Newbie question - can you shorten these effectively?

[Alan Ambrose]

Was going to use these to connect my MVHR box to the ducting (either 180mm foam ducts for external or the 180mm connectors on the plenums):

 

Ubbink Aerfoam Insulated Mass Flow Ductwork Sound Attenuator 180mm

These are nominal 1m and stretchy of course. The best connections I can see would bend to about 0.5m long - can I shorten them OK by cutting and forming something a bit like the factory ends?

[MikeGrahamT21]

How about just getting a shorter one? https://bpcventilation.com/collections/ductwork-silencers/products/quiet-vent-semi-flexible-silencer-range

[Alan Ambrose]

Oh yeah  I was only looking at Ubbink ones duh, I see DEC has a range e.g.

 

Flexible silencer non-woven with connection diameter: 180 mm length 500mm 72620518 | Ventilationland

 

Actually, maybe DEC is actually supplying Ubbink anyway as they look so similar.

 

Edited 1 hour ago by Alan Ambrose

[Alan Ambrose]

A related question - has anyone here used (or felt the need for) some kind of sound absorbing feet or mounts in addition to whatever is on the bottom of the boxes?

[MikeGrahamT21]

Mines wall mounted, and yeah some sort of sound absorbing is a wise move, maybe not to start with, but as the unit ages and the fans inevitably get slightly unbalanced, it will help to stop any vibrations making their way out and about.

[Alan Ambrose]

Ah thanks Mike.

 

For anyone following along in future, this is what Gemini thinks, but having looked more closely at Ubbink's offering, I don't see any reason why it can't be shortened - it looks just like a bit of flexible insulated pipe that has some ends formed in it - and I think you could do that forming by hand without a problem.

 

[Alan Ambrose]

This is what it thinks about the mounting issue and that sounds good to me: