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Old 02-12-2008, 01:37 PM
oldred oldred is offline
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Obviously you are determined to do this but just as with body work if you do you will in all likelyhood regret it. The problem is that although it will remove the rust you see (actually what you see is NOT rust, it is the already oxidized byproduct of the rusting process which you can not see) it will set in motion a process that will lead to more damage than you have now. Once the acid contaminates the iron (ESPECIALLY iron castings which tend to be somewhat porous) the chemical reaction that starts will be nearly impossible to stop. Some will say you simply need to neutralize the acid, much easier said than done, and while steps to do this will slow the damage it hardly ever stops it completely. The rust solutions both dissolve the oxide on the surface and convert it to a phosphate that tends to stop the rusting process, the Hydrochloric (Muriatic) acid on the other hand will dissolve the oxides but as far as stopping the rusting process it will be like throwing gasoline on a fire! I have battled this for years on mining equipment that was exposed to Sulfuric acid and I can tell you that once the metal is contaminated it can really make a mess. It is not as simple as removing the iron oxides that you can see you must take into account the chemical process that you are about to start, and this is one that you don't want any part of! Do yourself a favor and use Phosphoric acid because it will remove the oxides also but it will start the right chemical reaction that will leave the phosphate coating that will inhibit rust instead of accelerating it. The Phosphoric acid may take a little longer but it is definitely the better way to go, usually the fastest way out of something just leads right back in!
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