Yes, you could use something for fixing cracks in Franklin stoves, or fireplaces. That you can probably get at ACE Hardware, Home Depot, Lowes, but will likely come in black, black, and black. Or something for automobile engine repair or exhaust. That would be an Autozone, Checkers (now called something else) or Pep Boys. Another possibility is model airplane supplies. They should have some glues for around the engine parts that would be high temp. I wonder if appliance parts stores would have a high temp adhesive for oven, hot water heater, dryer or other parts, like over temp thermoswitches.
To do something more thermal conductive would be to go to a large hardware or auto parts store, look for an epoxy that is rated for higher temps (250F, 125C or higher), then mix in some aluminum or copper filings to help conduct the heat away better.
Another online source would be McMaster-Carr
Mike