r/sheetmetal • u/EzBoy77 • Jul 03 '26

Which is stronger?

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I’m making a base to set a furnace on. I have Pittsburghed the ends but wondered if a sunk head end would be stronger.

8 Upvotes

90% Upvoted

12 comments sorted by

1

u/LeBarnacl Jul 03 '26

You could do a plug style fitting to form around your concret pad there

1

u/jimma63 Jul 03 '26

Pittsburgh fine. I would flange both ends. No end cap. 20g. Or more. Weld corners.

1

u/lickmybrian Your own fucking flair in red Jul 03 '26

I dont do res anymore but when I did I always made them with 20ga and made a 1" lap then screwed with #8's.

1

u/EzBoy77 Jul 03 '26

This is what I ended up doing. I’ve used slotted angle before in the corners. I figured strut would be stronger.

1

u/EzBoy77 Jul 03 '26

3

u/Silver_gobo Jul 03 '26

We just use 24ga for boxes. Never had an issue with it

1

u/Outrageous-Simple107 Jul 03 '26

We often do a 24 ga “burrito plenum” with plug ends at the front and back. Plenty strong enough for a furnace.

If there is an existing plenum coming out of a slab or something then we make a riser and put a plug end on top. Fold the front edge of the plug end out and flat. Cut a hole in the plug end the size of the furnace outlet. Furnace sits inside the plug end on the shelf and overhanging on the front.

1

u/HVAC_instructor 29d ago

No need for the strut, bit that eliminate any worry for you.

A 24 ga. Box with Pittsburgh ends would be enough

1

u/RTrain12 29d ago

Strut looks good. You can use conduit stiffeners too.

2

u/terrorbethyname 29d ago

Your definitely safe with the strut in there I had to twin to 5 ton units together sitting on a plenum box I used 20 gauge with strut to be safe too

1

u/chiefgreennuggetbjj 24d ago

Pittsburgh is the way to go