I imagine that I will want to measure differential vacuum pressure across the char bed and other parts of the gasifier. I want to be able to look at one gauge and have it give me the information I want without having to do any math. And I want to be able to use inexpensive vacuum gauges.
So I felt the need to be able to plumb a second vacuum line to the back of a gauge. It turns out that it’s not very difficult. I went to HF and bought the cheapest pressure gauge they had, thinking I was going to ruin it.
The ring that holds plastic window in place wouldn’t come off. I had to cut it with a triangular file. After I got the ring off I was able to solder it back together and reuse it. It was fairly easy to drill a small hole in the back and solder on a little piece of brass tubing that would allow a vacuum tube to be connected. I used 62% tin solder. The biggest challenge was getting the parts hot enough so the solder would stick. A regular soldering iron wouldn’t do it. I had to heat up a nail with a torch. After I got the soldering work done it was easy to seal up all the leaks in the case with RTV silicone and put the gauge back together. I didn’t even ruin the gauge. I’m counting this as one of my successes. Now I just need to find some cheap vacuum gauges.
Rindert
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