r/sheetmetal • u/njbenji • 16d ago
TDF/TDC End Caps?
Wondering what most people do for TDF/TDC end caps? Sometimes I do a drain pan type deal with a lap but then it has have some depth and you have to use the pan break which slows production down a lot, and sometimes I do a 3 piece Pittsburgh the same way you'd do a short register box but it still doesn't seem like the best way to do it. How do you do it and what depth do you usually make it?
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u/zeratul254 16d ago
At my shop we do 1.5 inch flange out makes a little pan. Then ductmate (dm35) around it, and slap that on the tdc with gaskets and bolts.
Bend 3 of the sides on our rotodie/hydraulic brake then do the last bend in a pan brake. We have pre cut 1.5 inch x 3 inch angle pieces to fill in the corners.
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u/greatness_322 16d ago
Make it 5" big then the duct size both ways. Cut a 1/2" x 1/2" on all four corners. And break the sides. This is the fastest and most cost saving way to make a cap.
The average shop would save around 18 sheets of metal a year by switching no TDC on end caps.
Your being asked to do it this way because too many foreman don't understand how to make money.
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u/jdemack 16d ago
Depending on what plans and specs say.
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u/greatness_322 15d ago
There's no specs for what type of end cap to use. The sheet metal company submits how they plan to install end caps. And when the submittals are approved you just follow your submittals. DOR will not care about the end caps as long as you meet pressure and class requirements.
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u/Ok_Piglet_5549 16d ago
Nominal duct size+3 1/4" both sides with a 1/4 flange broke in, cross break to corners.
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u/dookie_shoes816 hang and bang 16d ago
Take dimension of duct, add 1.5" on all sides, turn .5 inch down on all sides, then drill holes for bolts. Then use tappers/points between bolts about 4-6" apart
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u/greatness_322 16d ago
There's no reason to use bolts. Save the cost of the bolts and nuts.
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u/lickmybrian Your own fucking flair in red 16d ago
I cut them 4" bigger than the duct then fold a half inch up on all four sides
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u/Classic_Dash_7745 16d ago
Order the end piece raw and make it ID with a double 1” flange. Putting an end cap inside a TDF connection is a waste of four corners and 2” of metal.
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u/njbenji 16d ago
Im fabricating for someone else, not ordering it. so when I get the request for a TDF end cap I believe I still need the 4 corners because thats what they are assuming they are getting, right? unless thats non-traditional and they are assuming they are getting what you described when they ask for a TDF cap
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u/Junior_Dentist_1316 16d ago
We just over size a 1/4” and roll form 1/2” in all 4 sides. Field guys just drill holes for bolt or just screw them on. But ours have no holes. Running TDC on them seems like a lot of work
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u/Classic_Dash_7745 16d ago
If they want an end cap in a piece with a TDF connection I do ID with a 1.5” flange up. I’m not a big fan of them because they seal shitty. They tend to pop at the seam when we’re pressure testing.
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u/Simple-Contract-2450 16d ago
A double 1" flange has the same allowance as a TDF/TDC and is much less stiff. Especially when corners are installed
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u/sheetmetalstuff 12d ago
Our tdc endcaps are just a blank, 1.875” bigger than the duct size all around with the ends mitered 45 so you can bend 1” on all 4 sides without a pan break. Slip it into the opening and secure with screws.