I have a water tap in the garden of the house. My little son keeps opening it regardless of how tight I close it. I would like to seal it off. I was hoping to find a metal cylinder shape element which I can screw on the tap water end. Any help would be highly appreciated.
Please note that I can't close the water supply to the tap.
You can get a hose cap and screw it on nice and tight.
You could also remove the handle if it has one screw in the middle.
You can also do a web search for "locking hose bib" and find a plethora of options.
Hose caps as mentioned above will definitely do the trick. You might think about just removing the spigot handle. They usually just have a screw in the center holding them to the valve stem.
I would put a hose on it and add a valve at the end--either one that he can't operate or one that's stored out of reach.
Other ideas:
You could also replace the hose bib with a different version that needs a special key to use it.
Here are some examples. I'm not endorsing the sites or the brands, they are just examples I found online.
"Standard" Square pattern keys
Some of the products are the full spigot and some are just screw-in replacements for the current valve and handle system. If you go this route, make sure you know what you need and what you're getting. That "child lock" system looks like it only works with certain brands of sillcock as a replacement for the valve.
You could use a tap lock.
They are common where I am from (South Africa), but a quick google and it seems you might have to import them since they don't seem common elsewhere.
Here are some links
https://leroymerlin.co.za/tap-lock-81440292
https://ecodepot.co.za/products/small-garden-tap-lock-galvanised
They might just have a different name in other countries.
If you don't like the "buy a lock" or "remove the knob" answers, you and your son could construct a small shed around the faucet as a bonding project. Then park your car in front of the doors.
