Connecting heater ducting together

[Eweneek1]

Replacing a branch line in my forced air heating system due to the age and condition of pipe. Complete duct system is 26 gauge round metal. Bought new pipe and wyes and now putting it together. All the piping lengths have been snapped together. Having trouble with the pipe going into the crimped end of wyes the full 1 1/2". Working in a crawlspace with pipe hanging from floor joists.
Any suggestions?

 

[Dana]

Some pictures would be useful.

How far in CAN you get it? (Enough to stitch it with a couple of sheet metal screws, perhaps?)

Once it's all hooked up trowel/paint at least 1/8" thick duct mastic to every joint & seam, especially the joint that you can't seem to fully seat. Without sealing it this stuff leaks a lot more than intuition lets on, and the crawlspace is neither the intended source or destination of air in your HVAC system. Most tapes don't cut it either. Temperature rated aluminum tapes can, but only when applied to shiny-bright sheet metal and burnished-in a bit. Mastic is still more reliable over the long term.

 

[Sponsor]

 

[hj]

It may be a misstatement, but pipes go OVER the crimped ends of joints and fittings.

 

[Eweneek1]

It may be a misstatement, but pipes go OVER the crimped ends of joints and fittings.

You are correct HJ. I meant pipe onto the crimped end. Have some new Standex 10" pipe and which goes together very easy all the way to the stop. I really have to force this new duct and fittings together and it goes together about an 1" which is probably OK. Maybe I should do a little extra crimping on the difficult ones. Added three photos. One and two are the problem ones, and the third one is the Standex fittings.

 

[Eweneek1]

Some pictures would be useful.

How far in CAN you get it? (Enough to stitch it with a couple of sheet metal screws, perhaps?)

Once it's all hooked up trowel/paint at least 1/8" thick duct mastic to every joint & seam, especially the joint that you can't seem to fully seat. Without sealing it this stuff leaks a lot more than intuition lets on, and the crawlspace is neither the intended source or destination of air in your HVAC system. Most tapes don't cut it either. Temperature rated aluminum tapes can, but only when applied to shiny-bright sheet metal and burnished-in a bit. Mastic is still more reliable over the long term.

 

[Eweneek1]

Goes together about an inch if I apply a lot of pressure. The ducts I removed were 30 gauge and undersized. Think they were made by a company called Wilmade. Photo attached. Installer put system together with duct tape and a few screws, no mastic about 25 years ago. Ducts were leaking, filled with a lot of dirt and other debris, and rusting in certain sections. Plan on using Nashua 324a tape, mastic, and insulate with R6 duct sleeves. Replaced all the floor vents with Speedi Boots and Reggio registers.

 

[Dana]

^^A couple of screws and ample duct mastic worked into the fluting and over the whole edge should handle that.^^

Nashua 324A would be fine for long straight seams of shiny-new galvanized, but mastic would be the ticket at all joints, including the slip joints on the ells.

How air tight do the gaskets on the Speedi-Boots seem? I've never used them myself, but could believe they'd do a decent job sealing to plywood.

 

[Eweneek1]

^^A couple of screws and ample duct mastic worked into the fluting and over the whole edge should handle that.^^

Nashua 324A would be fine for long straight seams of shiny-new galvanized, but mastic would be the ticket at all joints, including the slip joints on the ells.

How air tight do the gaskets on the Speedi-Boots seem? I've never used them myself, but could believe they'd do a decent job sealing to plywood.

 

[Eweneek1]

The Speedi Boots seal very well. I removed the adjustable brackets and mounted directly to the sub floor using Kreg 3/4" pocket screws in each corner of the boot.