A cabling crew was installing conduit for FIOS at my house this week and they needed to put a little offset in the conduit. The guy stuck the end of a piece of 1″ PVC conduit into the exhaust pipe of their diesel compressor for a minute or so, just long enough to soften it. Then he made a little S-bend and held it til it cooled.
Pretty slick trick, I thought. He said it would work with the exhaust of a pickup also.
In certain scenarios, flat roofs make more sense than pitched roofs (and vice versa).
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Replies
Yep, where they expect to do a lot of it sparkies use a sort of cylindrical electric oven that you stick the pipe into for a minute or so.
DanH,Saw one idiot pour pvc glue on conduit and light it. Also go some on his pants leg and was rolling around in the trench to put it out.Bent the pipe though.KK
Saw one idiot pour pvc glue on conduit and light it. Also go some on his pants leg and was rolling around in the trench to put it out.
Bent the pipe though.
Video, we want to see the video of that!!
And if no video exists, ask'em if he can do it again.
Saw one idiot pour pvc glue on conduit and light it. Also go some on his pants leg and was rolling around in the trench to put it out.
I suppose his last words prior to ignition were something like, 'Hey, Bubba! Watch me bend dis pipe!'
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Very common trick but a hint.
Have a cold coupling handy and shove it over the end of the pipe as soon as it comes off the heat so you hold the round shape, then do your bend. This way you can pull it off and get whatever fitting you need on there when you install it. If nothing else, you know that coupling will fit ;-)
Illegal here and the inspectors will bust you for it and make you uncover and tear out any underground conduit heated that way. .
Funny story about doing that though...
One excavator always heated his bends up on his backoe exhaust. He had been warned repeatedly by inspectors about the practice. One day an inspector drove by and spotted the guy with a pvc pipe stuck up in the air off his exhaust out back of a house so the inspector pulled up in front of the place.
Inspector was spotted by the contractor who raced out front to dissuade the inspector from checking things out... which was exactly what the inspector hoped the contractor would do. Inspector just kept talking and hanging around until he could smell the pipe burning, then politely smiled and left .
Contractor frantically raced out to his his back hoe which by now had melted PVC down the exhaust, over the muffler and onto the engine.
Great story!"Illegal here and the inspectors will bust you for it and make you uncover and tear out any underground conduit heated that way. ."Because it was heated in the exhaust pipe?
Because it was heated and bent at all?What's the reasoning?BruceT
Local PUD has determined that it violates the UL listings for the pipe as well as it has the potential for deforming and weakening it which then can cause problems when pulling the feeder cables through site bent pipes. They insist on factory made bends.I believe it has to do with the lack of temperature regulation.
I have seen some that the bends were so misshapen that it was a miracle anyone got any cable through it.
Life is Good
But I watched the guys at our building install a major power conduit array underground, using a torch setup so bend the pipes. This was big commercial job, heavily inspected. And the local inspectors are pretty tough by midwest standards.And bending avoids joints, and joints add potential for leaks and cable hangups.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
IIRC the concern is bending to the point where the circular cross-section, and therefore the space available for conductor fill, is compromised. I think I've seen this done on larger conduit where the pieces were filled with sand in advance of heating in order to prevent this.
Jeff
Certainly. And the degree to which the cross-section is compromised depends on the technique used and the skill of the user, along with the severity of the angle. Not one hard-and-fast rule.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
we use special pipe plugs, they keep the air trapped inside and the pipe can't collapse while you bend it, ideal for larger pipe, you could bend 180º if the pipe was hot enough, even though sheperds hooks in PVC is a really dumb idea.
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"we use special pipe plugs, they keep the air trapped inside and the pipe can't collapse while you bend it..."Any ballooning as the air expands in the softened zone?
BruceT
I've never seen that, even in the cold when we overheat lots of the stuff the plugs will usually pop off and the walls flatten out or kink, before we get a chance to set the bend
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It is only here in this small PUD that the inspectors are so stringent on the exhaust bent PVC conduit, outside of this small PUD area the publicly traded power company allows some bending of the conduit .
Maybe the wall cross section gets thinned out to much from the bending? I don't know the answer for certain , just know that the rule has been in effect here for years and is stringently enforced.
Life is Good
This is the code section
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.You can see the words "bending equipment identified for the purpose." so they have the power to reject "tail pipe bends" no matter how pretty they are.
a 8' baseboard heater layed flat with a piece of expanded metal works great too. It tends to leave a few grill marks, but it works great.
If you put this unit in a 10"x8' metal duct pipe, it make a great bender for pvc trim and pvc mouldings.