bending PVC pipeing...

[Everfalling]

i was thingking of doing away with the standard up and down Res made from a clear 2.5" in diameter PVC pipe and making something a little more curvey and wild. is it possible to warp and band the pipe without creating a kink where you bend it? let's say i wanna make a clean looking L bend. anyone know how i should go about doing that w/o the innerpart of the bend caving inward (like when you bend a straw at an angle)? i'm thinking i gotta heat the plastic uniformly, but i donno if the outer part of the bend will expant fast enough to keep its shape... what do you think? has this already been done?

 

[agent420]

I think it would be tricky to get a full 90', the outside edge would have to stretch quite a bit and the result would be a thin wall.

Anyway, take a look here, they discuss bending methods for clear pvc.

Seems to be very similar to the methods used to bend glass.

 

[sn3ak3rp1mp]

In addition, you mentioned clear piping. I assume that you want this to come out looking cool. Heating the pipe without discoloring it gives you more challenges.

I hope someone around here has some experience or can point you in the right direction. If you pull this off, promise to post pics and howtos!

 

[Wild Weasel]

Electricians heat the pipe up and bend it to 90 degrees on a special heating table...but I suppose you would slap together some stationary points to hold the PVC pipe, and then slowly cook the corner with a blow torch and bend it by hand.

But that brings up the bubbles and toxic smoke if done in a rush job...

Good luck!

 

[Susquehannock]

How about some clear PVC fittings instead?

http://www.usplastic.com/catalog/category.asp?catalog_name=USPlastic&category_name=54&Page=1

 

[Logan321]

Yup, with a heatgun, a form of some sort (just a curved corner on a piece of 3/4" plywood would do fine), patience and constant motion of the heatgun, you should be able to make nice bends in PVC. You might want to get some extra so you have some to practice on, and don't expect to make clean bends smaller than 6x the diameter of the pipe (ie, 1/2" OD pipe, 3" minimum inner radius)

 

[Tech-Daddy]

I have not clicked the above link, so I am not sure if this has been covered... fill the pipe with sand to give it internal support during the bending process. This will minimize the kinking...

hth!

 

[Nivram]

Yeah, remember that when you're bending any pipe, you're compressing the inside of the curve, and stretching the material on the outside of the curve. That can, if you're not careful, make it very thin in spots, or even break through the material. I would definitely recommend making your bend(s) slowly and carefully, using as even of heat as possible (and don't be surprised if you have to do it more than once!).

As far as pvc electrical conduit, I have seen that bent into 90 degree bends using nothing but a propane torch to heat it. That was probably 2" diameter conduit, and they took a lot of care doing it. For bending copper tubing, I've seen bending tools that looked like nothing more than a 12" long spring, to help prevent kinking. I'm not sure what size material you're thinking of bending, but it might be worth looking into something like that, and then using an oven to heat your material.

Remember, too, to protect your hands from extra-hot pvc material!!

 

[synaps3]

Yeah, it would be bad to get melted plastic on your hands. It does not come off easily, and it BURNS bad...

I would not bend PVC; there are so many fittings that it seems almost silly to have to bend it. I understand that bent PVC would look good, but I know for a fact the PVC I used to use for cannons will burn if you are not careful. So I would not use a direct flame, use a heat gun. Don't make sharp bends, but instead, make them very gradual, big bends. Good luck, you will need it.

 

[Everfalling]

i'm thinking of ultimatly doing a wider curve. i just used a 90 degree bend as an example of what i thought was going to happen to the pipe in general. i think if i make a form, and the bends arent too sharp, i think i might be able to pull it off


as for the sand idea, wouldn't you end up getting bits of sand stuck within the pipe after you soften it with a heat gun and then bend it?

edit: how much does a basic heat gun go for?

 

[Susquehannock]

Not sure of the quality, you can get 1,500w heat guns for $10 ~ eBay

Hmmm, I was wondering about sand sticking to the tubing too.
Using sand/glass beads is an old motorhead trick for bending fuel & brake lines.

 

[bigbadgreen]

yes the sand trick is probably better suited to metal pipes where there isn't anything melting. A better method would be to use a very flexible spring the same diameter or slightly smaller than the inside of the pipe. This will allow for a nice even curve. If you can, use a heat gun and clamp one end of the pipe down on a workbench, with one board one the thoutside and one board on the inside atleast as tall as the pipe. clamp the inside board before the spot you want the bend to be. Two people would be preffered as this will help keep the heat even with one on the heat gun and one bending the pipe. Use very slow deliberate pressure and expect to mess up the first few times.

 

[Logan321]

The reason why I said plywood is cause that's what I used to bend PVC with a heatgun in my electrical entry level training course... Not clear, mind you, but I'm sure it'd be the same procedure. Though just about anything that's round on the outside would work just as well, most likely... like a glass jar or tin can.

Just start heating at the beginning of the bend, and work the gun back and forth, and put light pressure on the pipe to start the bend. Keep a damp cloth handy to cool the pipe once you've got the bend you want.