>>I got it unioned but now the surfaces are broken and I can look inside ...<<
I dont quite understand.
Are you saying you have attempted to boolean union the "Triangle" to the other main part, and that then tears/breaks the model? If yes, then remove all the faces that are touching for the union, then use join. (if you have a fairly complex shape (such as the triangle) then attempting to union, the coincident faces causes problems).
Repost the model if I have not understood the problem.
 Steve
