Tuesday, November 1, 2011

Thinking Outside the Rusty Box: Part 2 – Success with a Twist

Back in June of this year (2011), I started evaluating the chelation rust removal process as part of my ongoing restoration efforts on my Boss 302.  Though I entered the experiment as a skeptic, I now have a new-found appreciation for this technology.

I started my evaluation of chelation by making the decision to only evaluate the apparent top-of-the-line products marketed directly to the automotive market as a concentrate.  My reasoning was simple:  Why pay good money to ship a solution of 80% water when I could mix it myself for less?  I stand by this position and maintain that this is the only practical approach to incorporating chelation rust removal effectively and affordably on a larger scale for the hobby automotive or motorcycle restorer. 

In my previous installment, I purposely left out the name of the original product I evaluated until I had a chance to evaluate a second competitive product and report the results. After careful consideration, I have decided to reveal BOTH products with the caveat that I do not exclusively endorse either one.  They have very similar performance characteristics but at the same time, they have their idiosyncrasies as well.  I will try to identify these further as I go. For reference, in each test, I purchased 2 one-gallon jugs of concentrate for evaluation.

The first product I tested is marketed by a company called Ultra One Corporation in Hackettstown, NJ and goes by the name of Ultra One Safest Rust Remover.  Safest Rust Remover is available in one-gallon concentrate (and premix) in gallons jugs and 55-gallon drums.  Please reference my original chelation test here for more information on the Ultra One Safest Rust Remover concentrate:

The second product I tested, and featured in this installment, is marketed by a company called Rust Depot in Horseheads, NY and goes by the name of Esprit Performance Rust Remover.   Esprit Performance Rust Remover is available as a concentrate only in quantities from 16 ounce bottles to 55-gallon drums.

The Esprit Performance product is also mixed at 4:1 (4 parts distilled water to 1 part concentrate) just like the Ultra One, but it has the distinction of being clear and colorless in the jug, where the Ultra One was pee-yellow.  Esprit also touts their product as having an added “metal cleaner” in the mix to help remove light oils, grease and dirt.  This, in my opinion, is not much of an attraction since I believe you should start with a cleaned surface.

Application of the Esprit product is the same as the Ultra One with either constant spray/cascade or complete immersion.  Since the spray application was the method of choice for me, I used the same equipment I used in my first test to apply the Esprit solution, but I did drop a few pieces into the solution just so I could see how effective the immersion technique would be.  I targeted the inner rear quarter panel of my Boss for this test since the rust in this area was about equivalent to the roof rust I removed with the Ultra One, so I felt I had as close to an apples-to-apples comparison as I could get.

One change I attempted to make was to heat the chelant with a 1500W engine heater plumbed in a constant bypass loop right off the circulation pump.  This would allow me to regulate peak flow at the sprayer by simply diverting any excess flow through the heater circuit and back into the tank, similar to a modern returnless fuel system.  This makes for a much easier job for the pump (no dead-heading) and still allows for simple plumbing to the heater.  The result:  FAIL!  Didn’t work worth snot and proved to be a total waste of time for several reasons.  Most influential was the slow thermal transfer of the heater to the fluid and the rapid heat loss of the fluid to the air as a function of spraying (atomizing) and wetting a rather large, cool surface with a thin layer of fluid.  In short, I need to look at an immersion-type heater to make this work.  Another trip to Tractor Supply…….

Because the scale of the project was considerably smaller than the roof treatment, I was able to use a small cement mixing pan as my containment pan and a fan head garden sprayer for delivery.  Having learned my lesson about fluid loss based on my earlier trials, I elevated the pan on a quartet of plastic 5-gallon buckets to minimize splash and keep everything closer to the work area. 

Satisfied that everything was secure and ready to work, I set the process in motion and adjusted the spray head to provide the maximum coverage possible without spraying expensive chelant all over creation.  After a few short hours, the results were quite impressive.  Rust was definitely being removed but I started to notice a few new characteristics I had not seen with the Ultra One product.  First, all of the plastic, rubber and vinyl parts and some of the painted parts that come into contact with the Esprit chelant develop a glossy, slightly sticky surface. 

