Sealing a new gas tank or not?
 

Should a new, original-style, third-party gas tank be coated inside prior to installation or not? It looks as if it might be zinc-coated but this doesn't mean anything, it was a cheap tank and a cheap coating might rust just as well. It sure will be painted on the outside but I'm not sure about the inside. Modern gas is also said to be more aggressive than it used to be.

Those who do recommend coating: What to use? Something that's meant for old tanks like POR15 or is there something else (maybe less costly) that can be used on a perfectly clean new tank?

Regards
Martin

KBS coatings makes a good fuel tank sealer. About US$65 + shipping.
I wouldn't use POR15 in a tank.
http://www.kbs-coatings.com/tank-sealers.html

Wow. My first post. I am famous now. Oh well...
My experiences tell me you should not coat it. Some coatings degrade and dissolve. IMO its easier to deal with some rust with filters someday or by flushing [many years in the future on your NEW tank] than it is to try to work around the additional problems you will have when the coating degrades.

I too have had a "treated"..."coated" fuel tank failure and it wasn't simply a leak.
What happened was a bit of the coating got free and found it's way downstream ending up in the carb causing the engine to run lean and burned up a valve .. Ended up with buying a valve job $$$ plus a new tank $$$..

Keep the tank full, reduce the likelihood of rust buildup. :)

I've used epoxy gas tank sealers to good effect. The key is good tank prep and washing it out with acetone.