Duct Boot Connection

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  #1  
Old 12-31-17, 02:39 PM
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Duct Boot Connection

Connecting a 3.25" x 10" duct boot to a 3.25" x 10" rectangular duct and have about a 1/4" gap on either side. Do I bend the tabs of the boot over top of the rectangular duct then tape the crap out of the joint? Or is this boot not the correct part? It says 3.25"x 10" on the UPC sticker.
 
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Old 12-31-17, 02:53 PM
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I think normally you put duct cleat s-connectors on all 4 sides and then one slips into the other and you tape it or brush mastic over it.
 
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Old 12-31-17, 03:01 PM
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Okay. I believe I'll still need to bend the tabs to get them to fit, but I guess that shouldn't be a big deal. There are flanges already built into the longer sides--does this mean I just put S connectors on the two shorter sides? Or should I cut off the factory flanges and do S connector all the way around? Here's an overall of the boot...
 
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Old 12-31-17, 03:10 PM
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You buy a piece of s-connector, cut it to length, and put it on the short sides. You can put it on either side if needed... inside or out. Male or female.
 
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Old 12-31-17, 04:52 PM
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Got it, thanks.

I can use the S connector to support the duct in between the joists correct? Or is there a better way?
 
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Old 12-31-17, 05:08 PM
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You mean like a strap? I suppose you could.
 
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Old 12-31-17, 07:31 PM
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Sorry, I'll admit I'm a little ignorant when it comes to HVAC work.
 
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Old 01-01-18, 05:27 AM
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The fittings you buy from the big box stores are sold to be finished by the installer. The short ends of the duct and the fitting are supposed to be bent over into a "U" so that they can accept what is called a "drive fitting" to lock both pieces together. The long side uses an "S" slip as the picture shows. I knew the connection as a "slip and drive"..If you can't do a "slip and drive" you could use a pop rivet gun to connect the fitting to the duct at the short end and the long side uses the "S" slip and usually no duct tape is needed.
 

Last edited by Steamboy; 01-01-18 at 05:29 AM. Reason: finish sentence
  #9  
Old 01-06-18, 06:48 PM
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Thanks fellas. I picked up a bender, hand seamer, and some S cleat and drives and finished all the connections this afternoon. Only think left to do is connect the duct to the main trunk. I have a square to 6" takeoff and am a little confused as to the best way to connect this thing. I can only access the trunk from one side and the duct is going to run the opposite direction. Therefore, it's impossible to to get my hand inside the fitting to bend the tabs. I can't get a drill in there either and even if I could, I doubt the screws would grab. What should I do? Push it in the best I can then seal the crap out of it with mesh tape and mastic?
 
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Old 01-06-18, 09:17 PM
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You cut your opening in the trunk and then you put your takeoff in with the tabs inside the trunk. Then reach inside the take off and bend the tabs in to lock the takeoff in place.

Once the takeoff is installed you install the rest of the 6" line to it. You work from the trunk to the register.

If you already have all the pipe hooked up from the register back to the trunk they have round takeoffs that are stickons so they mount right to the face of the trunk and then you use screws from the outside also. They come with or without a damper.

https://www.homedepot.com/

Type the description below in the search box to see what is available. H.D. is just an example. I'm sure other box stores have too.

6" diameter galvanized takeoff with gasket

Hope this helps a little.
 
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Old 01-07-18, 06:55 AM
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Thanks for the tips. However, I cannot access the opening of the boot in order to bend the tabs. The opening is facing away from me and I'm working in a very restricted space. A side takeoff is not an option. Perhaps I could use some strong double-sided foam tape to secure the boot then mesh amd mastic to seal it?
 
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Old 01-07-18, 07:04 AM
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If you have enough room to cut the hole, you should have enough room to bend the tabs on the starting collar. They do make starting collars that just stick on the outside of the trunk with foam tape and screws, but I have not seen them at the home store. Only special order.
 
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Old 01-07-18, 07:14 AM
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I seriously do not have room to reach in there. It's the rectangular to 6" right angle zero rise style and there is also another takeoff next to it. Otherwise I could maybe contort my arm enough to maybe reach in.

