High temp sealant/retort cement recommendations?

delcrossv

Any product recommendations for high temp sealant/ retort cement for resealing a dry firebox to a cast iron heat exchanger and resealing the exchanger to the draft hood?

Something that can be applied outside the joints as the boiler won't be coming apart to put the sealant under the flanges.

EBEBRATT-Ed

The hx to draft hood could probably use RTV silicone. Home Depot sells some high temp stuff, it's not with the regular caulking its with the stoves & fireplaces. Took me a while to find it.

There's always furnace cement which I don't care for it dries out and cracks

EdTheHeaterMan

RTV sillycone is good up to 450° If you are sealing an oil furnace vent that may not be a high enough rating. I have had good success with High Temperature Stove gasket cement. its black and it comes in a caulk gun tube. Rated to 2000°F

https://www.amazon.com/Rutland-Stove-Gasket-Cement-Cartridge/dp/B000V4LTXC/ref=asc_df_B000V4LTXC/?tag=hyprod-20&linkCode=df0&hvadid=167125490367&hvpos=&hvnetw=g&hvrand=10710174357717121358&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9010489&hvtargid=pla-307179214708&psc=1