Wheels of Time 35 ft Sealand containers

[nkalanaga]

I received my WoT containers Thursday.  Much nicer rendition than the Shapeways version I already had in service, but...

Shouldn't a "35 foot container" be 35 feet long?  The Shapeways ones are.  The WoT are 36 feet!  So, if I want to run them as containers on a flatcar, I have yet another size to set up the cars for.  At least they made the chassis the same length.  I've seen quite a few pictures of these, in the 60s and 70s, on chassis, on a flatcar, just like any other truck trailer.

The decals also look nice.  The chassis are 3-D printed, and warn that they should be painted with "acrylic or lacquer" paints, "not enamels".  Given the wide variety of solvents used in enamels, that seems a little unspecific.  And what about "acrylic enamels"?

[up1950s]

Maybe WOT 35' is IL and correct at 36 OL , or not ?

[peteski]

The decals also look nice.  The chassis are 3-D printed, and warn that they should be painted with "acrylic or lacquer" paints, "not enamels".  Given the wide variety of solvents used in enamels, that seems a little unspecific.  And what about "acrylic enamels"?

It is a nebulous statement.

Paints nomenclature in the modeling circles is totally out of control.  Adding to the confusion is the fact that not many chemistry details are given on the paint bottle's labels.  Plus modelers seem to cling to the naming convention where "acrylics" is a generic term for all the water-based paints (which usually, but not always are acrylic enamels).

The WoT warning doesn't seem to make much sense because non-water-based "enamels" usually use milder solvents than lacquers. Like Testors PLA enamels which were specifically made for painting plastic (polystyrene) models.

But I also recall that those PLA enamels woudl never dry when using them on raised lettering of vinly model tires. Maybe the resin (or some residue) on those 3D printed parts has a similar effect?

[Ken Martin]

Ask an old trucker.  The container length was dictated by  highway rules in the late 60's in the US SE states when Sea-land set up to go to Puerto Rico.

[nkalanaga]

Ken:  The WoT instructions mention exactly that, and I've never seen an intermodal container labeled by inside length.  The outside length is what matters, so that the various handling carriers know whether it will fit on their train/truck/ship/airplane/etc.

The only correction I'd offer is that the length is from the late 1950s, not 1960s.  40 ft was standard for truck trailers by the late 60s.

[jagged ben]

Reading between the lines I'd say it's pretty clear that they meant oil based paint when they said enamel paint.  Out of date usage, essentially.   Per Wikipedia:

Typically the term "enamel paint" is used to describe oil-based covering products, usually with a significant amount of gloss in them, however recently many latex or water-based paints have adopted the term as well.

[muktown128]

Enamels have some cross-linking or chemical reaction taking place as they dry or cure as opposed to lacquers which dry by solvent evaporation and can be re-dissolved in solvent.  Enamels are typically high gloss, but not always.

Air dry enamels would contain some unsaturated compound like an alkyd resin or oil (molecules that have carbon-carbon double bonds) that will oxidatively cure (cross-link).  Typically, enamels will contain some metal driers (compounds containing cobalt, manganese, zirconium, iron, or some other metal) to accelerate the drying of these coatings. 

The poor cure of air dry enamels over vinyl or rubber is due to either the anti-oxidants or plasticizers used in vinyl or rubber to keep them pliable.  Anti-oxidants in the vinyl or rubber will keep the air dry enamel from surface drying.  Interestingly, anti-oxidants like methyl ethyl ketoxime (MEKO) are used in oil based alkyd paints to keep them from skinning over in the can.

Scott