What to use?

I don't what to make LR, but what to make some things that will not effect my tank, what is the best to use, porcelain, clay, cement, or any other suggestions. I must be able to mold it.

 

Milk crate and a blow... paint stripper.

 

Maybe i got it wrong ; but i get the picture that Sean is wanting to create some type of structure for his reef, with a reef safe material

 

Nope not polyurethane. Normal plastic milkcrate that can be cut and melted with a heat gun to create a reef rack.

 

Do you mean egg crate? Will coral grow on it? I know coralline does.

 

No... think of a case of castle quarts. Milk cartons come packed in similar cases