# Pvc bending



## Salvatoreg02 (Feb 26, 2011)

Does anyone know where I can get the bending springs to stick inside the pipe to hold its shape?


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## McClary’s Electrical (Feb 21, 2009)

Salvatoreg02 said:


> Does anyone know where I can get the bending springs to stick inside the pipe to hold its shape?


 
They suck and don't work.


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## wesleydnunder (Mar 19, 2012)

You don't need them. Tape up the ends of the pipe so that they're air tight. As the pipe heats the air inside expands and will not allow the pipe to kink if you don't try to bend too small a radius. I've done this many times on pipe from 3/4" to 4" using a hot box. Not sure a heat gun would work but a hot box does the trick.

Mark


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## running dummy (Mar 19, 2009)

mcclary's electrical said:


> They suck and don't work.


Not what he was asking.



I've heard good things about this company. Worth a try if you are having problems.

http://www.thepipeviper.com/


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## McClary’s Electrical (Feb 21, 2009)

running dummy said:


> Not what he was asking.
> 
> 
> 
> ...


 
They suck and don't work.


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## macmikeman (Jan 23, 2007)

I carry the 3/4 one in my van. Hardly ever use it, but it has been handy once or twice.


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## running dummy (Mar 19, 2009)

mcclary's electrical said:


> They suck and don't work.


Better! :thumbup:


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## 360max (Jun 10, 2011)

running dummy said:


> Better! :thumbup:


 2 identical post
2 lotto thread 
2 b4t thread 

he likes pairs:whistling2:


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## Salvatoreg02 (Feb 26, 2011)

wesleydnunder said:


> You don't need them. Tape up the ends of the pipe so that they're air tight. As the pipe heats the air inside expands and will not allow the pipe to kink if you don't try to bend too small a radius. I've done this many times on pipe from 3/4" to 4" using a hot box. Not sure a heat gun would work but a hot box does the trick.
> 
> Mark


I tape ends. But, seem to always get a little kinking in pipe or flattening of pipe. 
All the work is in PVC so want it to look good.


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## running dummy (Mar 19, 2009)

Dumb question but Ill ask anyway.

Do you wear gloves and form the pipe until it starts to set up before you leave it?


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## walkerj (May 13, 2007)

Salvatoreg02 said:


> I tape ends. But, seem to always get a little kinking in pipe or flattening of pipe.
> All the work is in PVC so want it to look good.


You are not heating it up enough


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## Salvatoreg02 (Feb 26, 2011)

walkerj said:


> You are not heating it up enough


Possibly.


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## chewy (May 9, 2010)

They are all we use over here and we just heat the pvc up with our hands. Exactly like the pipe viper. I have never seen a heat box or blanket here at a supply house or on a site.


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## running dummy (Mar 19, 2009)

chewy said:


> They are all we use over here and we just heat the pvc up with our hands. Exactly like the pipe viper. I have never seen a heat box or blanket here at a supply house or on a site.


I've used a few different ways, a hot box works pretty good but when we are slabbing a "weed burner" works really well. Its just a propane tank with a valve and open flame that you strike to ignite the gas. Not good for exposed work applications but in the slab and where there is no power its hard to beat.


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## freeagnt54 (Aug 6, 2008)

chewy said:


> They are all we use over here and we just heat the pvc up with our hands. Exactly like the pipe viper. I have never seen a heat box or blanket here at a supply house or on a site.


How do you heat up pvc with yours hands?


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## freeagnt54 (Aug 6, 2008)

running dummy said:


> I've used a few different ways, a hot box works pretty good but when we are slabbing a "weed burner" works really well. Its just a propane tank with a valve and open flame that you strike to ignite the gas. Not good for exposed work applications but in the slab and where there is no power its hard to beat.


That's my preferred method. I never run exposed pvc anyway


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## HARRY304E (Sep 15, 2010)

Salvatoreg02 said:


> Does anyone know where I can get the bending springs to stick inside the pipe to hold its shape?


They work good for the small stuff.:thumbsup:

http://www.thepipeviper.com/index.html


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## chewy (May 9, 2010)

freeagnt54 said:


> How do you heat up pvc with yours hands?


Just like your interferring with yourself :laughing:


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## running dummy (Mar 19, 2009)

Huh? I don't think I believe that one. 

Why don't they get you the right tool for the job?


