qubster

może się przydać, nie sprawdzałem czy działa ta metoda, tu cały artykuł : https://www.instructables.com/id/How-to-build-a-Kegerator-1/
"This step is crucial because if you cut into a refrigerant line you will be shopping for a new fridge!
The refrigerant lines run along the top of the fridge and are covered up by insulation, and can be hard to find.
There are a few ways to locate the lines, but someone way smarter than me came up with the clever idea of using cornstarch and vodka.
- Remove the plastic top of the fridge (I ended up throwing it away in favor of the black metal finish)
- Plug in the refrigerator and let it run for about 30-40 minutes
- mix cornstarch and vodka together into a paste (about the consistency of sour cream)
- spread the paste around the (top) surface of the fridge
- the refrigerant lines are hot and will cause the vodka to evaporate from the mixture faster than the surrounding areas, leaving a lighter colored line that indicates where the refrigerant line is.
- mark this location with tape, then clean up your mess
Once you find where the lines are located, you can layout where you want to position your hole."