Necessity is the mother of invention--(NRR)

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luke strawwalker

Well-Known Member
Jan 18, 2009
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Necessity is the mother of invention-- but who's its daddy?? :y:

Keira (my six year old) and I were recently repairing a couple dinged and busted A/C vents in the floor of the house. We also cleaned out some of the pennies and small toys that somehow managed to have snuck through the grates and fallen down into the ductwork, and a few errant dustbunnies that had taken up residence...

I took the wife's handheld bathroom mirror and put it down in the duct, and using a flashlight inspected the ductwork. Everything looked good on one side, but on the other, where the ductwork goes under the wall and floor into the bedroom, the duct was partially pinched shut-- somehow or another, it got crushed (how I have no idea), but it was squashed down til it was only about a 2 inch gap to let air through to the bedroom... (never really noticed it being TOO warm/cold in the bedroom, but then the air from the bathroom returns to the rest of the house through the bedroom, so maybe that was part of the reason-- I DID notice that the bedroom vents didn't ever seem to blow as much as the rest of the house).

SO, the question-- how to "un-crush" the ductwork when it's 3 feet down the duct under the wall and floor of the house (and I DON'T want to have to crawl under there to fix it!) SO, I got a bright idea... I couldn't reach down there and pound it out-- the vent is too tight and my arm wouldn't reach around the vertical riser under the vent anyway and into the horizontal rectangular duct... what I needed was something flexible I could get into position, and then "open up" in the crushed part to "pry" it open again... After looking around, I found an old play ball (Scooby Doo-- you know those little $1 or so round balls in the back of Walmart in the huge rope-lined 'tower'-holder thing) that didn't hold air very well anymore. I got a brainstorm-- if I could *somehow* get this thing in the crimped part of the duct and INFLATE IT, it would "pop" the duct back out to a roughly rectangular shape. SO I started doing surgery on the ball-- tried to remove the valve, but couldn't extract it, so I pushed it THROUGH to the INSIDE of the ball. Tried to open the valve area up by stretching it out with needle-nose pliers a bit, but it didn't work well... no ball inflation needles were around, so I grabbed an old freebie ball-point pen and took the tube off it, and with some twisting and pushing got it inserted into the ball about 2-3 inches deep where the valve had been. Grabbed a 4 foot or so piece of 3/8 acrylic sprayer hose we had for draining the aquarium, and with a couple wraps of duct tape around the pen tube, got a good tight fit of the hose over the pen tube. Couple more wraps of duct tape around the outside of the hose to the pen tube to make sure everything stayed put and didn't blow off while inflating. Decided I didn't want to risk the thing blowing apart in the duct and then having to try to retrieve parts from inside, so SWMBO retrieved an old pair of messed up pantyhose-- tied the legs together in a knot and cut them off, inserted the ball into the HD 'panty' part, and pulled the waistband up snug around the hose and tied it in a knot, making a 'bag' around the ball, pen tube, and hose. Wrapped the excess hose waistband outside the knot around the air hose and gave a couple wraps of duct tape over it to keep the 'bag' securely attached to the air hose.

Went to the shop and aired up the portable air tank from the farm compressor. Now how to get the air from the tank into the ball?? Looked around, and finally saw an old bicycle thrown in the scrap iron trailer to go to the junkyard. Grabbed the valve stem of one of the flat tires and pulled it hard, and cut it off the rim with a pocketknife. Grabbed a small hose clamp and air valve stem tool and removed the valve core from the stem (loosened it up to let the ball deflate easily when desired, yet still able to depress the valve in the hose inflator end of the air tank hose). Grabbed the cable pulling fish tape off the wall and headed home. Inserted the old valve stem in the open end of the hose, and clamped it down tight. Ready to test!

Using Keira as a helper, with the mirror in the duct so I could see down the length of it, and lit by flashlights lying the duct bottom, I hooked the fish tape to the end of the pantyhose 'bag' and carefully guided the thing down the ductwork and into position in the crushed gap. Grabbed the air tank air hose and started airing it up, watching down the mirror/duct. The ball inflated-- crunch, crunch, crunch, and PRESTO! half the duct was now open-- dented and a bit ugly, but OPEN! Let the air out of the ball, repositioned, reinflated, pop,pop,pop, the OTHER half is now fixed as well! Moved down the pipe a bit and repeated several more times in several different positions-- VOILA!

Good as new! (well, good enough). Installed a new floor register and done!


Later! OL JR :)

PS... the A/C guy who we called to add some freon to our system thought it was a GREAT idea... certainly easier/cheaper than replacing ductwork! LOL:)

When you get older they might do that same thing to one of the blood vessels that feeds your heart, but they have better equipment for it.
Quite a stint- it took a rocket scientist to do it!!!! who-ray for the home team:bangbang::cool::bangbang:
Patting one's self on back always makes for a good day. I enjoyed reading about the man on a mission.
I read a great book on failure analysis (what can I say -I'm a dork engineer) and the author's contention was that necessity isn't the mother of invention - FAILURE is the mother of invention. In your case - the crushed duct.

Great use of available material. It's like the scene from Apollo 13 of all the guys standing around the pile of parts trying to figure out how to get the scrubbers working.
When you get older they might do that same thing to one of the blood vessels that feeds your heart, but they have better equipment for it.

Yeah, charge more too...

I love the words "Free or best offer"... :D:D:wink:

later! OL JR :)