@JRTJH - thank you. That's very helpful. I thought it probably wasn't silicone, but one never knows, especially after one RV dealer I visited a few days ago to try to buy some non self-leveling lap sealant acted like there was no such thing, tried to sell me silicone, and said (after I said, "isn't that the stuff I was told to never, ever, ever use on my RV?") that they use it on RVs all the time
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