Silicone question for the DIY`ers

Pics, I am not sure what exactly you are describing. And no silcone does not layer, it only causes problems, you will strip and retry. only option.

 

You lost me with starboard. Pictures please

 

Personally I would of totally sealed the tank, and then just laid the starboard in. If you wanted the starboard sealed under it, you could of run another layer underneath it.

Fill it up with fresh water & see what happens. Worse it can do is leak

 

The way I read the OP, the tank was first re-sealed completely. Then, a piece of starboard (cutting board like material) was cut to fit and placed inside on the bottom. Then a bead of black silicone was laid around the edge, perhaps to hold it in place or keep detritus out from underneath. You're wondering if you can put another bead of silicone over the top. I think it would be fine for purely cosmetic reasons. Once silicone cures, not much will stick to it well, not even new silicone. On the other hand, I don't think silicone bonds strongly to the starboard either, so you are already dealing with a similar challenge. I don't think that it will hurt to put another layer of silicone on. Worst case, the silicone may peel back from the starboard or where it overlaps the bead you tried to cover up.

Pics would be great!

 

That photo cracked me up big time. I had to read it three times before i even understood "pichers"

 

I honestly have no idea what the attempt is. I second the picture. hilarious as well.