Flex PVC

[AtlanticBlue]

I'm getting ready to 'redo' my 180, I am thinking about using flex pvc as opposed to hard pvc. I have seen quite a few tanks on here using it...is it a good idea? Some reasoning would be...

It's quieter as it has more give than hard pvc
Less 90 angles
Just plain easier

Any thoughts?

 

[Jefe12234]

I used a lot of it on my newest tank and I think it works great. My only concern would be with trying to bend it too tightly. It's flexible, but still a bit stiff. If you try to make a tight curve with it, it may put too much torque on a bulkhead or other fitting. It works great for gentle curves, but use elbows for tight curves.

 

[AtlanticBlue]

Can you hook elbows up to the flex pvc?

 

[shag26272]

you can use it just like regular PVC, I use it. Make sure you have a heat gun to form it.

 

[AtlanticBlue]

<a href=showthread.php?s=&postid=12512892#post12512892 target=_blank>Originally posted</a> by shag26272
you can use it just like regular PVC, I use it. Make sure you have a heat gun to form it.

??? I've never used the stuff. What do you mean?

 

[shag26272]

well it comes in a roll and is basically stuck like that until you heat it up, its pretty stiff stuff especially the 1 inch and larger

 

[Jefe12234]

Flexible PVC (or spa flex) can be glued into standard PVC fittings. There's a special kind of glue for use with Flexible PVC. Some people use the regular PVC glue without problem, but get the stuff for flexible PVC. And a heat gun will make flexible PVC easier to work with, but it's not necessary. You can still bend the stuff however you want, it just has a tendency to go back to the coil shape it was stored in.

 

[tedu]

I've had good luck placing it in a 200 degree oven until it gets warmed up (almost too hot to touch), this relieves the curves that have 'set'.
Then lay it out straight on a tile / concrete floor to cool and it's much easier to manipulate.

 

[kingsland]

Use a medium body PVC glue. You can also lay it out in the sun on concrete for a day and it will relax.

 

[shag26272]

yeah I forgot about the medium glue, no special glue is necessary

 

[BeanAnimal]

<a href=showthread.php?s=&postid=12517017#post12517017 target=_blank>Originally posted</a> by shag26272
yeah I forgot about the medium glue, no special glue is necessary

It should be HEAVY bodied cement or a high solids content like Rain-N-shine. The better alternative is to order the glue for FLEX PVC. Don't pay any attention to the literature at Lowes that says regular glue and primer can be used, it is nonsense, just like most product literature authored to help the big box store sell to home owners.

 

[shag26272]

I didnt buy it from lowes, but I have used it many times with the medium glue and it hardens like cement

 

[BeanAnimal]

I was referring to the literature at Lowes that directs home owners to use primer and standard PVC cement for the Flex PVC. It is 100% nonsense. Lowes does not have enough demand to sell Flex PVC cement so they direct people to use the wrong product.

The "medium bodied" solvent cement may be ok, but it is still not as heavy as the Rain-N-shine or the proper Flex PVC cement. I have been able to pull joints apart by hand when standard PVC cements (including medium bodied) have been used. The problem is that the FLEX pvc does not solvent weld like hard PVC. There needs to be a filler to create a solid bond. Hard PVC needs very little filler because the joint is very tight and the "melted" pipe mixes and dries back together to form a solid bond.

You can get away with standard PVC glue, but the joint MUST have no stress on it. That is contrary to the way most people use the stuff. They glue it and then force bend the flex pvc to conform to an unnatural (unrelaxed) shape. This puts A LOT of pressure on the joint. That is why heat forming the flex is so critical, especially when using the improper solvent cement.

 

[shag26272]

yeah, I see what you mean, I use it in 1 in. and 3/4 I wouldnt put that much stress on it with any type of glue, it is too stiff

 

[HarleyDude]

Really, the regual PVC works fine with Flex. I have over 500 feet of it with all my tanks and have not had a problem unless I made a mistake. I did not use a heat gun, but there were times when I wish I had.

 

[ReefEnabler]

So far I've been using Oatey Rain-n-Shine (for PVC and ABS), in the Red and white bottle.

the joints I get are strong. I cannot pull them apart by hand. So far I've just used it on the plumbing for my skimmer (Iwaki55 pump for ETS 800) and drain lines.


I'm about to use it on the return lines and closedloop of my display tank so those will be under more presssure. Just wanted to make sure that the Oatey Rain-n-Shine (without any primer) is a good choice for the rest of it.

I saw a primer mentioned above, but I'm not sure what kind of primer works well for spaflex (I know the purple kind will ruin the joint, tested that for myself and its true).

 

[ReefEnabler]

doh, I'd like to correct my nonsensical post above:

I've been using Oatey All Purpose in the red and white can..... the Rain-n-Shine is the blue one that I've only used on my rigid PVC.

so Bean, you're saying that the Rain-n-Shine (blue stuff) is much better than All-Purpose (clear), but that no primer should be used either way???

How much better is the 'PVC Flex' cement??

I recall a similar thread a while back where people were suggesting the All-Purpose by itself, which is why I used it so far.

btw I asked the same question in the last post of my build thread:
http://reefcentral.com/forums/showthread.php?s=&postid=12669190#post12669190

 

[mm949]

u need to use the blue glue cuz spa hose can flex....regular clear glue is intended for solid pipe...if u use clear on spa if the joint flexes the glue wont ...causing it to crack(leak)
ive piped many tanks in my day and ALL flex pipe done in regular glue WILL come apart over time