Aluminum Duct Tape Doesn't Stick

After exhausting all dealer remedies, have you considered using old fashioned duct tape?

Or, maybe big plastic wire ties to secure the tape?

I would never attempt this, but you could lay a ply of glass cloth and polyester resin around the whole thing. Or maybe just glass cloth tape?

Glass cloth adhesive tape with high temperature and flame ..

Sounds like you may have contaminated duct work. Solvent clean everything?

Thanks lynlynch for your input.

I've thought about some of your suggestions but I think that maybe the installers used the aluminum tape because of the local code requirements here in Florida. I am concerned about using alternate methods that may not meet the code. (Usually there are good reasons for following the codes.) I'm wondering if the aluminum tape you buy now is made offshore (guess where) and the adhesive does not withstand the combination of vibration and temperature.

I will look up the local code and see what the requirements are (if any). If the aluminum tape is not specified, I will follow your suggestions.

Thanks again,

OldEngr

Regular hardware store "duct tape" is not designed for sealing duct-work, and will not last for very long; a few months, at best.

If the aluminum tape isn't adhering, there is probably something contaminating the surface (dirt, oil, etc.). Remove the old tape, clean the surface with alcohol, or something that won't leave a residue, install fresh tape.

Try the self stick silicone tape thats out on the market. I cures to itself and has great resistance to weather & atmosphere.

I have two thoughts about this. 1) the tape may be old, been exposed to excessive heat, or of poor quality. and 2) the duct may be contaminated with an oily substance.

Florida does indeed have strict code requirements for the tape used. If I was you, I would wash the duct surface with mineral spirits, brake cleaner or some other similar product. Probably a couple of times. The tape is available in wider sizes also. Go to a commercial A/C refrigeration supply house, or a local Grainger location and buy some quality tape. There is also a sealing compound that will bond, seal, and insulate the joint. Good luck.

In addition to cleaning the surfaces I would extend the tape further from the joint in both directions with a couple of layers because it may be under some mechanical stress spread the stress further.

Thanks for your comments..

Maybe I should call the service company back and make them fix the problem!

OldEngr

A call to the building and zoning department might help with identifing the markings on the tape. It is marked on the face just so the inspectors can ID the tape used.

The seal between plenum and duct interface is normally done with silicone or rubber. Tape will never work longer than it takes to drive away from your site. Insulation liner is normally duct taped with aluminum tape on the outer form.

"The seal between plenum and duct interface is normally done with silicone or rubber. "

Not according to the South Florida Building Code.

I was one of the people that had no use for all of the interference that those codes forced on homeowners...until the hurricanes hit us. A fence blown down? Found out it was not installed to code. Roof damage? Not to current codes. Current codes have made buildings much more resistant to the damages of hurricanes. If the code requires a certain design of tape to be used, It is probably because it works for the designed project.

Hi,

I am a retired Florida Licensed Building Contractor. I don't remember the name of the substance, but there is a rubbery substance that is painted onto the exterior if the duct and plenum joints that helps to seal and reinforce the taped joints. I had to have this done in my own house about 7 years ago. Good Luck!

TMF

The material is called Mastic and it's the correct way to seal joints in duct work. It usually has fiber mesh in it and dries rock hard. This is spec on commercial jobs.

It is from Durodyne.

If you mean, the fabric based silver coloured duct tape, than that is that last thing one should used for duct work. It is meant for anything other than sheet metal duct work.

If you mean, the aluminium foil adhesive tape, as per "3M", the biggest problem with this item, is the term "pressure sensitive". When applying the tape, it must be forced tight against a clean, non oil free surface.

1: The surface must be clean of oil and debris. Not likely from the fabricator, but a simple wipe from a clean dry cloth works well.

2: When applying the tape you "must" use direct pressure to the tape to adhere it to the sheet metal. I use a plastic smother tool, usually supplied from the manufacturer.

3: If the contractor had actually done its home work, and went to the web site, and read the recommended instructions. You would not be posting this.

My guess is that you found a mixture of tape that could not stick too glue, mixed with bits and pieces of tape, that could not removed with a chainsaw.

You can try canvass cloth. Or Seal the joint with proper sealing compound. At the joints the sheets should liberally overlap

Having designed and built air handlers, the most common problem today that cause this a lot is "being green" and considering my company is a green energy venture you may not expect to hear this from me. However common sense rules our firm, not public perception. "don't cool the rooms you arent in" they cry...... "dont heat the rooms you arent in".... they cry there is a mechanical flaw to this logic, all air handlers from domestic to commercial though having a thermal control do not have an airflow control, so when you shut off the vents in other rooms, the air pressure increases in the ducting, the low setting for the fan has to have the ability to push air into every single room there is ducting at the same time if they are all open, so what do you think happens when you close most of the vents to "be green" or even just to save energy costs? of course this pressure will blast out of the open ducts, but like all plumbing, the pressure must run through the system first. Often people will close a duct and go and open another hwne they change rooms leaving the entire system closed and looking for a pressure release point.

