Hi all! A bit OT, but I'll ask either way. My new 640 has the black silicone smeared on the grease deflector crack, but the person missed some spots at each end. The silicone on the grease deflector and around the firebox is a shiny black, whereas the Permatex 81878 that the manual recommends is the ultra copper, which if I remember from my last exhaust work(!) is brownish-red.
Is the 81878 still the recommended product or is the black one better, and if so is it the Permatex Ultra Black?

 

It's hard to tell you what exactly is different, but there are fans of both

 

Of all the sealants I've used, Gorilla 102048 was the one that worked best for me. The silicone composition of this sealant allows it to dry quickly on any surface. So the very next day, I could go on a trip without fear of something leaking in my van. That's why waterproof sealants https://outdoorlifecafe.com/best-caulk-for-rv-exterior is what I advise you to use. Don't even think about regular. You'll waste your money on junk. In cases like this, it's better to take care of the quality of the product. After all, you won't have to think about this problem again in the future.