doctorwayne's Get off yer duff Challenge (Part III)

[doctorwayne]

The next step was to apply rivet detail. This was done using three-dimensional decals from Micro Mark. The usual process is to use a pencil to draw alignment marks on the surface to be decaled, but the shiny metal doesn't accept the pencil markings with even semi-permanence, although the tip of the pencil will actually create a depression in the foil....that's not a good thing. On the car's sides, I used the panel overlaps to determine the vertical rivet placement - the reflective quality of the foil makes viewing difficult, but the decal strips generally ended up where they should have....



On the ends, the only overlap is a horizontal one, but the prototype has three internal channel members to reinforce each end, standing vertically and each attached by double rows of rivets. To situate the vertical rivets, I used dividers to check and compare the spacing of the rows from the car's sides...



I didn't realise until I had all of the end details cemented in place, and was about to begin painting, that I had used the wrong rivet strips for the verticals. Here's another Seaboard car done in the same manner, but with the correct rivet spacing:



I thought about attempting to redo them, but stripping off the incorrect rivets risked damaging the foil, which would have necessitated its removal and that would have required removal of the end details - not something which could have been done without damaging or destroying the details.
I opted instead to go with the wrong rivets, as who else was going to notice....? :hey:

The usual procedure when using the rivet decals is to apply them on a glossy surface (the aluminum tape couldn't be any glossier), then add decal setting solution to make the decals conform to any surface irregularities. I made the first application using Microsol, then followed it up with multiple applications of Solvaset. Unfortunately, not only did the decals not conform to the surface, they also failed to adhere to the surface of the foil with any certainty. (I had previously wiped down all foil surfaces with alcohol to get rid of any fingerprints or surface oils, and allowed it to fully evapourate before decaling, to help ensure decal adhesion.) After several days of applying setting solution with no improvements, frustration got the better of me, and I decided to try something a little stronger. What sprang to mind was MEK, the same solvent used to cement the styrene parts of the car together. I dipped a small brush into the container of MEK, then quickly and lightly, ran it down a rivet strip. Almost immediately, the liquid was drawn under the decal film, and then the film settled over the lapped joints in the foil....success!! I did find, though, that too much MEK or too slow of a pass had the annoying effect of lifting the resin rivets from the decal film, and a couple of seams needed a re-application of rivet decals.

With everything finally securely in place, it was time to paint.
Soon after deciding to use the foil to represent the car's sheathing, I made some paint tests on scraps of foil, with Floquil Grey primer on one, regular Floquil paint on another, and regular Pollyscale paint on a third. The following day, the Floquil primer and paint both scraped off easily, while the Pollyscale seemed to be firmly bonded in place.

Incidentally, if you plan to use this type of foil in a similar manner, I'd suggest cutting it from the back: The foil on the roll has a paper backing which is to be peeled off just prior to installation. I used a sharp #11 blade in my X-Acto (and honed it frequently to keep it sharp so that it wouldn't tear the foil) to cut the foil into strips, but if the foil is cut from the face side, the blade will raise the edges of the tape on both sides of the blade as it passes. Cut from the paper-side, the cut is still clean, but without the raised edges.

Anyway, I mixed a suitable colour using Pollyscale paints, and airbrushed the entire car, as the underbody and truck sideframes on these cars were all painted the same shade of boxcar red as the car's body:





Some areas along the rivet strips seem to have lifted, although it's not overly noticeable in the photos. Since the paint is water-based, I can only guess that the application of MEK, used to set the decals, also reacted with the ca applied to the joints at the overlap of the panels, Before painting, this was imperceptible, but the coat of paint clearly showed where the ca had been too heavily applied, and it also showed where the painted ca had released from the surface of the foil. I use a knife to cut along the worst of the blemishes, then lifted them off, and applied paint, using a brush, to re-cover the bare areas. At least the decals remained attached and intact.

I'm not too pleased with the results, but am going to press ahead and hopefully bring the build to its conclusion. I'll wait a week-or-so to allow the paint to fully harden, then overcoat it with Glosscote to facilitate the application of the decal lettering. That lettering, from Ted Culotta's Speedwitch Media, was the impetus for building this car in the first place, so it's going to be used despite the current state of the car.

In the meantime, I'll begin work on the NC&StL Fowler boxcar, again using experimental (for me, anyway) methods to replicate (hopefully) the prototype. That work will be shown in this thread, too, likely beginning when the Seaboard car is done.

I hope that my mistakes shown here will at least help others to avoid such missteps.

Wayne