# Metal ductwork with few tools



## dielectricunion (Feb 27, 2013)

I'm planning to fabricate the plenum and trunks for the gas furnace at my own place. I bought full sheets of 24 ga galvanized and I'm going to rent a 10'6" brake for the day.

Without a Pittsburgh or other seaming equipment, is there a decent joint that I can use for my rectangular boxes?

I will, no doubt, struggle with this small project, but I've already committed myself!


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## Randy Bush (Mar 7, 2011)

dielectricunion said:


> I'm planning to fabricate the plenum and trunks for the gas furnace at my own place. I bought full sheets of 24 ga galvanized and I'm going to rent a 10'6" brake for the day.
> 
> Without a Pittsburgh or other seaming equipment, is there a decent joint that I can use for my rectangular boxes?
> 
> ...


Something I have done before is to hem and reverse hem the pieces to put together then use short screws. That 24 ga will be a little tough bending, but doable especial if you can fasten the brake down. and keep the pieces shorter in length.


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## Inner10 (Mar 12, 2009)

dielectricunion said:


> I'm planning to fabricate the plenum and trunks for the gas furnace at my own place. I bought full sheets of 24 ga galvanized and I'm going to rent a 10'6" brake for the day.
> 
> Without a Pittsburgh or other seaming equipment, is there a decent joint that I can use for my rectangular boxes?
> 
> ...


Just phone in the measurements to an HVAC supplier and they have a big fancy machine that will make the plenum, it's cheap as fvck. It's probably more expensive to rent a brake.


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## griz (Nov 26, 2009)

here ya go...:laughing::whistling


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## dielectricunion (Feb 27, 2013)

griz said:


> here ya go...:laughing::whistling




What does the "brite" do?

I love the infomercial where they drill holes in the boat and seal it with that crap!


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## dielectricunion (Feb 27, 2013)

I just ended up using that lap-half lap. Seems to work pretty well, thanks!










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## 37-Flash (Aug 14, 2016)

This is an in-valuable tool for otj sheet metal. 
http://www.homedepot.com/p/Klein-To...8EYT4Aism7s9Icchdm8bEaAnSo8P8HAQ&gclsrc=aw.ds

S-lock and drive cleat, at the joints. Good job with what you did, but maybe next time, fold the edges with about 5/8" lips, and/or channels for drive cleats.


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## Inner10 (Mar 12, 2009)

37-Flash said:


> This is an in-valuable tool for otj sheet metal.
> http://www.homedepot.com/p/Klein-To...8EYT4Aism7s9Icchdm8bEaAnSo8P8HAQ&gclsrc=aw.ds
> 
> S-lock and drive cleat, at the joints. Good job with what you did, but maybe next time, fold the edges with about 5/8" lips, and/or channels for drive cleats.


I didn't even know there was a different way to do it.


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## Anthill (Mar 23, 2013)

a Pittsburgh lock is quite doable on a brake. Its also much tighter than that fold you did. I've done it many times on site in a pinch.

Also 28ga or even 26 ga would be much easier to work than 24ga. 

Like Inner implied, in standard sizes it is cheaper for me to purchase pre-formed ductwork that to buy the flat metal, let alone form it. (and I have a Pittsburgh machine)


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## Anthill (Mar 23, 2013)

Is the 10-6 brake an aluminum flashing brake? 24ga steel might stretch its capacities a little.


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## beenthere (Mar 5, 2009)

Hope you cross broke that duct, or even at 24 gauge, you'll get banging noise.


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## dielectricunion (Feb 27, 2013)

Yeah I tried to cross brake all the wide sides (a few I forgot to do before bending)

I did leave a 1" lip for S lock and roll over the perpendicular end to join with drive cleat


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## A&E Exteriors (Aug 14, 2009)

What is this Pittsburgh lock? 
I have a roll of 29g painted steel coil I could bend this stuff for my addition.


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## MechanicalDVR (Jun 23, 2007)

dielectricunion said:


> I just ended up using that lap-half lap. Seems to work pretty well, thanks!
> 
> 
> 
> ...


Hate to be critical but that is a pretty lame joint. 

Could have gotten a knock down plenum for a whole lot less aggravation. 

Were you able to make a door for the 'A' coil?


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## MechanicalDVR (Jun 23, 2007)

A&E Exteriors said:


> What is this Pittsburgh lock?
> I have a roll of 29g painted steel coil I could bend this stuff for my addition.


A Pittsburgh lock


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## A&E Exteriors (Aug 14, 2009)

Mech Diver said:


> A Pittsburgh lock


Thanks. I think I could handle that


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## dielectricunion (Feb 27, 2013)

Mech Diver said:


> Hate to be critical but that is a pretty lame joint.
> 
> 
> 
> ...




Sure, it's definitely a lame joint, but this is the first time I've ever worked wth sheet metal and I only rented the brake for a day. I guess I'll just say, it worked, and I hope to do better if I ever do it again.

I don't have an AC hooked up so I just built a box that should be similar in size to the coil I'll eventually install so I can remove it and modify. We'll see how that goes!

Let me know what you mean by a door, maybe it's too late for that.


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## Inner10 (Mar 12, 2009)

dielectricunion said:


> Sure, it's definitely a lame joint, but this is the first time I've ever worked wth sheet metal and I only rented the brake for a day. I guess I'll just say, it worked, and I hope to do better if I ever do it again.
> 
> I don't have an AC hooked up so I just built a box that should be similar in size to the coil I'll eventually install so I can remove it and modify. We'll see how that goes!
> 
> ...


By door he means you cut a big hole then tape the piece back over after jamming in the N coil.


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## Anthill (Mar 23, 2013)

might as well wait till coil day to make a door now. It's no more work to do it later.


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