You can assemble your first pulse metal detector and, here, it came to manufacturing a search mono coil. And if you have some financial difficulties, You faced a difficult task – to make the coil yourself from the cheapest possible materials.
The easiest way for self-production seemed to me such a structure: we take a disk made of sheet material with a thickness of ~ 4-6 mm. The diameter of this disk is determined by the diameter of the future winding (in my case it should be equal to 21 cm).
Calculations showed that to obtain a sheet of 5.5 mm thickness, you need to take 18 layers of glass fibre. To reduce the consumption of epoxy, fibreglass is better to pre-cut into circles of the desired diameter.
For a disc with a diameter of 21 cm, 100 ml of epoxy resin was just enough.
The remnant of PCB was just enough for the ears to attach the sensor body to the rod. Drank two pieces on each ear (so that it was durable!)
Then, using a round file, prepared the grooves for the conductors, started the connecting cable through the hole and pasted it tightly:
To prevent strong bends, the cable in the input area had to be somehow strengthened. For these purposes, I zayuzal, out of nowhere who took from me, just such a rubber garbage:
This manipulation allowed to throw 168 grams of excess weight. At the same time, the strength of the sensor practically did not decrease, as can be seen from this video: