Thread: 6" PVC pipe puzzle

Originally Posted by Ross

Bob

The first time I saw it done was by a builder working on my house and he used a blow torch on 100mm pastic pipe. It was very fast, the pastic was like rubber till it cooled. He all so enlarged one end so the pipes fitted together.

I use a heat gun and do it slowly, it won't do a tight radius . Think about how metal workers bend shapes and make up a jig using a flat board with a couple of posts to bend the pipe against as you heat the area where you are bending.

It works on 100mm so it should work on 150mm. Get some scrap and give it a go.

Ross

Thanks Ross, I have done it with 100 mm pipe but 150 mm is thicker and stiffer, so getting the heat even all over is harder and I found it just buckles - maybe I was not patient enough.

I found that unless the pipe is supported, the heat bending method also constricts the pipe so any gain in retaining a smooth wall is lost in a constricted pipe

I also made a 4 jaw WW lathe chuck out of HDPE that I use to expand the ends of 100 and 150 mm pipe. I run the lathe with the pipe in place and heat the end with a heat gun. Every minute or so I stop the lathe and apply some outward pressure.

Originally Posted by Ross

Forgot to mention this is a job for doing outside the shed, the fumes from the plastic are toxic.

Ross

A powerful enough DC that vents outside the shed allows it to be done inside the shed.

[QUOTE=BobL;1424181]Thanks Ross, I have done it with 100 mm pipe but 150 mm is thicker and stiffer, so getting the heat even all over is harder and I found it just buckles - maybe I was not patient enough.

I found that unless the pipe is supported, the heat bending method also constricts the pipe so any gain in retaining a smooth wall is lost in a constricted pipe


Yes I spent over an hour on each bend.

Did you try with a stronger heat source? I tried with a solar wax melter but it was too hot for the 100mm pipe.

Ross

I tried a range of stuff including using two heat guns while turning the whole of pipe on a lathe to get the heat as even as possible. The whole thing got too floppy and would kink. It may be better to just heat a 100 mm section at a time and induce a bend in that section and then move on. I also tried boiling water but that did not seem to be hot enough.

Ideal way to bend PVC is with a large spring inside to keep its shape. For this size you need to find a large slinky. Perhaps you could make your own from a medium gauge wire.

I had to do a similar thing at a ski lodge for some drainage many years ago.

I think a little outside the box sometimes, so here is my suggestion.

Fill sections that you want to cut with water and freeze it.

Cuts easily with no flexing because it is solid, doesn't matter what size saw or teeth because you have a solid "log".

Cut parts are nice and clean when the ice melts.

A good few years ago I watched two sparkies bend a 6" orange pvc pipe by pouring petrol on the ground and setting fire to it. They made it look easy, they'd done it before and it only took a few seconds to get the bend that was required.
Ah good old days, petrol on ground, setting fire thereto, I'd like to see them trying to do that on a building site today.
In regard to the original question re tpi of bandsaw blade, is there an issue with heat generated by a powered blade melting the pvc? I've cut plenty of pvc pipe over the years, but only with a hand saw, usually about 14 tpi. A few years ago I was attempting to cut some sort of flat plastic with my jig saw and ended up with melted plastic stuck to the blade.

Geoff.

I have seen the heating and bending done as well. The chappie used to fill the pipe with sand to keep it from collapsing and it was very successful. He only bought straight lengths and made every single bend from them. There was the occasional whoopsie but on the whole a lot cheaper.

I've just done some pipe work, was thin wall 75mm (3") & I found that I could cut it fine with a 4TPI blade so long as I didn't force the cut.
The only time I have a piece snap out was when I was trimming an end & pushed it through the saw too quick.

Bruce, I have made all my connections from thin wall 100mm/4inch PVC ducting, and I just jam it full of shreaded paper, supports the pipe and works like 's ice method but not as messy on the machine and you can reuse the paper after each cut. Also if you want to make your own flared sockets, I have turned some mandrels out of scrap MDF, and use the heatgun to soften the PVC till like putty and have a wet rag to cool it when stretched onto the mandrel.
regards,
Crocy.
P.S. did turn me into a "senior member", I am not that old and I resemble that remark, LOL and a Happy New Year to all.

Originally Posted by Old Croc

....P.S. did turn me into a "senior member", I am not that old and I resemble that remark, LOL and a Happy New Year to all.

Nuh, happens when you are here too long, you can change it yourself, that is why I'm a 'Timber Hoarder'

Originally Posted by Old Croc

. . . I just jam it full of shreaded paper, supports the pipe and works like 's ice method but not as messy on the machine and you can reuse the paper after each cut.

Good idea!

Originally Posted by Old Croc

P.S. did turn me into a "senior member", I am not that old and I resemble that remark, LOL and a Happy New Year to all.

Wait until you reach Decrepit.

Interesting idea.

[ame=http://www.youtube.com/watch?v=aZ4U7XdTIFQ]DIY - Bending PVC Pipe with Air Pressure - HenryWitecki.com (Cataclyst) and Chris Powell - YouTube[/ame]