What to do when pupil destroy lab equipment? I am teaching robotics at something like an afterschool but is free for everyone aged 12-19 years. 

The first problem I encountered was poor equipment and facilities, but I obtained some funds and I was able to buy laptops, new soldering irons, Arduino starter kits and more. I was reticent to put into use all at once and I opened up only one soldering iron to see how pupils would use it. 

Of course, we have safety instructions which include rules like do not degrade lab equipment and I repeated rules but after a few weeks pupils started to play putting soldering tip to wet sponge so water boiled and sounded nice to them, and what disappointed me was some holes in the soldering iron plastic case.

I am the only teacher, I can't supervise all pupils at once and teaching here is consuming because everyone is at a different phase of constructing an electronic circuit for example.

I was thinking to track the usage of equipment and with the very first occasion to punish the children by calling home to his parents or even to exclude them, but this seems unfair since everyone could damage equipment intentionally.

What should I do to be able to have all of the equipment on the table but this kind of damage to not exist?

I don't care if damage occurs when equipment is operated wrong or damaged by mistake. I don't want pupils to think of equipment like toys and play with them damaging them and workspace.

Other cases of damage:
- Cutting wires with wirecutter even if they don't need it
- drilling holes in worktable with a drill bit
- melting plastic with the soldering iron tip

I know, partially it's my fault because I can't keep everyone at the same time captivated but damage should not occur.

Thank you for attention
How should I prevent damage to equipment?

Number each piece of equipment, assign each student (or each group of students) a number, and instruct students (or groups of students) to use only their numbered piece of equipment. Explain that each student (or group of students) is responsible for their piece of numbered equipment and they will face punishment if equipment is damaged.