Leaking weldless ball valve installed on stainless brew kettle

I recently installed a fermentap weldless ball valve kit and a weldless thermometer on my 10 gallon stainless steel brew kettle. Following the directions, I found both the ball valve and thermometer leaked. After reading some posts on here, I placed the supplied red washer (which I presume is silicone) on the inside and a rubber washer on the outside. The HBT thread did not say to use a rubber washer, but that's all I had here at the house. I have tested it and they no longer leak, but I haven't tried it out during a boil. I'm wondering if the regular rubber washer on the outside will melt. Any thoughts? Should I try to use a silicone washer? Thanks.

 

Horrible bulkhead design there but I do believe you can get it to stop leaking if you wrap the threads with an extra healthy dose of teflon tape.

 

I know this is an old thread but I came across it after I ran into the same problem. At first it leaked about a drip a second for me (manageable but I imagine it could be worse for others). I drilled a 7/8"-1" hole and installed the silicone gasket on the inside of the pot with the washer and nut behind it and tried several tightening amounts but nothing worked.

I replaced the silicone gasket with two 314 silicone o-rings 70A Durometer, 3/4" ID, 1-1/8" OD, 3/16" width (check amazon) on the inside as well as against the bulkhead on the outside of the pot. I tested with a 6-gal boil for 30 mins and no leaks!