Combating Costly Corrosion
A magnesium chloride cocktail can destroy a lot more than sheet metal.
JIM WINSOR
EXECUTIVE EDITOR
Highway departments in states where snow and ice are annual winter events are already fighting Old Man Winter. This means laying down tons of corrosive highway chemicals to melt snow and ice in order to make roads safer. If your fleet operates in states where even occasional snow and ice storms bring out the killer chemical spreaders, let me remind you that once vehicles are sprayed with a dose of the stuff, the insidious cancer starts devouring your trucks. And often in places you'll not see until severe damage has been done.
We first reported what can happen in an award-winning feature that appeared in the September 2001 issue of HDT. The worst chemical culprit is liquid magnesium chloride, which was referred to a decade ago as a miracle compound. It is a solution of magnesium and chloride, which lowers the freezing point of water. In fact, some highway departments — mainly in western states — sprayed the roads up to 48 hours before a storm to prevent snow from sticking and ice from forming.
By keeping roads clear with chemicals, highway departments save mega-bucks by reducing the need for plowing, sanding and cindering. The super-blend helps to reduce winter accidents, too. Truckers and the public thought it was a win-win situation because reduced highway salt use (sodium chloride) and calcium chloride means less chemical run-off and roadside pollution.
As we reported, the mag chloride cocktail can work its way onto brake shoes, eating away the shoe table and loosening and cracking the linings. This is called "rust jacking," and it can cut lining life in half and seriously impact brake safety. The potent liquid also attacks metals of all kinds — even some stainless steels — and is noticeable on wheels, rims, electrical wiring, fuel tank straps, frames, trailer landing gear parts and suspension parts.
The best known and least expensive way to reduce damage is by regular and thorough vehicle washing to remove these chemicals. However, washing can be a disposal problem because the wash water runoff is now loaded with road chemicals. If your vehicles are exposed to this stuff, I seriously recommend regular washing, preferably with high pressure. Better yet, do as one New England fleet manager tries to do; drive in heavy rains to get a free rinse.
Now there may be one piece of good news. The Colorado Dept. of Transportation — the leader in mag chloride use, according to the Colorado Motor Carriers Assn. (CMCA) — is altering its blend with the addition of anti-corrosive agents. CDOT says that while the de-icer is still mag chloride-based, the formulation is no more corrosive on aluminum and stainless steel than is sodium chloride. The CMCA says it is getting samples and will test to see if the anticorrosion agents really do what the CDOT is claiming.
In addition, CDOT is saying that it is altering its practice of applying the liquid de-icer up to 48 hours before an expected storm. In past years, truckers have had to drive through the liquid in its purest form for almost two days, seriously saturating their equipment. CDOT is now saying that with the use of new application trucks, the solution can be applied with less lead time. It will take at least this winter and maybe next to find out if the new stuff does what CDOT is claiming. CMCA leaders have their doubts. If it does work, the new formulation could be the basis for other mag chloride states to alter what they're using.
In the meantime, many fleets with only two- and three-year old equipment spread from New England through the Midwest and Rocky Mountain states are finding themselves with big-ticket repair bills. One fleet manager, speaking at the Technology and Maintenance Council (TMC) fall meeting, summed it up this way: "If we don't quickly find a solution through use of better materials and better paints and coatings, we're going to find ourselves back in the repair and repaint business where we were 30 years ago. And we certainly can't afford that."
So, for the near term, high-pressure washing seems to be the best alternative. And for those of you who don't live in the so-called "rust belt states," make sure you wash equipment that is dispatched through these areas in winter months.