Also, over time, the edges of the wetted areas develop a copper-like residue just outside of the grey/black film that develops as part of the process.  I am pretty sure this is a byproduct of the metallic ions leeched off of the brass/bronze valve & hose fittings I use in the plumbing scheme.  No big deal as it scrubs off rather easily with scotch brite pads, but interesting nonetheless.

I am happy to say the Esprit Performance Rust Remover works well.  I admit that it worked a fair bit slower than my June test of the Ultra One product, but this is mostly attributed to the fact that the chelant is forced to operate at about 70°F at this time of year in my shop given that my heating approach failed to function as intended.  A clear lesson I have learned is that rust removal time (a.k.a. chelant effectiveness) is drastically improved with increases in temperature, with my defacto target temperature being about 120°F.  Even though both product suppliers indicate the chelant can be heated to a higher working temp, I think the benefits vs. risks of going any higher than 120°F are such that it makes no practical sense to aspire to a higher temperature target.

So, with the test results from both the Safest Rust Remover and Esprit Performance Rust Remover in hand, what’s the verdict?  Actually, the answer is a bit complicated. 

1.     First and foremost, BOTH products work as advertised.  I remain absolutely convinced that the ONLY way to purchase chelant for any project that will require a volume exceeding ½ gallon is in concentrated form.  As such, this tends to steer a consumer to one of these two suppliers based on my experience and research. 

2.    Unfortunately, the specter of cost forges the point of my biggest complaint between the two suppliers.  The absolute straight skinny on cost is that Ultra One commands a comparative “King’s Ransom” for their gallon of concentrate at $100 US/gallon!  Rust Depot, on the other hand, commands “only” $62.50 US/gallon for what is functionally the same product.  Add the usual shipping premium that most any carrier applies and you are not talking about insignificant differences in cost.  Ouch!

3.    Performance of both products is quite good.  Equivalent for the most part, in fact.  The chelation process doesn’t give a crap at how nasty the rust is that it is being asked to remove.  As long as you keep delivering viable (e.g., non-saturated) chelant to the rusted surface, this stuff keeps eating it until there is absolutely no rust left.  All this without damaging the parent metal.  Think of chelation as “targeted rust removal”.  A “smart bomb” for rust, if you will.  In my experience, the speed of rust removal is directly proportional to temperature and I need to come up with a much better method of heating the chelant.  As development in this area continues, I will document it here.

4.    Both products react rather aggressively to leaded body filler and galvanized metals (particularly zinc I think).  This makes perfect sense as I think about what chelants are designed to do from a medical perspective.  They capture metallic ions in the blood and allow them to be excreted from the body.  Our old Mustangs use genuine lead body filler at the top of the A and C pillars where the roof seams are located.  As such, the chelant eats rather heavily into this material as it goes about removing surrounding rust.  Generally, this isn’t a big deal, but beware the effect this may have on the used chelant solution and how you treat and dispose of it.  Neither supplier had ever heard of or experienced this phenomenon so I was on my own.

5.    Customer service is one of those things that mean different things to different people.  I absolute abhor crappy customer service and I am of the opinion that the advent of the “internet-based” business has allowed the degradation in customer service to accelerate at an unnatural rate.  Fortunately, both suppliers proved somewhat available for questions and both suppliers were very familiar with the hands-on application of their product.  But without being too pointed, I spent less and got more.  I’ll leave it at that.

6.    Clean-up after treatment is one place where I found the two products diverged significantly.  As I mentioned before, the Esprit Performance remover left all non-metallic parts with a slightly sticky, glossy residue and areas where chelant was allowed to run and dry required a bit of scrubbing to get clean.  I did not experience either of these conditions with the Ultra One product and I expect this may be due to base formulation differences, like the addition of the detergents in the Esprit formulation.  For me, I would just as soon see Esprit do away with the detergents and lower the cost even more…..at which point their product would be a double-tough act to follow.

