How to straighten PEX

[Joelk]

I want to install some PEX that has been in a roll for a long time. It wants to return to curved shape even if I bend it back against the curve.

I am planning to push the PEX into some 3" PCV pipe and leave it overnight to see if that straightens it out, but was wondering how other people have straightened PEX.

It is cold outside so laying it out in the Sun is not an option right now.

What techniques have you used to straighten PEX?

 

[moserjj]

I watched my plumber dangle it in front of a portable kerosene heater. Seemed to work good and didn't take much heat to the pipe

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[kkroger]

Heat Gun or Hair Dryer should do it... or a Propane or Kero heater as stated... I unrolled it and straightened it by hand... never a problem but if it has been hot and cold while in the roll it could present a bit of resistance....

 

[NC357]

Yeah, it MUST be heated. It will never happen without heat. You could also try to rig up a way to run hot water through it....

 

[Streetbu]

Hot water does it quick and easy....

 

[Joelk]

I put two pieces of 3/4 PEX in 2" PCV overnight.

I pulled them out and they were significantly straighter than when they went in.

I left one out and it rebent a good bit, but was still straighter than prior.

I ran hot water through the other while still in PCV and then pulled out after a few minutes.

It also rebent, but perhaps slightly less than the one that did not have hot water run through it.

 

[gayler]

I tossed a couple 100ft rolls in my hot tub. Maybe in the bathtub.

 

[Joelk]

I have read that PEX should not be subjected to high temperature.

How much heat can it safely tolerate?

 

[Streetbu]

Well my boiler is set to 185 degree's so that temp is safe.... I have PEX runs to all of my baseboards

 

[beelsr]

all PEX I've ever seen has a temp/pressure rating printed on it.

my baseboard runs at 180 or 190, too. Wear gloves...

 

[Joelk]

I know it handles hot water, but some suggested heater/heat gun. How much of that type of heat will it handle?

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[mrolds88]

Last PEX I worked with, I unrolled in the sun.

 

[NC357]

I know it handles hot water, but some suggested heater/heat gun. How much of that type of heat will it handle?

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If you see it start to melt that's too hot. Otherwise it's fine.

 

[myredracer]

I thought PEX pipe has a coil memory? PEX-b has a much greater coil memory than PEX-a and I think PEX-b is what is usually sold in retail stores because it is cheaper to manufacture. You can straighten a coil somewhat to install it but will return to it's original form. That is why they sell long sticks of it alongside the coils.

 

[Capt Chrysler]

Original form will be straight. As it is an extruded tube. Then rolled after it passes the cooling area.

Capt. Chrysler