Simple test for detecting galvanized ?

Um, look inside to see if it looks like zinc maybe? Or pay someone who knows how to handle gasoline tanks to coat it with something compatible with diesel? Gasoline tanks are nothing to fool with if you're untrained.

This warning suggest looking inside with a candle or lighter. That would open the tank for easy inspection. :-))

Ni-don'tdothat-ck

I have found this:

So i will test with some on a cotton swab and check which color it turns, black is zinc.

You're aware, I hope, that gas tanks that are "empty" can have enough residue in them to stay explosive, sometimes for years, right? I went to an emergency call a few years back where a fellow was cutting an old gasoline tank, had been empty for as long as anyone could remember. Took him a couple days to die of his injuries. This isn't the time for random experimentation. Take it to someone who knows how to handle it.

We had one like that about a year ago, The guy had bought an OLD service station and decided to cut up the in ground tanks and pull them in sections. He ended up in two sections himself.

Thanks for the advice but i had no intention at all to open the tank other that unscrewing the top plug and insert a cotton swab impregnated with copper sulfate to touch the wall of the tank.

The tank has been emptied from gasoline and is now 1/2 full of diesel fuel already. There is no remaining smell of gasoline, just that nasty diesel smell !

I've opened the sender hole and checked with a flashlight inside. I saw the bottom of the tank that looked like flaky patterns, can it be electroplated zinc ?