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i know you can bend PVC pipe by heating, but...

Posted: Mon Oct 01, 2007 5:42 pm
by JDP12
I have a need to heat and bend a section of PVC with an endcap on it, will the endcap also bend?

I need to form it all into an ovalish shape... would the endcap also bend/ conform to the shape i need?

oh by the way, this is for a fishing bait box sort of thing

Posted: Mon Oct 01, 2007 6:23 pm
by Marco321
Hey
Yeah, as long as its pvc it will bend, it just might take a bit longer to reach that temp. Just be careful to do it in a well ventilated area, if pvc burns it will release harmful dioxins, and the PVC cement may not like being heated or may release toxic fumes.

Posted: Mon Oct 01, 2007 6:26 pm
by Pilgrimman
I'd bend it with hot water, not a flame.

Posted: Mon Oct 01, 2007 6:48 pm
by Lentamentalisk
Marco321 wrote:Just be careful to do it in a well ventilated area, if pvc burns it will release harmful dioxins, and the PVC cement may not like being heated or may release toxic fumes.
not just if it burns, heating it up at all will release fumes that will give you cancer... either do it in an incredibly well ventilated area, or wear a gas mask. no mater what DO NOT do it indoors!

Posted: Mon Oct 01, 2007 7:27 pm
by clide
Lentamentalisk wrote:not just if it burns, heating it up at all will release fumes that will give you cancer... either do it in an incredibly well ventilated area, or wear a gas mask. no mater what DO NOT do it indoors!
I've never heard that just heating it up releases dangerous fumes (only burning). Got a source for that?

Posted: Mon Oct 01, 2007 7:43 pm
by Lentamentalisk
My dad works for the Healthy Building Network, so he knows all sorts of evil things that PVC does.

a clarification on this, heating PVC will release HCl, which when it comes in contact with your lungs creates Hydrochloric acid, at a much lower temperature than the burning point, which is when it starts to release dioxins.

Posted: Mon Oct 01, 2007 7:56 pm
by cwazy1
it helps to put end caps on it, and then heat it or else, the pipe will become oval.

Posted: Mon Oct 01, 2007 8:11 pm
by iknowmy3tables
you can use a propane blow torch but your result has a few burn marks I do it be cause boiling water never works well for me

Posted: Mon Oct 01, 2007 8:32 pm
by spuzi14
I beleive on Spudtech there used to be an article for creating PVC rockets (as ammo) that involved bending one end of the PVC outward in all directions like a spiral sorta thing. They used cooking oil I think for this...maybe it'd work for you?

Posted: Mon Oct 01, 2007 10:02 pm
by clide
Lentamentalisk wrote:My dad works for the Healthy Building Network, so he knows all sorts of evil things that PVC does.

a clarification on this, heating PVC will release HCl, which when it comes in contact with your lungs creates Hydrochloric acid, at a much lower temperature than the burning point, which is when it starts to release dioxins.
The only source I could find of what temperature PVC releases HCl had 200 degrees Celsius as the lowest temperature. PVC can be formed very easily at temperatures far below that.

Posted: Mon Oct 01, 2007 10:07 pm
by pyromaniac
spuzi14 wrote:I beleive on Spudtech there used to be an article for creating PVC rockets (as ammo) that involved bending one end of the PVC outward in all directions like a spiral sorta thing. They used cooking oil I think for this...maybe it'd work for you?
burntlatke

http://burntlatke.com/rocket.html

Posted: Mon Oct 01, 2007 10:18 pm
by Lentamentalisk
@clide
where did you find that info, because the PVC industry is about the slimiest trickiest group of people out there...
according to a book he has on the topic, PVC doesn't start dumping out the HCl until about 250c (480f,) but the amount of HCl that it spews out goes up exponential as the temperature rises. this means that at low temperatures, i.e. before the pipe gets very soft, you will probably be fine, but if it gets very soft, just know that you are poisoning yourself.

Posted: Mon Oct 01, 2007 10:24 pm
by Marco321
Lentamentalisk wrote:My dad works for the Healthy Building Network, so he knows all sorts of evil things that PVC does.

a clarification on this, heating PVC will release HCl, which when it comes in contact with your lungs creates Hydrochloric acid, at a much lower temperature than the burning point, which is when it starts to release dioxins.
My chemistry knowledge tells me HCL can only exist in solution.... Unless maybe water vapor....
But i think breaking the intramolecular bonds to create hydrogen and chlorine from PVC will require high temps, as someone said around 200*C. And at that temperature, there wont be any water for the HCL to be created, unless it forms hydrogen gas and chlorine gas, then when it comes into contact with water it from HCL, such as in your lungs or mouth.

Now refereeing to intermolecular forces in PVC, called dispersion forces, these hold the chains together. Dispersion forces are very weak, meaning only very low temperature is needed to brake most of them so it can be formed.

Both those points support the idea that that heat forming pvc at low temps is relatively safe, but should still be done in a well ventilated area for safety reasons.

I have seen alot of propaganda about PVC being the poison plastic, i believe there is a HUGE discussion on PVC dangers somewhere here.

On topic, i was watching TV and something on recycling came up, and one of the guys said if PVC burns, it releases toxic gas.

I hope this helped
Feel free to correct me if i made a mistake on something

Posted: Mon Oct 01, 2007 10:36 pm
by Lentamentalisk
Here is a great site for finding all about toxic materials.

Posted: Mon Oct 01, 2007 11:03 pm
by Redcoat
Pilgrimman wrote:I'd bend it with hot water, not a flame.

You Should use cooking oil It provides a higher heat.

woot! 700 posts! 8)