In summary, I am sold on the process.  However, I am convinced there is plenty of room to improve the application of chelation to the automotive restoration process.  Fortunately, I have several ideas I plan to test and report on this blog in the hope that my fellow restoration hobbyists can benefit.  Also, I have found one more chelation product that may just prove to be the silver bullet for most adventurous enthusiasts that want to try the chelation process for rust removal but either can’t or don’t want to invest in the equipment to spray and recover liquid chelant.  Also, I have a request (by a group of individuals, NOT a manufacturer) to review one of the most popular premixed, commercially available chelation solutions as well.  So there’s plenty more to come.
Here is my attempt at heating the chelant.  I used an inverted 1500W engine heater setup in bypass right out of the pump.  Looked nice and clean and worked for CRAP!  I'll have to come up with something else.....
Chelant is in the catch basin and the system is ready to go.  Note how clear the fluid is in the beginning.

With the flow regulated by the amount of fluid I allow to bypass through the heater, I set the spray head to cover the rusted area as completely as possible.

I managed to capture the bulk of the overflow quite successfully using this simple concrete mixing pan.  The foaming you see here is a result of the returned fluid agitation as it splashes into the recovery basin.  Within an hour, the chelant starts to take on the distinctive "rusty water" color seen here.

The next series of photos are intended to show the progression of the rust removal process over time.  The total spray time from start to finish is approximately 10 hours.


  1. Sven - great investigative work. Thomas Edison would be proud :) I wonder if one of those tankless hot water heaters would work as a pre-heater for the solution? 120 deg sounds like something these things could produce. Not sure if they would have the duty cycle to handle continuous heating but it wouldn't be a big deal to put a timer in the loop. I agree that any hotter than that and bad things might start happening.


    I recall as a youth, there was an outfit in my town that 'tanked' entire cars for rust removal. I hadn't thought about it until just now but I'm curious if this might have been a similar process. That quarter panel conversion is incredible to watch. Flame on!


  2. RJ, This has definitely been an interesting adventure. It's innteresting you mention tankless water heaters. I actually have one inmy house and was one of my first thoughts. Problem is cost. Very expensive for this sort of thing and the best units are gas fired.

    I remember when chemically "dipping" a car was all the rage (this was inno way relatedtochelation). Unfortunately every single person I know that used that process has regreted they ever did it. Lesson learned.

  3. Sven, I know when we lived in Sweden, they had little tankless electric water heaters under the bathroom sink. Very compact. Always wanted to gut one to see what made it tick but unfortunately they never failed so there was little excuse for investigative disassembly.

    I was pondering this process today while at work. In your opinion, which process do you favor - sand blasting or chelation? Or does each have its place? Would be interesting to see the grain structure under a microscope. Chelation is probably superior for panels as you don't have the warping worries. For heavily rusted suspension pieces, sand blasting may given a better end result. Curious to hear your thoughts on that.

  4. RJ,

    I remember the same little heaters when visiting my family in Germany while growing up. I think they have been on to that technology for over 50 years! The electric versions I have seen here in the US seem to all run very high amp loads, even on 220v, so I have really not moved in that direction.

    As for favoring sand blasting over chelation or vice versa, I think each process has it's place for sure. Sand blasting is really the only way to deal with a lot of crusty gunk and is hard to beat on heavier structures that will be painted later on. It provides excellent "tooth" for fillers or coatings and it's fast and relatively inexpensive. Sand blasting is extremely versatile in that various surfaces can be achieved by simple grit selection and drive pressure setting.

    Chelation, on the other hand, is pretty much a rust removal process only and is my choice for on surfaces that I prefer not to abrade as heavily as sand blasting will or on any delicate surfaces (of which I consider most external "finish" surfaces. I prefer to follow up chelation with a manual surface prep to avoid doing anything too aggresive. Consider them both viable bullets in the gun, but be selective as to the target.

  5. Agreed - well stated!

    As I recall now, the 'tanked' process was some sort of acid dipping wasn't it? I seem to remember racers 'dipping' bodies to lighten them. I can only imagine the damage caused by acid trapped in all the myriads of cracks and crevices that are a uni-body car :/


  6. Absolutely correct. "Acid dipped" bodies were a rather sneaky way to take weight out of "body-in-white" factory race cars. Imagine the weight savings if just .003-.004" of material thickness was taken off every single surface of a complete chassis.

