Instructables

Step 10: Bending

WARNING: Before you decide to bend PVC pipe, please consult the ‘Cautions’ section of this Instructable. Bending PVC pipe involves heating the pipe close to its melting point, which can cause the PVC to out-gas chlorine and dioxins. These chemicals can cause harm to the human body over long periods of exposure. Perform the heating of PVC outdoors or in a well ventilated area such as a garage with the door(s) open. If you have to do it in a basement or other interior room, use a respirator or a fan with an open window.

To bend PVC pipe you will need a few supplies. The first is a PVC Bending Jig, whichI have uploaded plans for, located here for SketchUp. This jig will allow you to bend PVC controllably and easily. The trick of bending PVC is that your bend may not end up exactly where you want it in the overall position of the pipe length, so it is suggested that you bend the pipe FIRST, and then cut it to length.

To bend PVC pipe you need:

-  PVC Bending Jig (free plans available here)
-  PVC pipe
-  Heat Gun or Propane Torch
-  Sand or Cat Litter
 PVC End Caps or Duct Tape

1.  Place duct tape over one end of the PVC pipe segment to be bent. This will allow you to fill the PVC pipe with filler.

2.  Pour sand or cat litter into the opposite end, filling the entire PVC pipe to be bent with the filler.  Shake to distribute and top off if necessary.  You’ll need to fill the entire pipe.

3.  Place an additional duct tape over the remaining opened end of the PVC pipe segment.

4.  Heat up the PVC pipe with a heat gun or propane torch along the area to be bent.  Apply heat until the area appears pliable. Don’t overdo it, or you will deform the PVC.

5.  Once the desired softness of the PVC pipe is achieved, place the softened area into the joint position on the PVC bending jig.

6.  
Using the force of your hand, move the top part of the jig to the desired angle and hold in this position for about a minute or until you think it has cooled.  You can use the holes in the jig to hold the peice in place.  Make sure it is completely cool before removing from the jig.

7.  Perform the cuts on each end of the newly curved pipe as needed.

 
 
Remove these adsRemove these ads by Signing Up
Bri_Aday7 months ago

You can also form PVC using boiling water. I find it is easier to control the heat.

An extra step for your instructable.

I remember discussing this somewhere else on instructables but can't really remember so I'm just gonna give you the link to the site that promotes it.

www.thepipeviper.com/

It's a site that sells a tool with which you can cold bend a pvc pipe.

I live in Belgium (Europe) and followed industrial science in highschool. We had electricity there which involved alot of pvc bending. I however never heard off hot bending pvc before I came to this site.

We always bended our pvc cold using the same tool that that company sells. It doesn't damage the pipe and keeps the hole inside open as much as it would if you didn't bend it. It's really handy, easy and there is no danger at all of hurting yourself. And it doesn't take more then a 15 year old boys strength to do it :)

So check it out I'm sure you'll find it interesting :)

Michel
I looked at the site you linked. Very interesting tool. They don't have a FAQ page, so I thought I'd ask you, since you have experience:

Is this suitable only for conduit applications, or can it be used for household water systems? I'd think that even though the pipe is 'not damaged' by cold bending, it may be weakened enough that it would not reliably carry pressurized water for household cold and hot water. So, is this used for water, or only for conduit?
I remember the plumbing classes in my highschool using the same cold bending method I described above for your usual kitched plumbing. You are right that the structure is weakend but the same goes for hot bending (in both cases you are stretching out the material over a longer length)

So yes you can use it to run hot and cold water unless you plan to do some crazy bending with it (over 270 degrees) but for normal 90 degree bends it should do fine :)

Wow. Thanks for the quick reply and information. I may stick with solvent-welding to molded fittings for plumbing, but I have some ideas for running conduit for which this might be just the ticket.

I will have to see if a regular length of flexible spring will work almost as well.
TheGreatS3 years ago
I hear filling the PVC pipe with hot sand also is a method for bending the pipe.
kminer49er4 years ago
One of the problems that you may encounter when using PVC in unsupported lengths of over 4 or 5 feet, is sagging.  This can be easily remedied by running a piece of thin-wall electrical conduit (EMT) inside the PVC.  For 3/4" pipe, use 1/2" EMT; for 1" PVC, use 3/4" EMT and it should run the entire unsupported length.  This will give extra rigidity to both vertical or horizontal runs (of up to 10')  It is reasonably cheap and only adds a small amount of weight.
Grimmster4 years ago

An even easier way to bend PVC is sticking it in boiling water.  If you cut it in half down the length of the pipe first, you can easily make strips to cover your PVC chairs, tables, etc.