uncrimp snao lock pipe?

[Reggie Burnett]

Hey guys

You guys have been so helpful with some of my other posts. Thank you! I'm zeroing in on my strategy.

One question -- the start collar and wyes that I buy at my local big box store have the crimps going the wrong direction. They are for HVAC and not dust collection. I know that I can buy a crimp tool to crimp and uncrimped end. The hard part is how to "uncrimp" a crimped end.

Do you guys have a tool/strategy for that? Do you actually uncrimp it or use a connector to reverse the crimp direction?

Thanks!

[Jamie Buxton]

Strategy: don't worry about it.

[Jim Becker]

Easiest way is to get something hard and round that you can slip into the crimped and and then use a hammer to un-crimp the crimps, as it were. It will not be perfect, but it's doable. But it's important to do this because of the flow direction as you have noticed.

[Frank Pratt]

I would estimate that having the crimps backward to the airflow matters exactly not at all. I have a few places where the crimps are backward & they haven't been any issues.

[Jim Becker]

I would estimate that having the crimps backward to the airflow matters exactly not at all. I have a few places where the crimps are backward & they haven't been any issues.
It could matter a lot for certain machines and operations, such as the planer with stringy shavings getting caught on the crimps facing opposite of air flow. I agree that for fine dust it will not be much of a concern. But there's zero problem with doing the work to getting things facing the correct way if the OP wants to...

[Bill Dufour]

That is what the horn on an anvil is for. If you do not have an anvil grab the biggest piece of iron pipe you can in your vice. Any fence posts around with the correct diameter.
Bill D

[Frank Pratt]

It could matter a lot for certain machines and operations, such as the planer with stringy shavings getting caught on the crimps facing opposite of air flow. I agree that for fine dust it will not be much of a concern. But there's zero problem with doing the work to getting things facing the correct way if the OP wants to...

I agree with getting the crimps the right way if it's convenient, but I certainly wouldn't loose any sleep over it. I've never had planer shavings clog things up. Screws would tend to catch them worse than a backward crimp & I've never had issues with either.

[Jim Andrew]

I have a general purpose vise bolted to a bench top. It has a flat area behind the vise for the purpose of providing an anvil type surface. I hammer my crimps out on that. You also need a hand crimp tool to put them in the other end. I picked one up at Menards.

[Ben Helmich]

Not knowing anything at all about metal ducting.....can you just cut the crimp off ?

[Frank Pratt]

Not knowing anything at all about metal ducting.....can you just cut the crimp off ?

The concern is with the crimps on the fittings. You can't cut them off & you can't turn the fitting around the other way.

[Jim Becker]

The concern is with the crimps on the fittings. You can't cut them off & you can't turn the fitting around the other way.

This is true...there's not enough metal left if the factory crimp is cut off. So flattening them and recrimping opposite is the method. This whole process only takes a few minutes at most for a wye. It's not complicated and the metal isn't so thick that it makes the job difficult. And a crimp tool is inexpensive to set things up correctly after that.

[Thomas Crawford]

Order some off the internet without the crimps. Shipping and cost isn't too bad if its just a few fittings.

[Rick Potter]

I did my whole system using spiral pipe from the local HVAC supplier, which had one crimped end, along with the fittings with crimps.

Like Bill said, I got a piece of 2" steel pipe (larger would have been better), put it in a vise, and used a hammer to tap out the crimps on the fittings, then used a crimper from HD to recrimp the other side. I guess I am slow,my fittings took about half an hour to do each to the point where I was happy with them (bad rotator cuffs).

One improvement would have been to use a cheap air hammer with a flat hammer bit, but I could not find one. I also got the bright idea to use a palm nailer with a steel shaft. It worked great, but ruined the palm nailer after a couple fittings.

EDIT: I would like to add a tip....Do not seal the fittings with duct tape, it will start to deteriorate on you. Use the aluminum tape that HVAC suppliers sell. It seals great and is easy to use. Mine has been up for about 10 years and the tape looks like new. It is also a lot easier to remove if necessary. I used aluminum pop rivets to fasten the system, along with the aluminum tape for sealing.