Hi, Omron do a three probe resistance type float switch which might work for you.
https://www.google.com/search?q=omron+level+sensor&rlz=1C1CHBD_en-GBGB817GB817&oq=omron+level+&aqs=chrome.2.0j69i57j0l4.7766j0j7&sourceid=chrome&ie=UTF-8
Bri
Hi, Maxitrack use mostly TIG welded boilers for their Kit engines. Some or our club members have them. They are very nicely made.
I will have a look at Keith's page as I am a subscriber.
Bri
It looks like they use de oxidised filler rods, helium ( which holds the heat better?) and lots of power. My friend welded me a test piece and it seemed ok. I have yet to have a pressure vessel made to test.
Our club boiler inspector is a very cautious chap and likes the silver soldered method...
Hello Brian. Did you get anywhere with the copper welding information? I am also looking to getting a boiler replaced and would like to have it welded construction.
Bri