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## electricalperson (Jan 11, 2008)

i usually carry my 2 inch pvc heat box with me in my van. i use that and wont ever buy a spring to bend pipe with. either use that or a blow torch


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## HARRY304E (Sep 15, 2010)

electricalperson said:


> i usually carry my 2 inch pvc heat box with me in my van. i use that and wont ever buy a spring to bend pipe with. either use that or a blow torch


Have you ever tried the spring?

I use it for the small stuff I think it is well worth the money , With a little practice you will be able make all types of bends with it.:thumbsup:


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## chewy (May 9, 2010)

running dummy said:


> Huh? I don't think I believe that one.
> 
> Why don't they get you the right tool for the job?


That is the right tool for the job, I have never seen a new install of EMT here only from the 60's and 70's and only seen Ridgid used once along a carpark wall to feed a card reading machine which they had to do by code so 99% of everything exposed that's not on tray is run in PVC, guys learn how to work with it. I'm not sure we could be convinced by hot boxes and blankets when we do without them now.


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## mnelectrician (Dec 1, 2008)

An EMT bender works on small pipe too. Just have to over bend it.


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## nitro71 (Sep 17, 2009)

If you want PVC to "look good" buy factory bends. Or switch to EMT. I like hot boxes myself.


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## freeagnt54 (Aug 6, 2008)

chewy said:


> That is the right tool for the job, I have never seen a new install of EMT here only from the 60's and 70's and only seen Ridgid used once along a carpark wall to feed a card reading machine which they had to do by code so 99% of everything exposed that's not on tray is run in PVC, guys learn how to work with it. I'm not sure we could be convinced by hot boxes and blankets when we do without them now.


Do you have any pictures?


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## chewy (May 9, 2010)

freeagnt54 said:


> Do you have any pictures?


Of bent PVC? Ill see what I can find at work tommorow.


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## mrmike (Dec 10, 2010)

I've always used a Greenlee heating blanket. I make sure that I don't overheat the pvc. Usually,it takes about 5 min, and i will pick up the piece a few times to see if it will start to flex. Then I take the blanket off & make my bend & use a wet towel to cool it fast & help shape it if needed........


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## BBQ (Nov 16, 2010)

For what it is worth for those who are under the NEC and care to follow it. 



> *
> ARTICLE 352
> Rigid Polyvinyl Chloride Conduit: Type
> PVC
> ...


In my area that is generally interpreted as _'You can't use a common torch' to heat the PVC for bending'._

We can argue about it but it will be the AHJ / Inspectors call to make.

We have blankets, hot boxes for large and small but for site work the guys seem to like the Hotbend http://www.hotbend.com/ it is identified for the purpose ...... fast and needs no power. If we want to use a hot box on large PVC that requires dragging around a 10,000 watt generator.


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## KayJay (Jan 20, 2008)

As far as I can tell, the equipment to help facilitate heat bending PVC that is a made available from manufactures is for convenience and to make installation easier and faster, but not required to be used. You can still easily overheat and damage PVC with blankets and hot boxes and even the torch in the picture above, so using them gives no guarantee of improved quality for field made bends.

Maybe there is some additional info located elsewhere, but I can’t seem to find any listed instructions or reference to requirements for heat bending PVC conduit in the UL white book or on Carlon’s tech info section on their website. NEMA’s guide only seems to reference long radius field bends made in trenches around stakes.

IMO, the heat source and how it is applied is not relevant to NEC 352. To me, that’s like saying you can only cut PVC with a particular type of saw blade or cutter.
Since a heat source is not making the actual bend, and is often not even required to make many field bends in both small and large diameter PVC conduit, I don’t see where the method of applying the heat would be covered under the NEC, unless it where specifically referenced somewhere in the conduit manufacturer’s instructions. 
Only the actual bending of the PVC itself appears to be required to be formed or made with equipment identified for the purpose, such as bending springs, shoes, etc. I guess this means field made wooden bending jigs of the proper radius are no longer acceptable.


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## brian john (Mar 11, 2007)

mcclary's electrical said:


> They suck and don't work.


Answers my questions.


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## cultch (Aug 2, 2011)

pvc glue and a lighter is all ya need


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## wildleg (Apr 12, 2009)

I hate the look of charred pvc - I like the blanket. that heatgun looks nice tho.


