Just a couple of comments - Henkel, who make it, claim Super Steel is metal-loaded. So whatever you do don't let it run down inside the valve base and touch the valve wires or pins. Serious Glue is rated, again according to the manufacturer
https://diy.evo-stik.co.uk/sites/diy...rious-glue.pdf, as good for temperatures up to 130C. Hard-working power valves can get hotter than that though.
Cheers,
GJ