One of my ongoing projects is creating a system to draw a little water from the canal at the end of the garden for the plants on that patch of land but without leaning down with a bucket or watering can. The current state of play is a length of plastic downpipe with a cap on the end to be submerged and a few holes about 40cm up. It can be poked in the water and then tipped back so most of the captured volume flows out into a container sitting on the bank. I’m gradually working through an iterative design process, for example realising that too many holes let too much water out. Eventually, I might get round to constructing a pivot mount for it to minimise the effort involved and to avoid any risk of dropping the pipe into the water.

The next step is adding a section onto the outlet end to direct the water more directly down. With a straight tube, it rushes out at speed and is quite hard to aim into the tub trug I am using. I had planned to 3d print an angled joint to connect a 2l water bottle to perform that job but then I got given a short length of offcut tube and decided to buy an angled joint. I might still include the bottle to slow down the water output but I’ll probably see how it works with just the joint and extension first.

Mind you, I almost didn’t buy the joint. It cost £3.97 in B&Q for a joint giving me about a 60° angle. When I got it home, I weighed it, which is where the 131g of the title comes in. I’d reckon that a spool of printer filament costs about £15 and so I could have printed an equivalent part for just over £2 of material, or less if I designed a lighter weight one. What made me decide to go ahead and buy it?

Partly, it was not knowing the actual weight. I’d estimated about 250g, which would put me closer in price terms, particularly given the printer running costs. I don’t think it consumes that much power but the figure is going to be somewhere over zero. More of a consideration was the cost of the design process. Although the basic shape is quite simple, it can take a while to dial things in and that also tends to consume filament with test prints. There are also some design features on the commercial project that mean it can be twisted on and hold firm – my printed parts so far are a snug fit but I’m relying on hot glue joints to keep them in place. Even though I enjoy 3D design, I only have 24 hours budget of time each day and much of that is required for other important things (like sleeping!).

There is also the longevity question. The injection moulded commercial part should last for years, probably even decades. I’m not sure how long my printed parts will do, particularly given the water and sun this mechanism is going to be exposed to. I think a lot of people exaggerate how quickly printed parts fail outside and I’ve seen plenty of YouTubers I’d count as reasonably trustworthy demonstrate five or more years of good use for certain parts. However, lifespan and what to do with parts when they do break are considerations.

All in all, getting that one joint was probably the best choice to move my project forward. However, that would change if I had a lot more parts to print. So far, I’m up to about 100g and a little bit of hot glue in terms of what I have printed. Without that ability to print and design, I probably wouldn’t have kept the main pipe (rescued from a skip) and the (estimated) £15 cost to carry the experiment as far as I’ve got would have left me reaching down with a watering can and hoping my back would hold up.