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## BBQ (Nov 16, 2010)

KayJay said:


> As far as I can tell, the equipment to help facilitate heat bending PVC that is a made available from manufactures is for convenience and to make installation easier and faster, but not required to be used.


I agree



> You can still easily overheat and damage PVC with blankets and hot boxes and even the torch in the picture above, so using them gives no guarantee of improved quality for field made bends.


I agree





> IMO, the heat source and how it is applied is not relevant to NEC 352.


Here I strongly disagree. 

In your opinion what does "Field bends shall be made only with bending equipment identified for the purpose" mean?



> To me, that’s like saying you can only cut PVC with a particular type of saw blade or cutter.


Yes, it is, and they could do that if they wanted to.

Just like here



> 344.28 Reaming and Threading. All cut ends shall be
> reamed or otherwise finished to remove rough edges. Where
> conduit is threaded in the field, a standard cutting die with a
> 1 in 16 taper (3⁄4 in. taper per foot) shall be used.


They are telling us what kind of die to use.




> Since a heat source is not making the actual bend, and is often not even required to make many field bends in both small and large diameter PVC conduit, I don’t see where the method of applying the heat would be covered under the NEC, unless it where specifically referenced somewhere in the conduit manufacturer’s instructions.



I think as soon as you use a tool to bend PVC that the tool have chosen to use has to be identified for the purpose.

No you don't have to use a heating tool but if you do it has to be the right one. (In my opinion)





> Only the actual bending of the PVC itself appears to be required to be formed or made with equipment identified for the purpose, such as bending springs, shoes, etc. I guess this means field made wooden bending jigs of the proper radius are no longer acceptable.


I find that a very far stretch of the imagination.


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## HARRY304E (Sep 15, 2010)

cultch said:


> pvc glue and a lighter is all ya need


Don't leave the open can open right next to you when doing that otherwise this could happen..











:laughing::laughing:


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## wildleg (Apr 12, 2009)

HARRY304E said:


> Don't leave the open can open right next to you when doing that otherwise this could happen..
> 
> 
> 
> ...


 
it is a little known fact, but a can of pvc glue was actually the cause for the Chernobyl disaster, 3 mile island, and the Fukushima plant disaster. (that and some junction boxes covered in skotchcote)


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## KayJay (Jan 20, 2008)

BBQ said:


> I agree
> 
> Here I strongly disagree.
> 
> In your opinion what does "Field bends shall be made only with bending equipment identified for the purpose" mean?


 
Well, the problem I find with that is within 352 itself. Every time you flex or bow a pvc conduit, like to follow a slight curve of a trench, haven’t you now made a field bend that should be counted toward the total 360-degrees between pull points? I don’t see any exception negating these types of field bends in 352.
Do you use equipment recognized for the purpose when making these types of field bends?

IMO, the source of heat is irrelevant because based on other NEC articles concerning raceways, what matters is the radius of the actual bend while maintaining the internal cross section of the conduit. The type of heat source, as far as I can tell, plays no part in that.

I agree that some things are more appropriate than others for the task at hand, meaning something like a $20.00 propane torch from the hardware store shouldn’t be used to bend 4-inch PVC conduit, but I have to believe that would be self-evident.


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## CanadianBrad (Feb 9, 2012)

I've often wondered about those Pipe Vipers myself. We run kilometers of exposed PVC on the walls at one of our main contracting sites. We have a Greenlee pipe oven, but it's pretty old and doesn't work all that well anymore. I've done everything in the last 6 months(probably 5km worth of pipe) with a heat gun. I take my measurements for the needed bend, and heat up an appropriate length of pipe with the heat gun. Once it flexes fairly freely, I lay it on the concrete floor and form my bend. The floor helps keep the bends from dog-legging, and the cold concrete helps it cool fairly quickly.

I have no complaints running pipe this way. The only thing that we don't bend are 90s, my boss insists on buying cases of factory 90s. I figured those Pipe Vipers would be handy for little bends and that, but I can't imagine getting that thing out after you've bent a 4" offset or a 2" saddle, especially halfway down a 10' length of pipe.

If you pick up one of those Pipe Vipers, let us know how it works.


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## Hairbone (Feb 16, 2011)

take a look at the pvc plugs at cureenttools.com for helping to keep the shape when heating the pipe.


