Best way to connect and seal two plastic water containers?
Best way to connect and seal two plastic water containers?
I'm launching a little balcony gardening project that involves water reservoirs. I don't have much experience with these kinds of projects, so I need a little help.
Due to some dimensional constraints, I will need two regular plastic containers (your typical storage containers), and I was hoping to get away with only including a way to fill one of them. That means I will need to connect it to the other in some way. So I thought I would just drill a hole in both of them and stick a pipe between them.
- What is the best way to drill holes in plastic without risking any splitting?
- How do I make sure that the holes are water sealed afterwards? Can I glue around the pipe and plastic box?
Look up bulkhead fittings. Use them at work to connect chemical tanks together.
bulkhead fittings
Ah, I was struggling to find the English term for that. Yeah, those are best, but you can improvise one with some threaded connections and some cut-out rubber (taken from an old bicycle interior tyre for example) or (not nearly as good) teflon tape.
This is what you’re looking for.
Cheers, I'll look into those! :)
Instead of glue, I'd recommend getting some silicone sealant. It's pretty much designed for this sort of thing
Marine silicone is specifically formulated to be water tight (and safe for aquarium inhabitants). It can be found at specialty salt water aquarium stores.
Good idea, didn't think about that!
I'm not sure of the scale here, but you might also consider using a hot knife to cut the holes rather than drilling, and flexible plastic tubing rather than a pipe
Would it be possible to maintain at least some water in both containers? If so, a simpler approach might be to try a siphon. Here's an image showing a (way bigger) example, but the theory would be the same for your containers.
Thanks for the suggestion. I think it would be difficult to maintain water in both, and I don't have too much leeway in terms of height differences either.
I would say for 1. melting instead of cutting is a sure way, but any kind of cutting that doesn't deform the container too much usually also works. You can also take a small drill and make a series of holes in a circle and then cut it out from there.
As for 2. you need to experiment with the compatibility of glues with the plastic of the container. A two component epoxy glue will nearly always work, but is probably overkill. Another common method is to used rubber gaskets and screw on clamps of some sort.
P.S.: in some cases a simple siphon will also work if you can ensure it never falls dry.
Melting sounds like a good idea. What would you typically use to do it? A soldering iron perhaps?
When you say compatibility, do you mean in terms of adhesion, or are there other things I should be concerned about?
The proper way to cut the hole would be using a drill with a hole saw, drill in the center pilot bit like normal and then cut the actual hole with the drill running in reverse for this specific application. If you ran the saw forward the teeth of the hole saw will be far more likely to catch and crack the container.
Whatever method of cutting you use, make sure to clean up the edges with some sandpaper so there isn't a rough edge.
A bulkhead fitting should have a rubber gasket that will seal properly without additional sealant, but a nice fat bead of clear silicone sealant will help if the spot you put the hole at isn't a perfectly flat surface and the plastic doesn't deform ideally when you tighten the fitting. Aquarium silicone would probably be ideal for planter use, bathroom or construction silicone can offgas harmful stuff for plants.
The sides of the container won't be parallel to the ground, so a straight pipe will put strain on the container that will lead to a failure. You will probably want to use flexible hose to connect the two containers, but two 45 degree elbows at each end of ridgid pipe(so 4 total) can take the strain out once you play with the orientations.
If you use a hole saw I would recommend you drive the drill bit in reverse. It will make a cleaner cut and in general is just nicer to do with plastics.
You could buy some quick fit hose fittings with o-rings and use those to attach the pipe. It'll work just fine.
Any hot metal thing will do. You can combine the melt with the drill method by poking a series of smaller holes with a hot nail. Better do it in a ventilated space though... a balcony will do ;)
And yeah, some glues just don't stick well to certain types of plastic. You can try roughen the surface up a bit with sand-paper but it will not always work and having a leak because you accidentally slightly moved a container is annoying. IMHO the rubber-gasket way is the most durable way of doing it.
Your local DIY shop should have pipe fittings and PVC cement for any configuration that you need. Grab a hack saw or pipe cutter for the piping and use a hole saw to avoid splitting the containers.
Our local DIY (Lowe’s - US) generally offers classes for whatever you’re likely to be building at any given time of year. It might be worth a phone call to ask.
