Quote:
Originally Posted by Arcanine
Having worked in the Automotive Industry for the last 11 years, and having sold parts for the last 3 years, I feel I can step in.
You're right, heating it will create bubbles, but UltraGrey, UltraBlack, and the more modern RTV's set up with in an hour of being applied, and cure fully with in 24 hours. It can be placed in to service with in an hour.
Also, we're talking about a hot engine block, not a paper & wax flyback transformer in a vintage television. The flyback doesn't get nearly as hot as an engine. It's heat did nothing to aid in making bubbles, or curing it any faster then it would cure anyway.
I requested he used UltraGrey because of that reason, and because I have had amazing personal success sealing up leaky Flybacks with it before. I keep a small tube in my toolbox. Sony Fly's are notorious for splitting in the center of their hard plastic "tire" and leaking out high voltage and arcing. I just slather a little UltraGrey on, let it cure, and the voltage leaks are gone.
Just my two cents. You are 100% right, it will have that issue on a smoking hot engine, but a warm flyback won't effect it in the same manner.
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And I've used RTV many times for corona prevention before - but conductive tracking does occur, and
only at high voltages - where the RTV was heat cured and paths for corona were created.
I've serviced TVs since the 70s, dealt with corona and arcing in 55KV AWG-9 radar transmitter power supplies, 16KV Conrac monitor power supplies, and solved many problems with RTV. But in my humble 30+ years in electronics, I've seen RTV'd flys fail just as often as the originals, and mostly due to the carbon tracks - their death certainly created by heat or disturbed curing. RTV has such a strong dielectric strength that 1/20" will seal against corona in a 50KV system, but one tiny (electron wide) hole is all it takes to fail. Patience and curing at room temperatures, with no disturbance for the allotted time is all that is needed for success.
Now with ATS (Activation Temperature Sensitive) silicone (similar to RTV) products, the crap won't cure without heat, and at a prescribed temperature. I've use it as well - aerospace stuff - we can't afford it - but take some good old RTV3145, the good grey stuff, simply apply and let it cure, no heat. No reason to bake out bubbles that leave a tunnel behind as they head for the surface, setting up a corona/burn path....
Remember, we're trying to save flybacks, not guarantee a kill....
But i digress, it's not my flyback.