Results 1 to 7 of 7
  1. #1

    Going from 10" flex to 12"???

    Hello,

    Newbie here and before I post my question, let me give thanks in advance to those who will take the time and provide an opinion/suggestion, I appreciate it. Now on to my question, I'm replacing a 6' flex duct (10") and when I try to put on the new flex duct the fit is very tight. I've done some research and applied mastic at the joint, but when I try to put my flex duct over my duct, it just wont go over it easy. My question is, would my system suffer if instead I put a 12" flex duct since that one will give me more room and after applying mastic at the joint areas, followed by a zip line and then sealed with tape I imagine that finish would be pretty air tight. Any suggestions/tips are welcome.

  2. #2
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,430
    Quote Originally Posted by snakeo2 View Post
    Hello,

    Newbie here and before I post my question, let me give thanks in advance to those who will take the time and provide an opinion/suggestion, I appreciate it. Now on to my question, I'm replacing a 6' flex duct (10") and when I try to put on the new flex duct the fit is very tight. I've done some research and applied mastic at the joint, but when I try to put my flex duct over my duct, it just wont go over it easy. My question is, would my system suffer if instead I put a 12" flex duct since that one will give me more room and after applying mastic at the joint areas, followed by a zip line and then sealed with tape I imagine that finish would be pretty air tight. Any suggestions/tips are welcome.
    No, you would have a huge gap and it wouldnt hold properly. you may need a crimping tool but it usually slides right on without a crimp. Mastic lubes it up and makes it easy, yet messy. Most manufacture tape the inner wire to the black plastic which can sometimes make it difficult.

  3. #3
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    16,068
    Quote Originally Posted by jtrammel View Post
    No, you would have a huge gap and it wouldnt hold properly. you may need a crimping tool but it usually slides right on without a crimp. Mastic lubes it up and makes it easy, yet messy. Most manufacture tape the inner wire to the black plastic which can sometimes make it difficult.
    Wow! you get a gold star for just being able to interpret what his question was.

    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  4. #4
    Thanks much for the information. I will go back up there and do my best to make fit nicely.

  5. #5
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,430
    Connecting flex can be tough for a novice. You have to hold the weight off of it and line it up straight then it should slide right on. If there is any old tape or adhesive or dried mastic still on the duct connection it can make it real tough, especially old sticky tape adhesive.

  6. #6
    Jtrammel,

    Thanks for the tip, I was able to do the install. First, I applied mastic to the surface of the supply line where I connected my flex duct. After I was able to slide my flex duct over the round metal supply line, i secured it with a zip line, pulled the insulation over joint connection, covered that with silver tape and then mastic over the tape. Turned the unit on and it seems to be working fine, at least for now. I'll check on it periodically just to make sure the end joints haven't come apart. Thanks again.

  7. #7
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,430
    Quote Originally Posted by snakeo2 View Post
    Jtrammel,

    Thanks for the tip, I was able to do the install. First, I applied mastic to the surface of the supply line where I connected my flex duct. After I was able to slide my flex duct over the round metal supply line, i secured it with a zip line, pulled the insulation over joint connection, covered that with silver tape and then mastic over the tape. Turned the unit on and it seems to be working fine, at least for now. I'll check on it periodically just to make sure the end joints haven't come apart. Thanks again.
    Sounds like you got it right. Glad you got it on.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event