For best results, use at room temperature (20°C) or above
Metal Rescue™ works optimally at room temperature (20°C) and above, so it may require heating in cold temperatures. Nearly all of the photos and testimonials found on this website were of metal parts that were de-rusted at room temperature. However, if you are trying to speed up the rust removal process, Metal Rescue will continue to work faster up to a temperature of 70°C. Remember, Metal Rescue is a water-based liquid and therefore operates differently than an acid or other traditional rust remover. A useful analogy is of very soiled and dirty dishes. It would be very difficult to remove heavy grease or sticky substances in cold soapy dish water compared to warm soapy dish water. Because Metal Rescue is water-based it functions in a similar way. Please note that this analogy is meant only as an analogy. Metal Rescue does not have to be heated up to work-but it does require room temperature or above.
Metal Rescue can be used over and over until it turns jet black and stops working
Keep Metal Rescue liquid covered when in use or in a closed container when not in use to prevent evaporation from occurring. If performance slows down prior to liquid turning completely black, evaporation may have occurred. In this case, a small amount of clean water may be needed to bring the solution back to the correct mixture. The best way to know how much water is needed is to mark the soaking container you are working with at the liquid level, prior to placing parts inside.
After Metal Rescue has de-rusted the parts, remove parts and make sure that liquid level is the same
If not, then you will need to add enough water to bring the solution back to the mark line. Please note that this is seldom needed. It typically would only occur if you are working with Metal Rescue in hot outdoor conditions. To avoid evaporation, keep a cover over the soaking container and pour Metal Rescue back into a closed container or original bottle/pail after usage. 5 litres of Metal Rescue should be able to de-rust approximately 300 grams of pure rust!
Do parts have to be completely clean before using Metal Rescue?
No. Metal Rescue will penetrate oil and dirt. However, it’s recommended to pre-clean your parts before applying Metal Rescue. Detergents are more economical and are designed to remove various contaminants. This will also speed up the process of rust removal and extend the life of the Metal Rescue. Cosmoline, heavy greases, and similar materials should be removed prior to de-rusting.
What will Metal Rescue remove?
Metal Rescue will remove iron oxide (rust) from ferrous based substrates in 5 minutes to 24 hours depending on the degree and age of the rust. It will remove zinc phosphate, bluing, browning, and other oxide finishes in about 20 – 40 minutes immersion time. It also brightens copper and copper based alloys such as brass and bronze. For metals with questionable finishes, we recommend you test a small portion of the metal in Metal Rescue prior to full submersion.
Restoring a rusty gas tank with Metal Rescue
Metal Rescue is an excellent rust remover for gas tanks of any type. One question we commonly receive is what to do after de-rusting a gas tank with Metal Rescue. Many mechanics and hobbyist are used to using a cream coating of some type to seal the gas tank. This cream coating is often used for two primary reasons:
- To prevent flash rusting or re-rusting of the gas tank and
- To fill in any pin holes or holes that were caused by the rust.
However, we do not recommend using a tank liner or cream coating unless you have no other alternative. If there are pin holes in the gas tank, after removing the rust with Metal Rescue, we recommend welding or brazing the tank from the outside. If you do use a tank liner/coating, please read carefully the instructions on the cream sealer coating. Some of these coatings actually require rust to be present in order to allow it to bond properly. This is common with some of the “paint over rust” or rust converter products. From our perspective, we would never want to restore a vehicle and leave rust of any type on the metal. If you do not follow some of the paint over rust product instructions carefully you may see the rust creeping back through the coating which, of course, would not be a good thing. Our philosophy is always to remove the rust completely in a safe, clean and easy way and get it dry and coated with Dry Coat™ Rust Preventative. Regarding the concern of flash rusting, typically, this is not a concern when using Metal Rescue since Metal Rescue is attracted only to the iron oxide and not the metal substrate. For complete instructions on how to de-rust a gas tank using Metal Rescue please download the PDF here.
How to use on painted surfaces
Metal Rescue will not remove or harm the vast majority of paint coatings. However, if there is a layer of rust under the paint some of the paint coating will be lost as Metal Rescue removes the rust and therefore the paint on top of the rust. Also, some paints (and inks) may use iron oxide pigments (usually orange or red). Since Metal Rescue has been engineered to remove iron oxide, it may dissolve the pigment in these types of paints. It is always best to test on a small section or hidden area prior to use.