How to build a copper overhead irrigation system?

[oli]

Hi all - i'm looking at building an overhead drip irrigation system for potted citrus, figs and more, mostly in pots around 20-30cm in diameter, but also 2x large half-wine barrels. Most pots are right next to each other, so some emitters / emitter arms might be about 1-1.5ft apart on the main line.

Cost is not an issue, it's a small garden and so my priority (apart from the functional irrigation) is something beautiful to look at and be around, and minimising of any plastics.

So i'm looking to build it entirely from 13mm copper pipes secured overhead (about 6.5-7ft ft off the ground) along one single line, with a t-join breaking out a perpendicular line right in the middle 3 metres long, to feed the 2x barrels and another couple of pots.

In total, there are currently around 20 pots that i'll be feeding with it.

Compression-fit for attachments between emitters and lengths of mainline pipe. All of the pots vary from 1 - 1.5 metres off the ground. From a birds-eye view, it would look like a giant "T" - 6 metres long along the fence, with one 3 metre arm coming out from the middle. The lines will be supported by some mounts on a fence and a couple of DIY pillars to carry the load at each end. Rachio or Bhyve tap timer at the front end.

I'm going to measure the pressure of the tap, but it's got a bit of kick and currently feeds a ground irrigation system with 30-40 drip punctures across a PVC line running about 50 metres.

I'm looking for advice on emitters and would love any insights. The main line from the tap will be about 6 metres long, and I want to avoid having 2x near-spaced drip emitters over each pot just to get better surface coverage in each pot, so I'm trying to find emitters that have arms with 3-4 drip holes fanning out from a centre point. I've seen brass spinning sprinkler type ones, but i think they'll cast the water too far. The emitters must be brass or copper.

My main questions:

1: Is a 13mm mainline copper pipe fit for purpose? Total run length may be around 10-11 metres, and ~20 pots for 25-30 emitters total.

2: In order to get the emitters a little closer to each pot, will attaching a 1-1.5 foot arm of copper directly down from the mainline closer towards the pot have any adverse effect on pressure that I should consider? This might add another ~5+ metres total to the run length, with the emitters at the end of each of these arms from the mainline.

3: Since the barrels will require more than the pots, are there any emitters that allow a much slower flow rate than others, or is pressure across an entire line of emitters uniform? My non-physics inclined brain tells me that even if the general pressure along a line is the same inside it, that this must be possible if some emitters have smaller/less outlet holes. Or is this best solved by having a section of pipe over the barrel that has 2-3 separate emitters extruding from it and line pressure equitably split between them thus solving this by simply having more individual of the same emitters?

4: Do bunnings have any sort of brass/copper emitter that might give me a wider array of drip holes to more thoroughly cover the surface of each pot?

Thanks for reading this onslaught

[Jewelleryrescue]

Hi @oli 

I like your copper art work watering system it has some great merits.

You can use a new system of joining copper pipes that requires no soldering or heat simple push fittings called SmarteX I have included links to several fittings you will need in the text.

You will need to also buy some specialized but in expensive tools to use SmarteX products and it will be best to find youtube showing its ease of use.

Tools

Deburring tool

SmarteX - C Fitting disconnect kit  for copper pipe.

Copper pipe bending tool.

pipe cutting tool

Ok Your  questions 

1.   13mm copper is well matched for your needs, I would polish the copper and later once it is all installed spray it with clear spray varnish to preserve the bright copper look rather than let it return to the muddled dull red aged look.

2 Your copper pipe will have plenty of pressure to spare for 30+ meters of piping and multiple junctions as I don't think you need as you say big sprayers/emitters.  

3 and 4 There are no commercial copper sprayers or emitters for sale anywhere i know of so you will need to make custom system. I am thinking your copper pipe coming off a Tee join   and terminating with a Brass cap So imagine your 13mm copper pipe bending artfully towards you pot maybe like a horseshoe shape as a guide and the end has the cap.  To make the sprayers small 1mm holes drilled into the copper pipe where you want the water to come out.  You want more water, and a larger spry area drill more 1mm holes along the pipe.   You can drill 50 or more 1mm holes and still have good water pressure.  If you want higher water flow drill 2 x 1mm holes or a single 2 mm hole.

- Water pressure is adjusted at the main copper tap 

The only other way is to find an artistic plumber willing to spend the time creating your watering art work. I would have your design  ready drawn  up  so the plumber can quote on it.

[EricL]

Hello @oli 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your irrigation system.

That would be a beautiful looking irrigation system once you have it assembled. It's great that you've received excellent advice from @Jewelleryrescue. Using the SmarteX Push fit System is an excellent method of joining copper pipe and saving you from having to weld and solder the joins. 13mm copper pipe will provide you with a long service life and it can easily be repaired should a leak occur.

