Hi Gord, I've attached a fixed up version here that is now a solid and should boolean ok.

There were some other problematic areas of the model, the entire bottom wasn't all aligned to be on the same plane and there was a kind of awkwardly squashed corner spot in one area.

To make this fixed up version and have it be smoother, I set it up like this and selected these 2 edges:



And then used Construct > Blend to put in a smooth blend surface:



- Michael

Hi Gordon, here's a different method that makes fewer surfaces. For this one I started with lines put in for the straight areas:



Then put in these curve blends:



Then I used the rebuild command to make these curves made up of one single segment and then used Construct > Loft to make the surface:



Then I used Edit > Trim to divide the edges, then Construct > Sweep of the bottom profile up along those edges to make this piece:



Then select these edges:



And use Construct > Blend to put in a blend surface there:




The part that's difficult about modeling things in a "patch by patch" manner like this is that you need to use Blend or Fillet in some areas to fill in a smooth surface for you rather than trying to construct every single surface directly.

- Michael

Brilliant, thanks. Not used the blend command before.

Gordon