Quote:
Originally Posted by Bob Bidonde
I downloaded these gas tank cutaway pictures from the internet. I do not know who these tanks belong to, but the pictures are very informative of the gas tank innards.
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Bob, the two outside pictures posted above are pictures I took if customer's tanks that we have restored.
Quote:
Originally Posted by Keith True
I haven't heard of lye being used for anything in a long time. I'll bet lye would strip the sealer out of a tank.
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It has been our experience that the only thing that will soften (-NOT totally dissolve or strip) tank sealers is Sodium Hydroxide in about a 15-18% solution mixed with water that has been heated to around 200°. Generally soaking the tank for 24-36 hours will allow it to soften the sealer enough where it can be scraped away followed by mediablasting the remaining traces. It is worth noting that this high of a concentration of acid will dissolve soft metals such as solder. Old radiator shops did not use that high of concentration in their cleaning tanks (-general less than 10%) simply because it would dissolve the solder around the tubes to the headers. Unfortunately 10% is not strong enough to soften most sealers.
I also have a theory based on what we have found that it really is not the sealer itself that is affected by the modern fuels. What causes the adhesion problems is where the metal surface was not properly cleaned prior to the new sealer being added. It tends to flake away when the metal under the sealer continues to rust. A great example is the pictures below that show the sealer was applied however the metal was never totally cleaned. Even when organic rust dissolvers are used, it leaves a residue that the tank sealers will not adhere to very well.
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