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## jimmy21 (Mar 31, 2012)

nitro71 said:


> If you want PVC to "look good" buy factory bends. Or switch to EMT. I like hot boxes myself.


Personally, I think factory bends look like hell. They put couplings close together right next to the bends. Just screams out amateur hour.

Personally, I prefer a ordinary weed burner torch. I've used every method imaginable and I think the torch works best. The code article is to protect craftsmanship. I know some guys that can't use a torch without burning the hell out of it. They shouldn't be using a torch. My bends look perfect and I have no problem putting them in exposed. If I didn't tell you, you would never be able to tell it was bent with a torch.


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## freeagnt54 (Aug 6, 2008)

chewy said:


> Of bent PVC? Ill see what I can find at work tommorow.


I'd like to see a rack of exposed pvc. I imagine it looks like crap


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## freeagnt54 (Aug 6, 2008)

jimmy21 said:


> Personally, I think factory bends look like hell.  They put couplings close together right next to the bends. Just screams out amateur hour.
> 
> Personally, I prefer a ordinary weed burner torch. I've used every method imaginable and I think the torch works best. The code article is to protect craftsmanship. I know some guys that can't use a torch without burning the hell out of it. They shouldn't be using a torch. My bends look perfect and I have no problem putting them in exposed. If I didn't tell you, you would never be able to tell it was bent with a torch.


Yeah those factory bends are crap, I don't even like putting them in the ground let alone exposed


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## sseivard (Apr 25, 2012)

The only thing worse would be the 4" female adaptors.


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## Amish Electrician (Jan 2, 2010)

I'm not impressed with the "Pipe Viper" as a bending tool, but I might get some to protect the form of pipe as it is bent.

The problem with most heating methods is that they apply heat to too small a 'spot' on the pipe. That leads to burns, kinks, and flat spots.


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## sbrn33 (Mar 15, 2007)

The springs work ok for a small kick in a trench where it will be hidden but some of the time you can just force it then.
The springs make some ugly freaking bends, so if you have any pride in your work try to switch to EMT or GRC.


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## coon88 (Dec 9, 2011)

Just stick it on the tail pipe of the truck bubba and giver a little gas


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## Aegis (Mar 18, 2011)

wesleydnunder said:


> You don't need them. Tape up the ends of the pipe so that they're air tight. As the pipe heats the air inside expands and will not allow the pipe to kink if you don't try to bend too small a radius. I've done this many times on pipe from 3/4" to 4" using a hot box. Not sure a heat gun would work but a hot box does the trick.
> 
> Mark


This is good for upsizing pipe as well


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## ecelectric (Mar 27, 2009)

I've used the spring to keep the pipe round after I put it in the hotbox and am trying to do my bend . Works great for that , but I would never use the spring alone by it self


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## cory3408 (Aug 12, 2012)

Heat gun, wet rag, gloves, an patience is all it takes to make a good looking pvc raceway. 

Factory elbows look bad. 

As long as the inner diameter isn't effectively reduced and the installation is neat and workmanlike (they go together), I can't imagine any AHJ giving an installer a hard time using an unidentified means of heating the stick. 

Some customers want exposed pvc (over thinwall) to save a few bucks on supply costs. I leave it up to them.


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## dubya774 (Aug 14, 2012)

Cory, how many electrical installations have you completed? Are you a JW, or a small work installer? I think tennessee is one of the states that allows anyone to apply for a liscense without going through a proper apprenticeship program. Saw some of your recent posts, just wondering...


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## chewy (May 9, 2010)

I think factory 90s on PVC look tidier then having connections between sticks at random intervals on exposed stuff.


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## cory3408 (Aug 12, 2012)

Glad you asked dubya.

Pretty new as far a residential/ commercial installations (<6 mos exp). My experience is in industrial environments (~5 yrs, G9). 

I took my trade exam to become a "Limited Licensed Electrician." Not all TN jurisdictions accept this license, but most do. There is no apprenticeship required. 

It limits me to jobs <25k, and I am not allowed to advertise as a contractor. I am still employed at an industrial facility- I want to do some smaller jobs on the side so this license really fits. 

The next level above me would be a CE license, which is a full electrical contractor license accepted in all TN municipalities (no monetary limit). I would have to pass a business exam and get full bonding to do this-- doesn't benfit me at this time. Just want to learn and make some $ (legally).


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