Can't convert from mesh to solid body via faceted

[bryonthompson]

I've tried converting it via prismatic, but it generates too many faces.

[laughingcreek]

directly converting a mesh to a brep almost always results in un-satisfying results.  there are other workflows that can be employed to achieve a result.  the method you chose will depend on what you want to do with this model.  So what do you want to do with this model?  (visuals/pics are a good way to communicate intent)

[hamid.sh.]

This is a badly converted mesh. It is easier to design from scratch than convert the mesh you have. I mean look at this...

But luckily for you I found the predecessor STL from this page which is cleaner and I was able to convert it to BRep with some additional steps.

Actually the original design is bad, having non-manifold geometry (and I guess it was this that led to incomplete BRep conversion you see in my timeline, I mean the yellow warning).

The STL file differs slightly from your file. I added vent holes, you should compare with the file you have and edit wherever you need.