Problem with Boolean function

zhen_yang_chew301

I am very new to Onshape, so very unfamiliar with the boolean function. I am working on a project for a pipe structure, and the criteria is to only work on surfaces. I am trying to merge the two pipe surfaces, but Onshape followed with the prompt " Boolean resulted in no geometry change. The parts either do not intersect or are totally contained." Would be very helpful if anyone knows how it is done, or could explain why this is a problem?  

Pipe Project
https://cad.onshape.com/documents/eb9e5e7ab95e3c9cbb2f05d7/w/a8cb5905d1595fc5a0c53080/e/d8a6db664cdd3fbcea92365c?renderMode=0&uiState=62d899cf6b3ece5008aff81f

NeilCooke

Change Extrude 1 to "Up to next" and "Add"

zhen_yang_chew301

NeilCooke said:

Change Extrude 1 to "Up to next" and "Add"

@NeilCooke Ive tried this. But is there a way to boolean it after all that changes i have made. I believe if i boolean the two parts before delete face, it will create a hole between my part 1 and part 2 pipe. Im trying to attach the secondary pipe to the main pipe without creating a hole between them. 

NeilCooke

Not quite sure what you are trying to do, but please take a look at this:

https://cad.onshape.com/documents/80fe991ecb92617e9f4f3d87/w/de38e855f544a64283b46bc4/e/12c82ea93308642e622c7e5e