Is an efi shield just a barrier?
I have a drone which flys fine without an electronically stabilised camera gimbal.
I have managed to track the problem down to interference from the motors on the gimbal.
Is an efi shield something you can wrap round the motors to reduce it or as I suspect it’s way more complex?
Any advice would help

Is an efi shield something you can wrap round the motors to reduce it or as I suspect it’s way more complex?

Basically yes, although you will get leakage, both conducted and radiated, out of the the two holes: The axle exit and the power cable exit. You can fix the conducted leakage by adding ferrits to the power cable.

Another potential issue is heat, if you wrap foil around the motors, they will get hotter. Normally you’d use a mesh for this sort of thing (lighter, cheaper, lets air in etc).

You might just want to try suppressing conducted radiation from the motors with ferrits and / or capacitors as the interference may just be conducted via the power supply.

A tin foil hat provides some EFI supression but nothing like the ferrous type materials designed for the purpose.

Check it is not noise coming through the wiring harness first, you need to work out what kind of motors/electronics you have on the gimbal to narrow down how to electrically stop/supress noise from them, e.g. if there is a gyro with a crappy bruahed dc motor then you might just need a shunt diode.

P.S. ferrites not ferrits, pmsl:-D

If it comes down to adding electronics to the device it’s going in the bin. As it is way beyond by experience.
And just typically Chinese crap.
I will experiment with some foil fist selectively added. Ferrites are like magnets with holes in – more like a large stoat?

“I will experiment with some foil fist” hmmm sounds pleasant/painful, what about fixing your drone though?