How to cut flexible PVC straight

[Neaco]

I have a PVC cutter that cuts up to 1 5/8 PVC.  I am trying to cut 1 1/4 flex pvc but it always makes an oblique cut.  It cuts straight on regular stiff pvc.  Not sure if it is because the pipe flexes as it get cut or if is because the flex pipe has an underlying spiral pattern.  Any advice on how to make the cut straight on a flex pipe?  

[lstmysock11]

https://www.lewiscontractorsales.com/knipex-flexible-hose-and-pvc-cutter.html?msclkid=1c485fb2096d1885a0533ff74ec6319a, not sure but maybe this might help

[Neaco]

I have a cutter like that.   Looking at the picture on the website gave me an idea to put a 1 inch hard PVC inside the 1 1/4 inch flex PVC and then make the cut.  It was very difficult to cut and I felt like I was going to break the cutter.  After cutting part of the way through I Took out the hard PVC and looked at the flex tube.  Still an oblique cut.  

[Origami]

It's the underlying spiral reinforcing material that you're working against. I had the same thing happen years ago when I plumbed pieces of my tank with flexible PVC (spaflex). Just take a pair of wire cutters and cut through the harder stuff and trim it up. It won't be perfectly straight, but it'll work. The only way that I've gotten a straight cut was to cut it with my power miter saw. You might be able to take a similar approach with some power tool or a hand miter box. However, the regular PVC cutter will basically glance off the spiral reinforcement and give you the result that you're seeing above.

[Neaco]

Are you talking about a large pair of wire cutters to cut through 1 1/4 inch flex PVC all at once or a small wire cutter that snips all around it somehow.  Are you talking about using the m wire cutters after I make the initial oblique cut?  Thanks 

[Neaco]

Just now, Neaco said:

Are you talking about a large pair of wire cutters to cut through 1 1/4 inch flex PVC all at once or a small wire cutter that snips all around it somehow.  Are you talking about using the m wire cutters after I make the initial oblique cut?  Thanks 

 

[Neaco]

By the way do you put silicone on the threads when connecting  threaded PVC?

[WheresTheReef]

2 hours ago, Neaco said:

By the way do you put silicone on the threads when connecting  threaded PVC?

Teflon tape. Thread it on in the direction of the threads. I’m sure YouTube has a demo video on how to apply it.

[flooddc]

You should not use plumping tape (teflon) on pvc thread. It can stress the pvc and cause leak and possibly crack.  
Teflon tape designed for metal fitting.

[WheresTheReef]

2 hours ago, flooddc said:

You should not use plumping tape (teflon) on pvc thread. It can stress the pvc and cause leak and possibly crack.  
Teflon tape designed for metal fitting.

Chuck what do you use? I’ve used it more times than I can remember and never had an issue. Willing to bet (right or wrong) that I’m not the only one :). I only wrap the thread a couple times and very tightly. The issue is when people add too much tape and over tighten. I have also used pipe thread sealant in the past.

 

I prefer to glue joints in most cases.

Edited March 14, 2021 by WheresTheReef

[flooddc]

39 minutes ago, WheresTheReef said:

Chuck what do you use? I’ve used it more times than I can remember and never had an issue. Willing to bet (right or wrong) that I’m not the only one :). I only wrap the thread a couple times and very tightly. The issue is when people add too much tape and over tighten. I have also used pipe thread sealant in the past.

 

I prefer to glue joints in most cases.

I don’t use anything on the thread. For bulkheads, I put a small beads of silicone on the inside of the tank for added security. Other than that, hand tight threaded pvc and 1/4”+ with a wrench.

Here is the info link to pvc fittings.

https://www.lascofittings.com/threads

[flooddc]

Bryan, are you using the pvc pipe as drain or this going onto a pump (pressure)? 
i usually cut it with a oscillating saw and trimmed the end. Just eye ball it, not perfectly straight but pretty good clean cut

I use pvc glue if the pipe is used on the pump side. pipe and use silicone on the drain side. 
 

[Neaco]

Pump side.

Also is it really not a good idea to connect schedule 40 with schedule 80 PVC?   Specifically do you think it is OK to have a quick disconnect with 80 on one side and 40 on the other?  ( it’s just easier to leave the 80 in place on the far side and add the 40 on the close side without having to do more cutting and gluing and also since I have a 40 and not an 80 at home right now and this project is going on today).  

[Origami]

Are you talking about a large pair of wire cutters to cut through 1 1/4 inch flex PVC all at once or a small wire cutter that snips all around it somehow.  Are you talking about using the m wire cutters after I make the initial oblique cut?  Thanks 

Just thru the reinforcing coil. The only way that I used to get a really clean cut was to use my miter saw. It's not all that important to have it exactly straight when gluing it up. So don't worry much about that.

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[Origami]

Schedule 40 and 80 connect just fine. We don't have anywhere near the pressures needed to have concern.

I use pvc cement on all connections except threaded. For threaded, I will use teflon tape or pipe dope if I'm afraid it'll leak. The dope is handy on large, threaded joints, like the output side of my external Reeflo pumps. Be careful, though. Both teflon tape and pipe dope lubricate the joint and invite you to overtighten which can lead to failure.

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