Author Topic: 1989 BMW R80 build  (Read 390 times)

Offline Karl1989

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Re: 1989 BMW R80 build
« Reply #10 on: Oct 23, 2017, 18:12:56 »
Does anyone have guidance on neutralising the tank after using the acid. I've seen baking soda and water but what type of measurements are we talking and how long to leave in the tank?


Offline jpmobius

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Re: 1989 BMW R80 build
« Reply #11 on: Oct 23, 2017, 18:48:26 »
It depends on how concentrated the original acid solution was and how much of it remains in the tank.  Assuming you pour it out and are only intending to neutralize what's left it will be easy.  The concept is that you are not trying to exactly neutralize a specific quantity of acid, you simply want to neutralize all of it.  That means you merely need to have a surplus of the neutralizing agent to that needed.  Even if you use very concentrated acid, the very small volume left will be easy to overwhelm.  A cup of baking soda (sodium bicarbonate/NaHCO3) in a gallon of warm water should prove to be overkill.  This won't take any significant time as the materials will react pretty much immediately.  Just pour it in, swish it around, and maybe turn on sides and top to make sure it gets into any joints or crevices around the filler neck or any other seams.  Give it a few minutes (just to be sure and have peace of mind) and drain it out.  Rinse with plain water several times and immediately throw in some gas with oil in it and swish to coat everything or fill to the brim with gas.  The freshly etched steel will almost instantly surface rust.  Don't worry about it, just coat it to stop the reaction with the oxygen in the air.  If you are going to paint, you will want the gas out so go heavy on the oil to leave a residue after emptying. 

On a long enough timeline, the survival rate for everyone drops to zero.

1973 RD350 Yamaha build

Online irk miller

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Re: 1989 BMW R80 build
« Reply #12 on: Oct 23, 2017, 18:55:26 »
You don't need to do anything to neutralize phosphoric acid.  Just a rinse with an alcohol/water solution is fine.  On tanks I don't intend to line, follow that with a rinse of 2 stroke fuel mixture, then I run it like normal.  The only time you need to neutralize a phosphoric etch is on aluminum parts.