I LOVE this stuff. The time it saves me, and the results it provides are FAR beyond what I had hoped for. If you are dealing with parts small enough to fit in a container for complete immersion, and you require a bare metal result, this may be the best choice.
If you work on cars, and like things to look good when you are done, or are trying to reuse existing parts, then this product is a very cost effective must have. I bought a gallon when I first started work on the Bonneville BAD CAT Jaguar project.
Virtually everything I removed from the car was rusted. While not a restoration project, in order to maintain the ‘PRO’ category, all the lighting etc. must function. So, all the brackets, nuts bolts screws must either be replaced, or made operable. I was a little (lot) skeptical of the claims to ‘dissolve’ rust, what with all the ‘rust convertors’ and ‘rust encapsulators’ available on the market. But, for under $40 from Eastwood, I thought I didn’t have much to loose, so I ordered a gallon. This turned out to be one of the best purchases I have ever made.
Quite a while back, I stumbled upon a bunch of 1″ bolts at my favorite scrap yard. As I had been planning on building some screw jacks to use on the frame jig/hoist, I thought these would be perfect for the purpose. Getting close to actually needing them, it was time to get them cleaned up. Here’s a couple ‘before’ pictures so you will understand what they started out like. Apart from having chased the threads with a tap, they are as found. As you can see, kicking around a scrap yard, banged about by other steel and iron and exposure to the elements has done them no favours.
But, now knowing just how well this stuff works, I had no concerns about making them good for this purpose. I have used several 1 gallon ‘snap lid’ tubs to use as dip tanks for the various chemicals I use to treat or clean various things I use an old stainless steel deep fryer basket to contain the items to dip into the soutions. With all the ‘tanks’ the same size, I can readily transfer items between tanks with minimal direct contact with the solutions. The severity of the rust will determine how long you need to leave the item soaking. Anything from a few hours, to a few days may be required. The process can be accelerated by brushing off the rough stuff so that the solution can get into subsequent layers. Here’s the basket just out of the tank with some of those rusted bolts. The difference is remarkably evident.
Apart from the obvious benefit of not converting, but REMOVING the rust from parts, no intervention is required. Just submerge and wait, I does help accellerate the process to slosh the parts around every now and then if there is a build up of rust. This allows the softened and loosened rust debris to fall away accellerating the process. Your time can be spent continuing to work on what ever that project is. You can also eliminate the time standing at your wire wheel cleaning up parts, not to mention the occasional brushing you fingers will often incure.
A somewhat surprising characteristic of this solution is that it DOES NOT remove paint. I pulled one of the rusted nuts out of the tank early to grab a picture, which clearly shows the paint previously concealed by the layer of rust, completely intact. The same is true for plastic components, which can be safely immersed in the solution. I found this aspect a perfect solution for the headlight retaining/adjustment brackets. No amount of time in the tumbler would get into some of the tight corners or the pitting in the brackets.
An overnight bath in this stuff, made them look like new. Here are before and after images of the adjusters. The before is after roughly 48 hours in the tumbler. You can see the pitting caused by some heavy rust remains. The plastic is completely unaffected by the solution
After the parts come out of the solution, you should run them through a quick rinse in water, to remove the chemical contaminants, then a bath in metal wash to stop flash rusting, and ready the parts for painting, plating or what ever else you have up your sleeve.
I’ve cleaned a couple hundred various parts with the original gallon of solution, with very little loss using this method. Keeping the lid on the tank when not in use, and placing the lid over the tank when I’ve got a batch in the tank keeps the evaporation to a minimum.
Naturally, all that removed rust had to go somewhere. So, when the solution was nearing black, with substantial sediment on the bottom of the tank, I decided it was time to clean things up bit. Passing the solution through a funnel, with a cone coffee filter in it, did the trick nicely. I had to swap out filters a few times as they plugged up with crud and sludge pretty quickly. But, after a few passes through the filter, the solution and tank are in pretty good shape again and ready to go.
UPDATE: A few observations and discoveries of my own, and as a result of comments from others..
FLASH RUST is a real concern after anything has been derusted. RUST DISSOLVER, and several other similar products, are in fact a water based product. While I have tried a few creative solutions as have others, the transition from wet metal fresh out of the rust dissolver, to DRY rust free metal, is a little challenging. The problem is, as you know, combine water, iron and oxygen and you create RUST. A few, myself included, have tried wiping items down with lacquer thinners, thinking the fast evaporation of the thinners would solve the problem. No such luck. While this does remove traces of chemical contaminations, making the items clean for painting, it have minimal impact on flash rusting.