    However, as you clearly identified, the acid solution becomes trapped between flanges and in seams and cannot be completely removed with a dip-rinse. 25 years later and those same cars were often devastated with rust and other structural damage. Not a good plan.....

  7. Excellent expose' on rust treatment. I do wonder how well the chemical can be removed from body seams as you stated so there isn't a surprise in either rust reappearing or the chemicals leeching out and ruining a paint job. Nonetheless, thanks for all your extensive and thorough research.

  8. Very interesting stuff Sven. Thanks for the write-up!

  9. Dennis,

    This is exactly the problem with acid dipping. The beauty of chelation is that once it's dry, you're pretty much good to go! I make a habit of rinsing all surfaces with degreaser no matter what, and have yet to see any issue.

  10. Thanks Alex! There is more on this subject to come.

  11. I came accros this post today and i'm very impressed with your skill and accomplishments. I'm in the early stages of restoring a 68 fastback in southern indiana and I've been dabbling with this chelation rust removal process for the last 11 months. I've been on a lean budget and opioned to use farm grade mollases and water mix in my process. During the summer months I've derusted fenders, hoods, and doors by submerging them in a small snapset pool. Now that the weathers gettin colder I'm going to have to move this project to my attached indoor garage. The mosasses mix has a little bit of a pungent smell that I don't want circulating through my home so I've been intending to switch to circulating shower system using the Rust Depot product. I have a question I hope you can help me with. After you've removed the rust, what brand of metal prep have you been using to prevent rust from flashing back? What is your proceedure for treating the metal until your applying the epoxy? I've been de-rusting my metal with the mollasses mix and rinsing it with hot water once all of the rust is gone. I've then been quickly drying the metal and treating it with "Prep & Ready" (Metal Ready) and after keeping it wet for 15 minutes and then rinsing it off. The problem I'm having is that my newly clean panel wants to flash rust in areas before I can get it all dried off. From your photo's you appear to have mastered the process I've long been looking for. Any assistance is greatly appreciated!


  12. Lee,

    Thanks for the comment. I will do my best to answer your questions. You are actually dealing with what might best be described as the "original" chelation process. A roughly 9:1 mix of mollases and water make a very effective (albeit kinda smelly) chelant solution for relatively little money. Unfortunately, it seems this mixture doesn't lend itself to recirculating use so if you can't submerge the part, you're outta luck as I'm sure you've discovered as well.

    Flash rust is a real pain to try to avoid and something I chase constantly. Two "secret" things I have learned the hard way are: always use either deionized or distilled water for rinse and always use an acid-based metal prep before coating.

    The lesson here is that tap water or (worse yet) well water is so full of metallic ions, there is absolutely no way to prevent flash rusting. The latest thing I have been doing is to mix a weak solution of water and phosphoric acid as a rinse followed up by a proper phosphoric metal prep spray that I only leave on for a few minutes then wipe off with a clean cotton cloth. This gives me a nice, clean, phosphatized surface that only requires a slight scuff and degrease before primer. I do not believe in priming directly over the phosphate as some have advocated so I will scrub and degrease no matter what. So far, so good but I am always trying to refine my technique, and anything I learn I share here.

    I am working on more tips and application techniques for the chelation process that might prove valuable when you start using commercial chelants, so keep checking back or shoot me a note if there is something more specific.

  13. Amazing work! Your attention to detail just is amazing.

  14. Thanks James! You are too kind......

  15. I was about to mention the mollases treatment I have heard of (never tried it myslef) as it sounds like a similar process to the chelation process... then I saw the post from anonymous!!! Thoroughly interesting read as always Sven... well done!

  16. Thanks Mike! As time goes on, I may do a mollasses-chelation spot on here just to show that it too can be very effective at rust removal from intricate or hard-to-reach areas.

