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Can HVAC ductwork be shrink wrapped? Like with flame retardant construction film? Maybe something like this.

I have substantial leaks coming from where the ductwork connects to the air handler. A technician tried to tape it up and then tried to slather a thick layer of duct butter... and then tried even more duct butter. There continue to be lots of little holds leaking out. Condensation seems to be melting the butter away. Because of the location, removing/replacing would require moving the entire furnace/air handler. I would like to find another way to seal it up. It seems the easiest way would be to shrink wrap it to seal it all up.

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What you linked to may be the simplest solution for now since the HVAC guy goobered up the duct work with mastic.

Otherwise the tape that J Hirsch linked to at HD would be the fix for it, and it still may if the mastic that was used will allow it to hold, if the duct is NOT flex duct, so there is backing where the tape is applied. If it is flex duct and there is backing, like where the duct attaches to the collar at the unit, then it will work...possibly. Again the mastic may keep it from bonding well. If the duct is clean, free from dust, that stuff will stick really well.

Using the heat shrink stuff may come at a great cost unless you go to a marina where they use the stuff regularly for winterization for the upper deck of the boats in the storage yard. But that may be really wide stuff, but a 3 ft wide strip could be cut off the end and it may get you a 12 X 3ft piece for example.

Explain what you need it for and you may be surprised, the folks may even give you tips on how to work with it. Whenever I use something that is not the norm for a particular item, the folks that have it, once they understand what I am needed to accomplish are usually more than willing to help. Then..... sometimes...

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  • Thanks @jack I appreciate you sharing your expertise. The area is fairly wide, about a foot wide or more where I can feel air coming out of the mastic. You are right, applying tape doesn't work well because it is not smooth. It is not flex duct where the issue is. I just contacted Pro-tect which has the shrink film linked above.They said it should be just fine under 225 degrees.
    – For the Name
    Commented Apr 10, 2020 at 15:31
  • It looks like you will have a lot left over.....
    – Jack
    Commented Apr 10, 2020 at 16:01
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What is used is silver aluminum tape. "Duct Tape". It's the standard in sealing, unless you want to use the duct sealant (mastic/polymer), although that's frankly more of a PITA than tape.

Edit: Silver Aluminum foil tape, not 'plastic cloth grey tape'. Here's an example

https://www.homedepot.com/p/Nashua-Tape-1-89-in-x-50-yd-322-Multi-Purpose-HVAC-Foil-Tape-1207792/100030120

Wiki: https://en.wikipedia.org/wiki/Duct_tape "...Another variation is heat-resistant foil (not cloth) duct tape useful for sealing heating and cooling ducts, produced because standard duct tape fails quickly when used on heating ducts...."

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  • Thanks for the reply. Jack is correct the mastic/duct butter is preventing good adhesion with duct tape. I tried that first and should have mentioned it.
    – For the Name
    Commented Apr 10, 2020 at 15:25

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