It is technically possible to lower the pressure inside the system by installing a Pope pressure reducing fitting. For ease of use, I suggest doing a hybrid installation of copper and plastic irrigation pipe which will still allow you to use traditional fittings such as drips and sprayers. My only other suggestion is that if you do decide to use all copper, make sure that the end of the pipe can be opened so that you can flush out the pipe work.

If you have any other questions we can help with, please let us know.

Eric

[Jewelleryrescue]

Hi @oli 

Thinking about @EricL 's  idea of using conventional plastic spray tips.  If you practic drilling increasing hole sizes in a test bit of copper tube basically at approximatlty 4mm hole size

There are many Plastic Micro sprayers in a number of spray petterns and  volumes that will be interchangable and there plastic threads should thread into the copper pipe once the correct diameter is found.

[oli]

Unreal. Thanks so much for the very thoughtful responses! I just had some test pipe, cutters, brass end caps, copper olives and t joins arrive today and i've been enjoying getting the hands on them and understanding how they all piece together. And you're right, I scoured online and in brass, I couldn't find a single drip head available anywhere - brass emitters were all high volume sprayers or misters only, and have also come across a bunch of self-regulating plastic drippers so like you say, that will be the go. 

I'll give the copper hole drilling a go - if the threads are just forced into the pipes, will they be water tight? I can imagine how that might work with PVC/any synthetic pipe especially if it's heated, softened and then pressed in, but my brain can't understand how they can be totally watertight when pushed into a copper hole. Would I benefit from using any teflon tape wrapped around the plastic dripper threads when pushing them in?

[oli]

Thanks Eric - i cant wait to upload the snaps of the finished setup here. Just had a swag of copper & brass fittings arrive from Bunnings today to get a feel for the materials, including an end cap to flush out the main line when it's setup.

My tap outputs 1600 litres per hour, and i'm beginning to understand that for that pressure a pressure reducer (as you noted) is mandatory for a drip setup rather than optional.

If I get self-regulating plastic drippers that put out 2-4 litres each per hour though, in a fully sealed setup with 25-30 drippers where those drippers are each regulating their own output regardless of the line pressure, do I need a pressure reducer at the tap?

[MitchellMc]

Hi @oli,

I'm not aware of any drip fittings that would be suitable for inserting into the side of a copper pipe. As you mentioned, if you were to push them into holes, they'll simply leak. If you were able to find brass fittings, then they could potentially be soldered in place. You could try glueing them in, but there are not many types of glue that would suit that purpose. Epoxy putty could work, but under pressure and in a wet environment, that might not hold either. 

Teflon tape could work, but as this is not a common method for irrigation installation, a bit of trial and error will be required.

A pressure reducer is always required in irrigation setups to prevent the drippers from being blown out of the pipe. In your case, this is all the more important.

Mitchell

[Jewelleryrescue]

Hi @oli 

If you experiment and drill the best hole size into the copper pipe the thread on the plastic micro sprayers will self-screw into the copper pipe as the wall thickness is thin.  This will mean no glue needed and you can at a later stage swap out sprayers at need simply by unscrewing them is my proposed goal for your system.

So I measured the diameter of a micro sprayer it is 4.6mm.  So if you drilled a hole 4.6mm the sprayer will push in but just pop out straight away as the hole is the same size naturally.

So I propose you drill a smaller clean hole 4mm (sharp new drill bit  Plus 4mm is a standard size drill bit)

Now use the plastic thread on the micro sprayer to screw it into the 4mm smaller hole in the copper tube.

If the hole at 4mm a little tight to screw into then redrill the same hole a little to slightly widen the hole so it is still tight to screw into but not overly hard to turn the nozzle.

The end result is we have a  Micro sprayer screwed into place and can be interchangeable  with other micro sprays as long as the thread is the same.  

Don't force the micro sprayer fitting in a direct push into the copper this will strip the plastic threads, and they may pop out later. But this is an experimental project so let's play and see what works best. 

I would not use the smooth arrow shaped push in type of micro sprayers they are designed for Polypipe that will stretch around the arrow and lock onto it whereas copper won't do that it would leak if you forced it in.

Also, I if you wanted to seal a now disused hole in the copper pipe.  I would use a screw in Veri flow trickler dripper with the screw thread.   As these can be adjusted down to zero flow and will just be a good plug.  There are no screw in plugs I am aware of just the push in types which may leak or pop out again?

And for ease of flushing your whole dripper system simply add a smarteX tap instead of a end cap this way you can  have a pipe or hose drain into the garden off the tap as you wish. As taking those smarteX caps of a pipe is a little cumbersome.

[EricL]

Hello @oli 

On the understanding that you are using regular irrigation pipe in combination with copper pipes it would be best to use a pressure reducer. Unless you are doing a mixed sprayer system along with pop-up sprinklers, then I would suggest creating a secondary line for the high-pressure sprayers. But for the drippers not a lot of pressure is required. Installing a pressure reducer would be prudent and it will put less strain on the plastic irrigation parts of your system. 

If you need further assistance, please let us know.

Eric