What am I doing wrong here?

[Adrian281794878c9q]

I've created all my lines using a drawing tablet and brush tool. All the lines have been closed. I select all > expand appearance and then select all > merge. This is where it goes south. I created a background color and then I send it to back:

Next I select all to isolate:

It's solated:

Now I select the border so that I can delete everything outside the lines:

Now this is what I get:

I've checked all points to see if there are any openings and they are all closed. What am I doing wrong here...

[Monika Gause · Accepted solution]

The *one* thing you are doing wrong is not using Live Paint when it's absolutely appropriate. I know that they are teaching this technique in thousands of tutorials, but it's still a completely inefficient workflow.

So the workflow for this would be: draw your linework, then either make a copy of  the lines layer and then lock the layer with the brushes or expand all the brushes and then use Live paint. Here's how it works: https://helpx.adobe.com/illustrator/using/live-paint-groups.html

[Adrian281794878c9q]

I did eventually find my way to the live paint route which accomplished the end result I was looking for. However I will save this link for future reference as I'm sure it'll come in handy. Thanks