Is this common with certain brands?  A friend of mine bought an alum trailer and had the same thing, she cleaned the trailer out with a hose every time, pulled the mats.. stored the trailer over the winter and when she pulled the mats, there were pits to where she could see through the floor.

Alum floors are one reason I won't buy an all alum trailer.  I like Dream Coach.. I think they are all alum with a wood/rumber floor choice. 

I usually buy a composite, steel/alum to get the features I want, fiberglass roof with a wood or rumber floor. I don't like that the roof gets hot without insulation.  My friend had an uninsulated trailer and when we would unload after a trip on a sunny day, even with the windows all open, vents, too.. the horses were always hot.. esp if we had to stop for an accident or construction.

I would love if all-alum trailer companies would offer the options of having fiberglass and lumber.

Jbsny

Are you sure the pitting is from the inside out??

You didn't post where you are from...so the next question is...

Have you done a thorough examination of the underside of the trailer??...could you be looking at an exterior corrosion event??

I am from Ms. and believe me, one FLAKE of snow and the entire state shuts down!!! Trailer has never been pulled in snow or ice, so I don't think road salt is the cause!

I don't want to say the brand until I talk to the company and see if they are going to honor the warranty.

Pitting corrosion

Corrosion of aluminum in the passive range is localized, usually manifested by random formation of pits. The pitting potential principle establishes the conditions under which metals in the passive state are subject to corrosion by pitting.

For aluminum, pitting corrosion is most commonly produced by halide ions, of which chloride (Cl ^-) is the most frequently encountered in service. Pitting of aluminum in halide solutions open to the air occurs because, in the presence of oxygen, the metal is readily polarized to its pitting potential.

Generally, aluminum does not develop pitting in aerated solutions of most nonhalide salts because its pitting potential in these solutions is considerably more noble (cathodic) than in halide solutions and it is not polarized to these potentials in normal service.

So in MS, how close are you to salt water...such as the Gulf??

You might also see if your unit is subject to stray electrical activity...

CushionEZ Clean is now in California....Protect your floor and save your back.

 And here I thought I would never use any of those college physics courses dealing with the structures of matter...

All you wanted to know about Corrosion on Aluminum alloys...

Effects of Composition and Microstructure on Corrosion

1xxx Wrought Alloys. Wrought aluminums of the 1xxx series conform to composition specifications that set maximum individual, combined, and total contents for several elements present as natural impurities in the smelter - grade or refined aluminum used to produce these products.

Corrosion resistance of all 1xxx compositions is very high, but under many conditions, it decreases slightly with increasing alloy content. Iron, silicon and copper are the elements present in the largest percentages. The copper and part of the silicon are in solid solution.

2xxx wrought alloys and 2xxx casting alloys, in which copper is the mayor alloying element, are less resistant to corrosion than alloys of other series, which contain much lower amounts of copper.

Alloys of this type were the first heat-treatable high-strength aluminum base materials and have been used for more than 75 years in structural applications, particularly in aircraft and aerospace applications. Much of the thin sheet made of these alloys is produced as an alclad composite, but thicker sheet and other products in many applications require no protective cladding.

Electrochemical effects on corrosion can be stronger in these alloys than in alloys of many other types because of two factors: greater change in electrode potential with variations in amount of copper in solid solution and, under some conditions, the presence of no uniformities in solid solution concentration. However, that general resistance to corrosion decreases with increasing copper content is not primarily attributable to these solid-solution or second phase solution-potential relationships, but to galvanic cells created by formation of minute copper particles or films deposited on the alloy surface as a result of corrosion.

2xxx Wrought Alloys Containing Lithium. Lithium additions decrease the density and increase the elastic modulus of aluminum alloys, making aluminum-lithium alloys good candidates for replacing the existing high-strength alloys, primarily in aerospace applications.

3xxx Wrought Alloys. Wrought alloys of the 3xxx series (aluminum-manganese and aluminum-manganese-magnesium) have very high resistance to corrosion. The manganese is present in the aluminum solid solution, in submicroscopic particles of precipitate and in larger particles of Al6(Mn,Fe) or Al12(Mn,Fe)3Si phases, both of which have solution potentials almost the same as that of the solid solution matrix.

4xxx Wrought Alloys and 3xx.x and 4xx.x Casting Alloys. Elemental silicon is present as second-phase constituent particles in wrought alloys of the 4xxx series, in brazing and welding alloys, and in casting alloys of 3xx.x and 4xx.x series.

Corrosion resistance of 3xx.x castings alloys is strongly affected by copper content, which can be as high as 5% in some compositions, and by impurity levels. Modifications of certain basics alloys have more restrictive limits on impurities, which benefit corrosion resistance and mechanical properties.

5xxx Wrought Alloys and 5xx.x Casting Alloys. Wrought Alloys of the 5xxx series (aluminum-magnesium-manganese, aluminum-magnesium-chromium, and aluminum-magnesium-manganese-chromium) and casting alloys of the 5xx.x series (aluminum-magnesium) have high resistance to corrosion, and this accounts in part for their use in a wide variety of building products and chemical-processing and food-handling eguipment, as well as applications involving exposure to seawater.

6xxx Wrought Alloys. Moderately high strength and very good resistance to corrosion make the heat-treatable wrought alloys of the 6xxx series (aluminum-magnesium-silicon) highly suitable in various structural, building, marine machinery, and process-equipment applications.

7xxx Wrought Alloys and 7xx.x casting alloys contain major additions of zinc along with magnesium or magnesium plus copper in combinations that develop various levels of strength. Those containing copper have the highest strengths and have been used as constructional materials, primarily in aircraft applications, for more than 40 years.

The copper-free alloys of the series have many desirable characteristics: moderate-to-high strength, excellent toughness, and good workability, formability, and weldability. Use of these copper-free alloys has increased in recent years and now includes automotive applications, structural members and armor plate for military vehicles, and components of other transportation equipment.

The 7xxx wrought and 7xx.x casting alloys, because of their zinc contents, are anodic to 1xxx wrought aluminums and to other aluminum alloys. They are among the aluminum alloys most susceptible to SCC.

Resistance to general corrosion of the copper-free wrought 7xxx alloys is good, approaching that of the wrought 3xxx, 5xxx and 6xxx alloys. The copper-containing alloys of the 7xxx series, such as 7049, 7050, 7075, and 7178 have lower resistance to general corrosion than those of the same series that do not contain copper. All 7xxx alloys are more resistant to general corrosion than 2xxx alloys, but less resistant than wrought alloys of other groups.

Although the copper in both wrought and cast alloys of the aluminum-zinc-magnesium-copper type reduces resistance to general corrosion, it is beneficial from the standpoint of resistance to SCC.