Can't save Fusion comps (Fusion in Resolve)

Note: I'm using Fusion inside Davinci Resolve Studio.

I've made a Fusion composition by initially selecting two clips on the timeline of the Edit page and using the New Fusion Clip command. Everything's worked fine and I'm back in the edit page.

Say I want to now save that Fusion comp to a bin, I drag it to the bin and there's my comp. Only when I drag that comp into another timeline the VFX have gone, open the comp in fusion and there's only media in and out. The only way it seems to get a Fusion comp to another timeline is to copy and paste from one timeline to another. Is that right?

Seems like you should be able to have a bin full of Fusion comps.

Correct. Fusion Clip compositions are not preserved by copying the Clip to a bin.

The only composition types that get preserved by copying to a bin are Fusion Composition and Adjustment Clip compositions. Not other types.

You'll have to back-up the composition manually, using one of these methods:
- File -> Export -> Fusion Composition -> save it as a .comp file, then later File -> Import -> Fusion Composition to restore it.
- Select all the nodes, copy, paste it into a text file and save it on disk, then to restore just copy all the text and paste it into a new comp, which will re-create all the nodes.
- Copy and paste the clip between timelines, as you have been doing.

For more details on the different types of Fusion composition in Resolve and their various differences, I wrote a post to describe them here: Resolve Fusion: composition types and how they access media.

This is great information, thank you!