Something like this perhaps : http://www.gorillatough.com/gorilla-heavy-duty-mounting-tape?&mkwid=s4kDE8IBv_dm&pcrid=103675260086&pmt=b&pkw=tape sticky on both sides&mslid=&pgrid=39015144691&ptaid=kwd-298253577756&gclid=EAIaIQobChMIuNOtp4nG2AIVD0wNCh2bfgHoEAAYAiAAEgK5CPD_BwE
 

Last edited by mossman; 01-07-18 at 07:36 AM.
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Old 01-07-18, 07:36 AM
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This is similar to what I was referring to: http://www.snappyco.com/products/gal...offs-adhesive/

That foam tape you linked to is not very good and would likely only last one season. You would be better off attaching it with aluminum foil tape and mastic.
 
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Old 01-07-18, 09:07 AM
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Thanks for the link. I'll give this one a try: Adh Takeoff Top Adj | Snappy Co.. Hopefully they will fulfill such a small order, and to a homeowner at that. I had to email a sales rep to inquire.

A circular collar would be fine, but I only have about 9" of headroom between the duct and subfloor. I'll make a trip to the hardware store to see if they have a 6" elbow that is this low profile.
 
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Old 01-07-18, 09:10 AM
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,T,
Read post #10.

M,
I can't picture what you have but if you had access to the other side of the duct would that help?

If it would enable you to get your arm in there, it sounds strange but you could cut another opening large enough to give you access to the tabs and then get a piece of PANNING, which is just a piece of flat sheet metal, which you can buy the same place you get your duct work. It comes in small lengths and you cut to size to seal the extra opening to make sure your takeoff is in secure.

Just a thought,

Hope this helps a little.
 
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Old 01-07-18, 09:29 AM
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M,
I can't picture what you have but if you had access to the other side of the duct would that help?
Working on it...

If it would enable you to get your arm in there, it sounds strange but you could cut another opening large enough to give you access to the tabs and then get a piece of PANNING, which is just a piece of flat sheet metal, which you can buy the same place you get your duct work. It comes in small lengths and you cut to size to seal the extra opening to make sure your takeoff is in secure.

Just a thought,

Hope this helps a little.
That's a good idea, but that isn't possible.
 
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Old 01-07-18, 09:33 AM
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Here's a pic of what I'm working with. I cannot reach from the opposite side--it's about a 4 ft stretch, very low headroom, and the rails from the drop ceiling are in the way. As you can see, I already cut the rectangular hole. It is 6-1/2" x 7", so I could still use a circular takeoff and be able to seal around it sufficiently. Question is the headroom (less than 10").
 
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Old 01-07-18, 12:06 PM
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m,
The fitting that Tolyn mentioned sounds perfect for your needs. If you can not get it and have to use what you have my suggestion would be to cut off the tabs on the side of the takeoff that the air is flowing for less resistance to the pipe.

Next, I would forget the mastic and use aluminum foil tape, not duct tape, foil tape which doesn't dry out or break down.

I see in the pic it looks like a top take off and I assume to cannot get to the bottom either so if you cannot get what you need from Tolyn's sight if you google the heading below it will give you other possible buying options.

6" galvanized self sticking sheet metal takeoffs.
 
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Old 01-07-18, 12:26 PM
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I have a roll of Nashua tape, which is supposedly the good stuff. However, I wrapped the takeoff seen in the picture a couple years ago and the tape is lifting off. Maybe I didn't clean the surface well enough. Thought I did.
 
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Old 01-07-18, 05:23 PM
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I thought about getting a round elbow so I could bend the tabs back with the fitting facing me, then rotating it the opposite direction, but then I wouldn't be able to screw the duct to the fitting. Looks like an adhesive style takeoff is my best bet. BTW, I would cut a hole in the sheet rock and duct from below but I'd rather not cut the sheet ock because it is a textured ceiling.
 
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Old 01-07-18, 07:51 PM
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I was able to improvise...I picked up a 6" split collar and elbow, flattened the locking tab on the collar and cut the slit deeper so I could slide the elbow all the way over, which barely gave me enough headroom. I fastened the collar in place first, the elbow to duct on the floor, fed it up through the ceiling and slid it over the collar. I could barely get it on, but I managed. Everything is secure and sealed up. And I can now check it off my list!
 
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Old 01-08-18, 12:55 PM
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Congrats on a job well done. Take a rest and relax. You've earned it.

Happy New Year.
 
 

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