# Help reducing pipe size

**URL:** <https://discourse.shapr3d.com/t/help-reducing-pipe-size/28470>\
**Category:** Modeling Questions\
**Created:** [October 18, 2023, 4:17pm UTC](https://discourse.shapr3d.com/t/help-reducing-pipe-size/28470 "2023-10-18T16:17:21Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![johnb](https://avatars.discourse-cdn.com/v4/letter/j/4491bb/32.png) [@johnb](https://discourse.shapr3d.com/u/johnb)\
**Post date:** [October 18, 2023, 4:17pm UTC](https://discourse.shapr3d.com/t/help-reducing-pipe-size/28470/1 "2023-10-18T16:17:21Z")

</div>

Hi All!

I am trying to create exhaust fan mount that will go from 120mm fan down to a 3 inch exhaust pipe. I have created and extruded 2 pipes, one from the 120mm fan and then one that is the 3 inch pipe. How to I join these together so that a reduction funnel is created?

 ![exhaust fan help](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/9/1/91c0a25a330f1dfdaa3f7188eb0fbd12952470b6.png)

---

<div class="post-metadata">

**Author:** ![TheBum](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@TheBum](https://discourse.shapr3d.com/u/TheBum)\
**Post date:** [October 18, 2023, 5:05pm UTC](https://discourse.shapr3d.com/t/help-reducing-pipe-size/28470/2 "2023-10-18T17:05:24Z")

</div>

The Loft function will do what you want. Create separate sketches with the two pipe outer diameters (suggest using using construction planes offset 0mm from the ends of the pipes and projecting the pipes onto them), remove the inner circle of the projected profiles, loft the two remaining circles, and then use the Shell operation to hollow out the body that was created.

---

<div class="post-metadata">

**Author:** ![TheBum](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@TheBum](https://discourse.shapr3d.com/u/TheBum)\
**Post date:** [October 18, 2023, 5:38pm UTC](https://discourse.shapr3d.com/t/help-reducing-pipe-size/28470/3 "2023-10-18T17:38:38Z")

</div>

[![](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/2/d/2db6b85ecf156e97ed0c3b4b5463d0bd2d4d4c0c.jpeg "Screen Recording 2023 10 18 at 12 31 03 PM") ](https://www.youtube.com/watch?v=Un8c1kPDc5g)

The main issue I encountered was the inability to make a multiple profile selection for each of the loft surfaces, so I had to remove the inner circle to allow me to use everything inside the outer circle for the loft operation. Also, for some reason, I had to delete the inner circle three times.

---

<div class="post-metadata">

**Author:** ![johnb](https://avatars.discourse-cdn.com/v4/letter/j/4491bb/32.png) [@johnb](https://discourse.shapr3d.com/u/johnb)\
**Post date:** [October 19, 2023, 7:01pm UTC](https://discourse.shapr3d.com/t/help-reducing-pipe-size/28470/4 "2023-10-19T19:01:58Z")

</div>

Howdy!

Thanks so much for the tip. This worked on iOS, but would not work for me on Windows 11. For some reason, the Win 11 client would resize the new body instead of creating a shell.

Part is ready to print!

Have a great weekend!