Metal duct? use a metal collar and heat rated silicone or silyl modified polymer (Thats what we use) foil duct have joiners that can be ring clamped or wired, usually a foam seal sits under this so it can be accessed.

I have seen some service tech used cable tie to hold the duct to plenum and use the duct tape to seal the duct. it makes sense since the cable tie will help to strengthen the joint and duct tape to seal the joint

For me duct tape is good if it does not have to be permanent. For good reliability I would use a metal collar. The advantage is that you can tighten it as much as you want and is removable in case you want to clean the duct; also the collar is reusable, unlike the tape.

I would suggest that you use tape designed for use with car exhaust piping if this does not compromise some regulations in your local area.

This type of tape is heat resistent and have proved to have positive "sealing" effects.

Hope you figure this out, good luck.

Markar is right. Mastic will remain flexible. It's stronger if used with cloth/mesh tape. I've never seen it come apart. Since you're in Fla, I'm guessing that the failure of the aluminum tape is probably due to a combination of high humidity and possible condensation under the tape causing it to come loose. You don't want to clean it with mineral spirits or paint thinner, it will leave an oily residue. Brake cleaner or alcohol will work best.

Here is a reference:

http://oikos.com/library/ducts/index.html

clean the unit, re apply the tape then put a wrap of plastic banding strap over the seams where it loosens. easier & cheaper than tie wraps.

I worked with a commercial installer of HVAC for a while helping him out with heavy work loads. We used this type of tape and he had me rub over the tape real good using the waxy like paper backing all over the tape pressing it down to assure good contact and sealing. This tape he used was delivered by the company that custom made the duct work but was a purchased item from a supplier that I don't remember the manufacturer's name. We used this on the insulation wrapping. For the metal duct work, we applied with a small paint brush a paste like compound that would dry and seal. We used this to coat all of the joints. We never applied the tape directly on the metal duct work, so maybe there is a reason for this as you are experiencing now. I would go to you local building supplier and see if they carry duct goop (no better term right now), get a small paint brush and coat all of your seams with that.

Ditto. Buy the good stuff with the silicone adhesive and pay careful attention cleaning all the surfaces with rubbing alcohol before applying (see previous posts). The HVAC hacks just slap it on because if it lasts for a year, they're in the clear.

Nashua is one brand that works very well. It's expensive, about $20 for a roll about the size of typical duct tape that you shouldn't use for ducts. I've even used it to repair small tears in the rubber roof of my travel trailer. Works great from screaming hot summers to bitter cold winters.

Good preparation is always 95% of any job and pays huge dividends in the end.

The foil tape that you used was pressure sensitive. The installer knew his stuff, as did the fabricator of the custom duct work.

The aluminium foil tape you used, needed the pressure to adhere.

As for the "Goop", it was probably a water soluble green coloured compound from "Durodyne".

Buy glue from custom Nano Technology will cost about $25.00 take a paint brush apply on sticky side and apply it will work

http://www.shurtape.com/Default.aspx?Tabid=79&MLevel1=73&MLevel2=86&MLevel3=87&ProductID=30

That is the URL for the tape we use to repair connections on flex ducts. Once the repairs are made and they are re-sealed, we then coat the units (Paint them with a sprayer if you will) with our insulating ceramic coating. It is an elastomeric and in most cases drops the homeowners electric bill by around 25%.

If you have to seal the units anyway, why not add insulation value to it at the same time? We started coating / insulating attic equipment around 4 years ago. We have never had a call back or complaint with the exception of one; one of our guys slipped and stepped through the the sheetrock. OOPS, had to make those repairs. :)

I have a few pictures of a completed job on our site.

www.ct-texas.com

As far as heat sealed goes, glue guns with glue sticks loaded in them heat-up.

I wonder why they didnt use Duct tape.ds

There is cheep foil tape and there is the good stuff, go to your local HVAC supply house and get the good stuff or get duct seal that comes in a pail that you wipe/trowel on.

Take the old tape to the supply house so they can better understand and give you advice on why the tape is releasing.

Is the tape releasing from the insulation or from the air handler, is this the indoor coil section?

You could have a condensation problem that is the cause of the releasing tape, is this outdoors,is there a lot of movement at this connection between the duct work and unit?

There are different tapes for the job and most contractors will use the minimum tape that code calls for because when they pick up there supplies they just want "code" tape.

If you go buy yourself the good stuff expect to pay $20-$30 or better per roll for it.

I hate to ramble but so many questions come up as I write this.

Go to your local HVAC supply store ( not LOWES or HOME DEPOT) and get either mastic tape or mastic. Ask the guys there how to use it.

Duct tape comes in different grades...

To get the best, make sure it is Nuclear quality Duct tape... This is the strongest and holds the best...