Re: Silicone + tree fern fiber
Loose tree fern pressed into a thick coat of silicone, is one of my favorite build tools. I assume you mean GE silicone 1? I've used a lot of that in many builds. I've planted a lot of exotic plants in GE 1 and not had any problems. I am aware of the problems with GE 2 and have spoken about that more than a little, in the past.
It's hard to get perfect coverage with clear silicone. It's difficult to find GE 1 in colors. Plus, as a retired window glazier, I've used hundreds (at the least) of tubes of silicone. Some are a pleasure to work with. Others are thicker and I don't care for that. I like it easy to work with, in addition to having the proper curing agent. The curing agent is what differentiates GE 1 from GE 2.
Anyway, my favorite silicone is C. R. Laurence 33s. I've often called it the Cadillac of silicones. You may have to go online to find it. It's available in many colors. My favorite color for a substrate background, is Bronze. You will find it is actually brown, but as it is specifically made for the window industry, they use glass industry color names. Brown blends in beautifully and hides bare spots. Black would be my second choice.
Doug aka Pumilo
The second "i" is silent. It's so silent it's not even there!