Is it correct to say "I ripped the cardboard apart by its side" in this specific situation?

Question

When you tear or rip a thin paper, you just rip it easily "by its surface" (I am not sure I am saying correctly).

Now, you have a very thick cardboard, and it is not easy to rip the cardboard "by its surface" like you often do to a thin paper.

But a cardboard is made by sticking many layers together, and you can put your fingers in the between layers of the cardboard and rib it apart as shown in the above picture.

Is it correct to say "I ripped the cardboard apart by its side" in this specific situation?

Answer 1

You included the answer in your question.

I pulled (or ripped) the layers of the cardboard apart [from each other].

It is concise and I will know exactly what you mean.

Answer 2

Neither "by its surface" or "by its side" mean what you show in the pictures.

There are special words for the parts of cardboard, but they are not in general use.

So most people would just say "rip up the cardboard" and allow the context to describe the actual process.

You could say something like:

You can't tear it in half, but you can rip the paper off it.

The technical words for use by cardboard manufacturers are "liners" and "(corrugated) fluting" So "tear the liner off the fluting" is also correct.

Answer 3

You can "tear a sheet of paper / a piece of cardboard (in half)" or "tear it down the middle (lengthwise)." The words in parentheses are optional. There aren't very many different ways to tear cardboard, so it's not usually necessary to add more detail. You can also "tear off a piece" of something (paper or cardboard).