## IMPORTANT ! Metal Ductwork - Does it rust easily?

[Allan Speers]

This is an odd question, but -

I just got my neighbor's Onieda Cyclone & extensive metal ductwork back to my house. I am currently doing massive repairs to the house & shop, which means I cant' put it all up for a while, and space is currently non-existent. - But the price for all this stuff was too good to pass up (as in FREE! :) ) so I brought it back.
I also need my truck for work, so yesterday I piled everything up, except for the blower unit, in my backyard.

Of course, today it's raining heavily.

I'm not worried about the tubing, since the coiled metal part is in encased in a rubbery material.

- but the ductwork? It's standard HVAC stuff.
It looks like galvanized steel, but I've heard of HVAC ducts rusting in houses, under really bad conditions.
-----------------------

SO:

Should I be worried? Can this stuff stay outside for, say, a week or two?

[Andrew Seemann]

If it is galvanized and in good condition, it won't rust for a while, definitely not for just a few rainstorms. As long as it dries out, it shouldn't rust for quite a while. That said, I wouldn't leave it out longer than you need to, so it doesn't get standing water in it. Not so much for the rust, but the gross things that grow in standing water, although the zinc will probably slow that a bit.

[Allan Speers]

Thanks, Andrew.


Note: I'm just ASSUMING it's galvanized, as it looks it. Would that be expected with "standard" HVAC ducting?

[Jim Becker]

I actually hope it's heavier than "standard " 30 gage HVAC duct work...like 26 gage stove pipe. :) But relevant to your question, mine has been in place since the early 2000's with zero corrosion.

[Marc Jeske]

Cover it w a cheap but new ( no leak ) tarp ... arrange for venting... and don't worry about it.

Marc

[Andrew Seemann]

Note: I'm just ASSUMING it's galvanized, as it looks it. Would that be expected with "standard" HVAC ducting?

I don't remember the last time I saw any ungalvanized HVAC ducting. My house is from 1975, and even those ducts are galvanized.

[Allan Speers]

Thanks, guys.

[Matt Mattingley]

The sheets are galvanized prior to sheer and form. Any exposed edges or scratches will take on rust.... this is normal! Metal having a high resistance to temperature change is prone to oxidization. So… Bare metal should be treated. Your car would probably rust from new if it wasn’t painted and under coated.

[George Yetka]

If its Spiral that stuff comes with what I believe is fish oil on it which will offer some protection. Im not 100% it may just be the oil they use to form it, but there is definitely something.

Lightweight house duct has a light galvanizing but will rust at the seams/cuts.

Either way keep it off the ground and cover it when its completely dry.

[Jim Dwight]

If you have a crawl space or attic, they would be better places to store the stuff than the back yard. I do not think it will fall apart but if the inside gets a bit rusty it will decrease airflow.