Bending PVC

[GoldDigger]

GD just an FYI when I look at the previous posts I don't see any difference in font. :happyno: I see a reduction in text size but not comic sans.

I think this has to do with how each browser displays the forum and people's preference settings.

Good point.
If you are viewing on a Linux system you will not have Comic Sans by default and a different font that looks smaller will be substituted.
You can download the free Microsoft Core Fonts package to get it, as I did.
(Origin story: it was developed to be the speech balloon font for "Bob" the helper. It was not ready in time and was not used for that purpose.)

 

[iwire]

Good point.
If you are viewing on a Linux system you will not have Comic Sans by default and a different font that looks smaller will be substituted.
You can download the free Microsoft Core Fonts package to get it, as I did.
(Origin story: it was developed to be the speech balloon font for "Bob" the helper. It was not ready in time and was not used for that purpose.)

I don't run Linux, tonight I am on an old IPad.

Another oddity is if you choose to type your text in say "MS Word" then copy and paste to the forum the text sizes often get huge and makes you seem like your shouting.

 

[Sparkdoctor]

We've used many different methods to bend PVC, i.e. heat blankets, torch, box heater, truck exhaust, etc. It usually depends on the scenario to which works best. In your situation I believe I would build a jig that would accept the entire 10' length of pipe, heat the stick in a box heater and after it has cooled in the jig grab a pair of PVC cutters and clip them off then. IMO this would be quicker than trying to heat and bend the individual pieces.

 

[iwire]

I think worth considering.

ARTICLE 352 Rigid Polyvinyl Chloride Conduit: Type PVC



352.24 Bends — How Made. Bends shall be so made that the conduit will not be damaged and the internal diameter of the conduit will not be effectively reduced. Field bends shall be made only with bending equipment identified for the purpose. The radius of the curve to the centerline of such bends shall not be less than shown in Table 2, Chapter 9

 

[mgookin]

Put some sand in a throw-away aluminum pan and heat it up to 450 degrees in the oven. Use a funnel to pour it into the PVC pipe, (having plugged or taped up one end). After a few minutes the pipe will get soft and you can bend it, the sand keeps it from collapsing and heats it evenly from the inside.

This guy did a video on it for making walkway lights, using a torch instead of an oven, but it's the same concept.
https://www.youtube.com/watch?v=FLM...JZep-jST4&annotation_id=annotation_1198886763

Use the toaster for making tasty toast.

I watched that video. I was more impressed with his lights than his method. Heating up that sand would be too slow. And our place is too clean for that operation.

With the toaster I can set the dial to the proper time and run a dozen or more at a time, and that's with just a single 2-slice toaster.

 

[mgookin]

Well here it is. I am amazed at how fast this is. That was about 20 seconds in the toaster.
Now I need a dunk tank to cool it in a timely fashion.

 

[K8MHZ]

And a note to all, the NEC requires a tool identified for the purpose to field bend PVC.

We have been down this road before.

What is the definition of 'identified for the purpose'?

The short answer is recognizable as suitable for the purpose. Per the NEC.

No labels or listings needed.

 

[iwire]

We have been down this road before.

What is the definition of 'identified for the purpose'?

Yes and nothing has changed

The section says what it says, it was placed in their for a reason and it is entirely up to the AHJ to decide which tools are identified for the purpose

If you try to claim a toaster or a exhaust pipe is identified for the purpose of bending PVC I will LMAO.

 

[kwired]

I need to make 1/2 pvc offsets in production run lots of 100 to 1,000 pcs per run.
The offset is 1.5".

You seem to be needing a large enough quantity that it may be well worth asking the companies that make fittings if they can make what you want for you. They probably have cheaper labor then you do, but how soon do you need it vs how soon can they get them to you also needs considered.

 

[K8MHZ]

Yes and nothing has changed

The section says what it says, it was placed in their for a reason and it is entirely up to the AHJ to decide which tools are identified for the purpose

If you try to claim a toaster or a exhaust pipe is identified for the purpose of bending PVC I will LMAO.

It's a new toaster and it is setting on a jig that looks like it makes perfect bends. It's obvious that the new toaster was purchased to be used for the specific purpose of heating PVC (not bending) and it's been shown to be able to do that without damaging the PVC. To me, the set up is very recognizable for the purpose.

