I completed the cleaning portion of sealing a gas tank.  I sealed the cap with food type plastic wrap but the process pressurized the tank and bubbles came out around the cap.  See pictures.  There was also a very noticeable pressure release when I opened the cap with lots of suds.  I'm trying to save the paint but some got under the protective plastic wrap.  Contact was not that long so paint still looks OK.  This is an aluminium tank and also got warm to the touch during the process. The tank is only one gallon. 

 

Will the rust blast have a similar pressuring effect?  Since this is such a small tank, would it be a good idea to use less that the full container of rust remover?  (The tank looks pretty clean inside.)  Does the tank have to be totally dry before using the rust remover?                    

KBS Klean and RustBlast will not harm a fully cured painted surface when used according to the directions. So, in your circumstance, if you get a little bit that leaks out on the exterior of the tank, rinse well with water and you will be fine.

 

Please let us know if that helps and if you have any additional questions.