Seam sealer

[Resto-Rand]

Ok, I went to the paint and bodywork forum and got 0 responses so far. I did a search and none of the threads answer my question.

So here I am where I hang out with my question.

Does anyone know if 3M 08505 seam sealer will eventually harden up if applied 1/2" thick in some areas?

Thanks so much for any info. I couldn't prime it because I didn't know. And now the cab is covered because we expect rain.