Now, if the toaster was full of crumbs and just grabbed off the counter, that would be different.

If you were an inspector would you gig mgookin on his methods if the parts turned out fine? I sure wouldn't. Now, if the parts were damaged, that's a no brainer.

If the NEC wanted listed tools to be used, it would say so.

 

[Jraef]

After you make and install an offset like that, how would the AHJ know how it became an offset? Sure, if the toaster and jig was right there next to it, but otherwise?

 

[iwire]

It's a new toaster and it is setting on a jig that looks like it makes perfect bends. It's obvious that the new toaster was purchased to be used for the specific purpose of heating PVC (not bending) and it's been shown to be able to do that without damaging the PVC. To me, the set up is very recognizable for the purpose.

Now, if the toaster was full of crumbs and just grabbed off the counter, that would be different.

.

LMAO, really.

Again not up to you unless you are the AHJ.

If you were an inspector would you gig mgookin on his methods if the parts turned out fine? I sure wouldn't. Now, if the parts were damaged, that's a no brainer.

Again in my opinion it is up to the AHJ and if I was the AHJ and saw someone bending PVC with a toaster I would tell them to stop doing so.

If the NEC wanted listed tools to be used, it would say so

No one has claimed they have to be listed. They have to be identified for the purpose.

Such as:

A PVC heating blanket

A PVC pipe viper

A PVC hot box

A PVC hot shot


A toaster is in no way identified for the purpose.



Now all that said in the interest of full disclosure another of the mods feels that section is not talking about the heating of the product only the tools that physically bend the PVC.

As much respect I have for that mod I disagree with them about that.

 

[K8MHZ]

After you make and install an offset like that, how would the AHJ know how it became an offset? Sure, if the toaster and jig was right there next to it, but otherwise?

Just put a label on the toaster.

PVC CONDUIT HEATER - NOT FOR FOOD USE

And one on the jig:

PVC BENDING JIG - ALSO NOT FOR FOOD USE

 

[tkb]

If the bends are done at the shop, they are not field bends so 352.24 doesn't apply.
Also the act of heating is not the same as the act of bending. They are two separate activities.

 

[iwire]

After you make and install an offset like that, how would the AHJ know how it became an offset? Sure, if the toaster and jig was right there next to it, but otherwise?

There is never any difficulty in choosing to ignore the code.

 

[iwire]

If the bends are done at the shop, they are not field bends so 352.24 doesn't apply.

:roll:

BS

 

[iwire]

Let me spin this around and ask a question

What does the code section mean if we can use any method we want?

 

[mgookin]

Yes and nothing has changed

The section says what it says, it was placed in their for a reason and it is entirely up to the AHJ to decide which tools are identified for the purpose

If you try to claim a toaster or a exhaust pipe is identified for the purpose of bending PVC I will LMAO.

Thanks for pointing that out gentlemen.

I just read Art 352 and also Ch9 T2.

We'll see what our NRTL inspector says about it next time he comes. He's pretty chill so I don't see a problem. Although we are not field bending, we prefer to be irrefutably in compliance with all NEC requirements so EC's don't face any challenges in the field.

I will grab a bender from the supply house next time I'm there. We'll use the jigs for a cooling station to hold the form while it cools. I have a slight adjustment to make to the design (a straight run between the two bends) and then I'll greenlight the woodshop to make us a jig that holds 10 pcs.

As to the toaster, I had a call this morning from a local EC who saw this thread and offered up his pvc ovens which are collecting dust. If NRTL inspector says that's what we need, we'll go that route.

I needed to make one for a proof of concept and it worked. Total cost $6.88!

Thank you again. This forum is an invaluable resource.

 

[ADub]

Is someone really using a toaster to heat pvc??? Oh my lol


Sent from my iPhone using Tapatalk

 

[TommyO]

Im not sure if the boiling water would heat the PVC enough, but I would give it a try if you want to get a production line going.

I've used boiling water (with fair amount of salt to increase by a few more degrees).

It's hot enough that PVC will return to what it remembers as it's shape (ie. unbend itself)
And it is bendable (but not as pliable as you can get PVC to be)

Doing a jig like this I think it'd probably work fine. But because of the water evaporating off it when you pull it out, it cools rapidly and gets rigid fairly quickly.
Having a jig like this would probably be ideal so that you can put it in place quickly.