I'd like to run some duct tape to wrap slightly around the edge of the drywall onto the painted ceiling to seal this.

++>> a picture might be worth a thousand guesses ..

what about something like at the link ... i used it as an edge to drywall in a certain application ...

ken

Duct tape is good for just about anything other than that for which it is named. In an HVAC application it will generally blow away in about 90 days. That is for the good tape. ER is right on the money with his suggestion and experience.

Thanks for the info.

Just to confirm your thoughts: Is this a completely different tape then the HVAC foil tape sold at the big box stores like Home Depot or Lowes? Would those work for me?

you are welcome.

Hardcast 1402 is not sold at box stores
it is a hvac supply product.
foil tapes won't adhere to the sheetrock
and the metal flange. mastic tape will.
as you can see in pic it is silver with red
writing.
box stores may carry Nashua brand mastic tape
an inferior product in my experience.
mastic is thin, adhesion is not as strong.
not worth the labor to replace when it fails IMO.

here is an ebay link..not where I purchase from...
but quick google search of product:

http://www.ebay.com/itm/HVAC-Hardcast-AFG-1402-Rolled-Mastic-Duct-Sealant-Tape-3-x100-Topmost-Quality-/321032199173

take a look at the link..so you'll have an idea of what
the roll looks like. not silver with blue writing...red writing..
other types do not seal long term

pricy, but worth it as it lasts...according to johnston supply specs for 40 years. I can only vouch for 15
years when I first started using Hardcast.
I have a real problem with having to go back & re-work
previous work..thus the use of this specific brand of
specific tape.

if surfaces are clean & dry...it will seal to just about
everything, stucco, cement & dirt excepted.

once you use this product...you'll use it for
lots of things.

best of luck.

We followed energy-rater-la's advice and sealed all of the indoor duct boots to our drywall plus the mastic on the inside of the duct boots. We picked up the tape at Ferguson's / Air Cold Supply in Phoenix. I just walked into the supply house, picked up the tape and paid cash. Roll of tape was $80 and the CCW mastic was about $20. We ended up using 2 rolls of the tape and a few buckets of mastic - but we have (2) AC units and lots of ducts.

We took our time and sealed a few duct boots and registers each weekend.

WOW! ... Noticeably less dust in the house. We can really tell the difference in our master closet where the dust would collect on our clothes. Less dust in the filters, too. We've also seen our AC usage drop by roughly 20%.

What a great, easy to implement home improvement!! Paid for the mastic tape in 1 month. We could not be happier.

Thank you energy-rater-la.

great! and kudos for using the right product.

prices sure are higher in Phoenix for mastic tape!