Denny,
I am pleased that you have witnessed the results. We just need to help 'fine tune' your process. I will try to answer your questions in order.
Light surface rust should be removed much quicker than 24 hours. Depending upon strength of the mixture and the ambient temperature, usually a matter of a few hours @ the most. This would be only w/ the concentrate diluted 10:1. This formulation depends on the distilled or softened water to work efficiently. This is another example of 'more is not better', meaning a more concentrated mixture. The larger quantity of water will help to hold more of the derusted by-products in solution, thus keeping the solution active instead of becoming saturated, and thus, useless. So be sure to use the water and mix 10:1!
I mentioned distilled or softened water. These are ideal as it allows the solution to absorb the most derusted by-product. It will work w/ tap water, however it is the quantity of minerals that matters, the fewer minerals, the better it works.
Concerning the small sheet metal panels. The mixture has to be 10:1. At that mixture, there should not be fresh metal removal unless the part is left in way too long. The benefit to your experimentation is that now you can see how fast and effective the D-Rust-It is! Just try shorter times in the proper mix, and continue to monitor their progress. Every real world situation is different. One person's interpretation of light surface rust, may not be the same as another's.
Regarding D-Rust-It trapped in the door frame where the outer skin folds around it. The best approach is to rinse the part thoroughly for a longer period of time, as opposed to a completely exposed surface. There will be a very thin protective layer built up on the surface of the metal after treatment w/ D-Rust-It. This allows you to rinse the part for a very long time before any flash rusting would occur. This way you can remove vitually all of the D-Rust-It solution. Obviously, it is best to rinse the part immediately after treatment to prevent the solution from drying on to the part first. On our website you will find a picture of the PTO pulley on my 1928 case Model 'L' tractor. After D-Rusting, we intentionally left it outside in the elements to find out when it would begin to flash rust. After three days w/ dew overnight and rain another night, and part of the day, there has been no flash rusting. Worst case, is that a small, highly diluted mixture could dry inside the fold, but it will be virtually inactive when dry. If by chance it does re-emulsify w/ some rain water, the very weak mixture may actually prevent further rusting due to the protective layer formed afterward.
I hope this helps. If you have any further questions, don't hesitate to contact me or Howard.
Regards, Lee
