Mark: thanks a lot for your advice. what happened was that i was reading posts where it was mentioned just as RTV, and didnt think that it had to be 1 specific.
i choose the 1 i used because said that it dries fast, but also saw more than 1 black.
but now is too late, and i hope it also does the job. will see.
and, if it fails soon, will use the 1 you advice.
thanks again.