Perhaps because the thinner doesn’t mix with the water base is the reason. In which case, perhaps some isopropyl alcohol, which does mix, and evaporates clean would solve the problem. I haven’t tried this yet, but have some hopes. What I HAVE found is that using a metal wash, preferably designed to inhibit flash rusting gives you a shot at beating the flash rust. In my case, as most of my items are dipped completely into solutions, I have submerged things for several minutes, then towel dried the items immediately on removal. Interestingly, I found that a quick slosh in metal wash wasn’t enough. I had to let it soak for a bit. Perhaps a little scrubbing with a brush would improve the results. Despite all this, I found that when I left a couple of towel dried metal pieces overlapped, which slowed the air drying between the pieces, they still showed minor signs of flash rust. A quick brushing or scuffing with a scotch brite pad cleaned it up.. Perhaps a more complete drying by using a blow gun, or even a heat gun, would finalize the transition.
BRUSH ON coatings of Rust Dissolver on the surface of items, even covered with plastic to impede drying, will NOT likely produce the desired results, and may in fact worsen the situation. The product has been tried simply brushed on to the surface of an engine block, and onto a floor pan. While it does start to disolve the rust, because it is only a coating, rather than submerged, it quickly enters the Air / Moisture / Iron ratio where it starts creating rust.
Again, RUST DISSOLVER is a water based product. The GEL version MAY solve this problem, although we have not tried it, nor heard from anyone who has.
Northern Tools markets a product called Evapo-Rust in 5 gallon pails for under $80. While I have not tried this product, it appears to be essentially the same thing for a lower price. If you try it, let us know how it works.
PHOSPHORIC ACID SOLUTIONS
Phosphoric acid is an organic acid, which reacts with and dissolves rust, interestingly as it dries, it leaves a ‘zinc phosphate’ residue/coating behind. This zinc phosphate coating is as you would expect, bonded or ‘etched’ into the metal surface. On easy to access surfaces, you can reduce product consumption and speed results by using a scotch abrasive pad to scuff the moistened Thus, the bond between it and the metal is much the same as when using a self etching primer. The resulting finish is a light grey primer like finish. Using basic metal washing and paint prep techniques it can be primed and painted over with tremendous adhesion results. Or, you can choose to scuff/sand off the finish to go to more conventional metal finishing methods. Several companies market similar products all based on phosphoric acid, with various additives to provide different results for the intended application.
The great benefit of this type of product is its ability to get into normally inaccessible areas and seams. I have sprayed it into door cavities and allowed it to thoroughly saturate and soak between metal layers to dissolve rust within and provide a level of protection until refinishing or various sealing options are undertaken. I have had tremendous success spraying within wheel wells prior to touch up painting and undercoating. In fact, I even did the under side of a truck that had never been undercoated. After a couple applications, I washed and undercoated and an automotive shop owner questioned his own memory of what the truck appeared like, feeling initially it was a rust bucket, later stating how good it looked and he could not remember why he thought otherwise. If you want to do something like this, pick a cool day, to lengthen the dry time. The longer it remains moist, the longer it works.
There is a ‘slight’ risk of Hydrogen embrittlement when using this rust remover. Bake de-rusted parts at 400 degrees F. for 3 hours if the minimal amount of hydrogen embrittlement is a concern.
Cloverdales ‘ClovaClean‘ product is a “Phosphoric Acid’ based cleaning liquid. In addition to its phosphoric acid base, it has detergents and cutting agents. In Canada, you should be able to locate a Cloverdale store near you. ClovaClean is very reasonably priced, making it a great option for those North of the border Because of the reduced costs by eliminating shipping costs, it becomes extremely practical for larger areas. You can use a pistol grip spray bottle, or a pump tank type garden sprayer to apply the solution to large areas. MAKE CERTAIN you clean your applicator after use by flushing completely with water. Remember, while not an aggressive acid, it is an acid and will gradually deteriorate your sprayer. Wear at least basic hand, eye protection when using as it does have a bite when in contact with skin, and even more so with eyes.
EASTWOOD FAST ETCH
Eastwoods ‘Fast Etch’ product is a “Phosphoric Acid’ based rust removal liquid. Eastwood thoroughly researches and tests their products. They will happily ship this product to you, but it can considerably increase the end cost to you, especially if not located in the USA.
I have been led to believe that Home Depot carries a similar product, but I have been unable to locate it in any of the Canadian stores. You may have success finding it in USA locations.
If you are still having difficulty finding a phosphoric acid based product, check a concrete provider or finishing shop. Phosphoric acid is commonly used to clean concrete to aid it bonding when pouring new concrete adjacent.
NOTE: I have no affiliation with Eastwood, Cloverdale, Northern Tools or any other company referred to in this article, and have not been compensated for this ‘review’