Is PVC cement reef-safe?

[kiknchikn]

I'm working on a project where I've created supports for the rocks in my new tank out of slices of PVC to keep the rocks from collapsing into my deep sand bed.

I decided that there was a good chance that the pvc would be exposed and stick out like a sore thumb due to sand being blown around or critters digging around, so I looked for a way to adhere sand to the PVC to make it more natural looking. After talking to some fellow club members we decided that PVC cement was reef-safe enough to work and so I tried it. To make a long story short, it ended up taking 3 very healthy coats of PVC cement and sand before they looked ok.

Now, after using so much PVC cement (about 8 fl oz), I'm wondering how reef-safe it really is for a 40g system.

The contents are:

Tetrahydrofuran 109-99-9,
Methyl Ethyl Ketone 78-93-3,
Cyclohexanone 108-94-1,
PVC Resin 9002-86-2,
CPVC Resin 68648-82-8,
Amorphous Silica 112945-52-5,
Acetone 67-64-1

Any chemists out there want to chime in and let me know if they are ok to use, despite the large amount of PVC glue? Perhaps I should put them in a bucket with a powerhead and change the water every day for a week or so?

[mflamb]

It is after it dries. I've used over a gallon each of primer/glue on my system.

[kiknchikn]

Even in large amounts that are exposed to water constantly? Just trying to make absolutely sure here.

I've found lots of threads in forums asking this question and "after it dries" is always the answer, but no one has used it like I am using it as far as I know. That's why I'm concerned

[mflamb]

I've used it for years and never had a problem.
How are you using it?

[kiknchikn]

I don't have pictures of the finished product yet, but I'm using it to adhere sand to the pvc sections shown below. Basically I coated the PVC with a very healthy amount of the cement and then covered it with sand. It took three such coats to get it fully sand covered the way I wanted.

There a total of six of these sections:


www.MikesReef.com

[Mike31154]

I'm also planning to use sections of plastic to support rockwork when I set up a 90 gal. in the future. I currently have sections of black household ABS pipe supporting rocks in my 70 gal. Not as elaborately carved as your pieces of PVC. I just cut a few circular holes and took a lengthwise section out to open it up, so it looks like a "C". The ABS comes in large diameter and is thicker walled than most of the PVC available. It was a little tricky since they're buoyant & wanted to float up when submerged. For the 90 gal I'll use some silicone to anchor them.
Anyhow, I didn't coat them with anything and my maroon clownfish have exposed one of them cleaning out an area below their BTA. Coralline algae is starting to take hold so it's not too much of an eyesore and the Clowns actually like the little cave they've created.
As far as I know PVC cement is inert once dry, but I'm planning to use two part epoxy left over from a canoe building project to coat the black ABS and cover with sand as you did. Epoxy is also inert once fully cured and I'm thinking it shouldn't take as many coats to achieve the desired effect as PVC cement. I think the epoxy is a little thicker when mixed than PVC cement and slower curing, providing more time to apply the sand. Epoxy costs more though.

[kiknchikn]

Nice to hear someone else is doing something similar to this

I thought about the epoxy, but I wasn't sure if it would stick well to PVC (not many things seem to) and was so much more expensive than PVC cement I decided to go with the cement. I really wasn't expecting it to take so many coats though and I ended up having to buy a second can of cement.

[JamesJR]

Tetrahydrofuran 109-99-9,
Methyl Ethyl Ketone 78-93-3,
Cyclohexanone 108-94-1,
PVC Resin 9002-86-2,
CPVC Resin 68648-82-8,
Amorphous Silica 112945-52-5,
Acetone 67-64-1

The Methyl ethyl ketone, acetone, tetrahydrofuran and cyclhexanone are all relatively volatile liquids and should evaporate off if you let them dry long enough. The PVC resins and silica are what remains when the cement dries and they are pretty inert towards water.

you may want to rinse them with warm tap water when they are dry but I wouldn't obsess over it too much.

[kiknchikn]

Thanks for the info. So far I've let them sit and dry and will continue to do so until I stop smelling the cement or for 3 or 4 more days... whichever happens first

[Megalodon]

Originally posted by kiknchikn
Even in large amounts that are exposed to water constantly? Just trying to make absolutely sure here.

I've found lots of threads in forums asking this question and "after it dries" is always the answer, but no one has used it like I am using it as far as I know. That's why I'm concerned

Remember, they use all this stuff for drinking water... for human consumption. It's potable. I know as nasty as it is, it's hard to believe, but it's true.