  17. Your quality of work is astounding and seeing what you've accomplished has certainly been an inspiration for me to continue with my own restoration project. I've worked as an estimator and project manager in a sheet metal fabrication shop and I have to say that your welding skills match the very best as the welders that did this daily for a living. I greatly appreciate your response in answering some of my questions concerning you processes. You've saved me a great deal of time with experimentation which often results in learning the hard way. I've researched a great deal on my own and I'm convinced that your totally on track with these cutting edge restoration "rust rid" techniques. I was somewhat surprised when you mentioned that the molasses treatment would not work in a re-circulating shower system. I would have thought that it would have worked. I decided last summer that I was switching to the commercial concentrate, to avoid the odor, when I switch to the circulating bath indoors. I now have the rotisserie, the pumps, and a catch basin and I'm nearly ready to start. I was also thinking of trying to flood the inner rocker panels with the Chelating fluid by regulating a flow by pumping it in a hole I'll create in one end and recovering it though another hole and into the catch basin at the other end. I was really hoping that you could elaborate a little more on the phosphoric acid treatments that you're performing. Are you using a "Prep & Etch" type product with a 1:4 (acid to water) mix ratio, wetting the metal for 10-15 minutes, dry toweling it off, then re-scuffing the metal and cleaning with your PPG grease and wax remover just before priming? I only ask because I have metal that's going to need treating very shortly.
    Any assistance you can offer is greatly appreciated.


  18. Lee,
    You are entirely too kind and I appreciate your compliments very much. I am truly thrilled that something on my blog has been of value to you. That was the outcome I had hoped for in presenting my experiences in the first place.
    My experience with the molasses chelation process in a sprayed application is the molasses develops a sticky residue the more aerated the solution becomes and really trashes up the recirculation equipment in fairly short order. I really don’t know what the exact root cause of this has been, but the increase in smell alone was plenty for me to not do that anymore. I much prefer the soaking bath application method and it seems quite a bit more effective and less smelly overall. Of course, this may not be the case for everyone, so I remind you that this is only my experience, and limited at that.

    I really like your idea about treating the inside of the rockers with the flood technique you describe. It might be worth using clean water to test the setup and flush the debris from inside the rocker before committing your expensive chelant to the job. I can’t emphasize enough the importance of starting with everything as clean as you can so that all that remains to contend with is the rust itself.
    As for the phosphoric acid treatment I use, I have found the Kleen Strip Prep & Etch product available at most big box stores to work well for a reasonable cost. As a concentrate, it gives me the ability to vary the strength of the acidic solution as I choose. I play with ratios between 3:1 and 4:1 distilled water to acid and tend to favor the slightly stronger solution following a chelation process. Otherwise, you have my process nailed down exactly. When I scuff the phosphate surface with scotch brite, I soak it in PPG DX-330 and only scrub until the loos white powdery phosphate is removed. Then I wipe it down with a clean, lint-free rag to clean off the abrasive debris and follow up with another swabbing of degreaser that I let air dry. From there, I use the recommended prep for the finish I’m applying and so far, I have had excellent results.
    I wish you all the best and hope this information helps in your project.


  19. This comment has been removed by a blog administrator.

  20. Arlie,

    Thanks for checking in. I looked over the link you provided and am a bit surprised that I never ran across this company during my research (which I _thought_ was rather extensive). In any case, it looks like they offer competitive product at almost exactly the same price points to the Esprit Performance products I most recently used. In fact, now that I look at it, this company is in the same area code as the Esprit folks AND they are using a lot of the same photographs! Starts to make me wonder if they aren't one-and-the-same or close anyway.

    Looking over the information on their site seems to show many of the same things I discovered on my own to be true and there is some interesting car restoration examples as well. Might just have to give them a try as well. It would sure be nice if there was an easy way to figure out if the two companies are related.



  21. I thought exactly the same thing. Of course re-branding is common. This company offers their product in generic form for that purpose (see their "distributor" link). Your documentation of success will help a lot of people.

    I'm just starting a similar project. Glad I could chime in.

  22. First, I want to apologize to Arlie for having to delete the original post. Without getting into a bunch of detail, I have chosen to not allow navigating to a site link included in the message from my blog. I would have preferred to simply delete the link and leave the rest of the message, but no such luck.

    For clarification's sake, I remain committed to my product recommendations based on my experience and use and do not, at this time, make any other chelant product and/or supplier endorsements or recommendations. I apologize for any inconvenience.