to test the effect of the SS washer.
One of the middle sections I sanded down.
The two middle sections, one with the SS washer.
The two middle sections, the one on the left with the SS washer.
Now, everything was ready for testing. Will the SS washer protect the middle section from the heat.
For this, I over heated both middle sections intentionally and identically several times. I could tell that I was over heating by the discoloring of the filters, they started to turn a bit brown which is way above the temperature for vaporizing.
Here are the results:
The result is clearly visible, the middle section with the SS washer is far less burned than the one with out the washer. Taking into account that both middle sections were severely over heated, we can assume that in normal use, a middle section with such a washer would be perfectly protected from the heat and last way longer than with out the washer.
This is almost a historic moment for me, this will be the first improvement of vapman in a period of over 10 years! So far, I have not asked for any quotes for making such washers but I am positive that it will be feasible for a reasonable price.
Be good, take care of yourself and keep your filters clean and shiny...
vapman