Bending PVC

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mgookin

mgookin

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Location
Fort Myers, FL
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Retired inspector, plans examiner & building official
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".
They only need to be long enough to accomplish the offset. I'm guessing that's around 8-12" long???
I'm thinking toaster oven. If it works I can get a few ovens.
Reading online if you uniformly heat the pipe to 225-275F it will be at optimal condition for bending and not distorting as it cools.

Anyone think I'm overlooking something?

Unless anyone knows where I can get them cheap?
 
I caught my Dad trying to bend PVC with a torch. He was scorching the carp out of it. I got out the heat gun and that works really well, although not super fast.
 
Well I ran to the store to get a toaster oven, and came back with a $6.88 toaster!

I think I can make some 8" sticks, load them from the top and warm them up.

Time for a little experiment.
 
mgookin said:
Well I ran to the store to get a toaster oven, and came back with a $6.88 toaster!

I think I can make some 8" sticks, load them from the top and warm them up.

Time for a little experiment.
Click to expand...

Since toasters heat mostly by radiation, you may find that it is hard to get the interior of the pipe section hot enough before you char the outside surface.
Have you tried a microwave? Use a low power setting to allow the temp to equalize as you are heating.

PS:
"The recipe for perfect toast
is easy to express.
Toast it till it burns, and then--
twenty seconds less."
--Piet Hein
 
I had to make a bunch of 4" offset at the end on 3/4 pvc to get out of the walls of a school. I needed like 300 offsets all in all.

Greenlee hot box and a simple jig made from a 2x6 and some nails.

Just get your first offset built and lay it on the board, then drive some nails where you need them.

Next time just drop the hot pipe right in the jig you just made and push down on it a bit at the bends to keep it round.

Cool it quick with a wet rag.

A heat gun or whatever is good for one or two pipes here and there.
 
Well the toaster is really quick. And it didn't take long to find that "20 seconds less point"; it was right before the smoke.

It got it plenty deformable and it remained that way for quite longer than expected.

I just need to make the jig now. I drew it out. I'll head over to my buddy's wood shop tomorrow and make one for now. Once I see that work I'll have him make a jig that holds 10 or so. I can get more than 10 in the toaster.

Since it's 3/4 pipe with an OD of .84" the jig can be made out of plywood cut on a bandsaw. It's depth only needs to be as much as the radius (0.42")
I'm going with 4" radius for the bends. Here's the drawing scaled 1:1
 

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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.
 
Jraef said:
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.
Click to expand...

We would fire that guy first day, way too slow.



And a note to all, the NEC requires a tool identified for the purpose to field bend PVC.
 
I would try to use a large pot of boiling water over a propane burner to heat many short pieces at once and then make a jig that can handle multiple offsets at once.

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.
 
tkb said:
I would try to use a large pot of boiling water over a propane burner to heat many short pieces at once and then make a jig that can handle multiple offsets at once.

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.
Click to expand...
I would not recommend the next step of going to boiling oil.
 
mgookin said:
Here's the drawing scaled 1:1
Click to expand...
Something looks slightly off about that drawing. Did you make it by drawing one edge, and then just duplicate the curve left or right 0.84" to get the other edge? That will cause the resulting shape to be narrower in cross section in the curves.

Instead, you'd need to draw the outside edge of each curve at a radius of 4.84", concentric with the inside edge at a 4" radius.

My apologies if that is what you did, it just doesn't look like it to me.

Cheers, Wayne
 
GoldDigger said:
Sorry, but I have publicly declared that to be my sarcasm font, so you can tell now and in the future.
Click to expand...

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.
 
mgookin said:
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".
They only need to be long enough to accomplish the offset. I'm guessing that's around 8-12" long???
I'm thinking toaster oven. If it works I can get a few ovens.
Reading online if you uniformly heat the pipe to 225-275F it will be at optimal condition for bending and not distorting as it cools.

Anyone think I'm overlooking something?

Unless anyone knows where I can get them cheap?
Click to expand...


http://www.amazon.com/Thomas-Betts-E994DR-CTN-2-Inch-Conduit/dp/B00IOX3VJM

Cant tell what offset they have tho.
 
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