Is it okay to use silicone to seal gas furnace heater supply ducts? If so, do you know how long the silicone will need to cure before the system is useable?
Some background:
I've been trawling around my basement recently and found that a lot of my duct connections have exceeded my wildest dreams of what poor craftsmanship looks like. Lots of connections were "sealed" using literal duct tape – which has since crusted off and is not holding on to anything. The joints where circular ducts attach to box ducts are the worst offenders.
Thanks for your time.
Best Answer
Silicone or the Duct Sealant are fine. But, either need to be protected, faced, supported & sealed with Aluminum Foil Tape, the real duct tape. Before anything though, you need to solidify your duct joints (supplies & returns), they can't slip apart or slide & deflect in any direction. Just sink short self-tapping duct screws (sharp pointed ones, not the drill-head ones) through the joint's 2-pieces to lock everything together.