Marine Civil Engineering

I planned on putting in an urban waterfront from the start, because this is ostensibly Tacoma, and I find the interaction of rail and water interesting. I have a vision of how I want the various parts of the layout to look, and I’ve been anxious to make that vision more concrete.

The waterfront will require three structures (and water); a seawall, a bridge, and a car pier. The logical method is to build them back-to-front, and by happy accident, I expect that order to be from simplest to hardest. Last week I called in the dredge to excavate the harbor:

Harbor cutaway 1

 

Earlier in the year I’d bought some plastic N-scale stone sheet. I knew the look I wanted, now was time to achieve it. I wanted a stone seawall that looked like it had been in place for years, so I read a number of articles on weathering stone. I found a very useful one on a manufacturer’s site. The link eludes me, but searching for ‘weathering stone model’ or some similar combination will yield all the information one could want. I also watched several videos.

Most sites agreed on several points: use earth colors (Burnt Umber, Raw Sienna and the like) blotch the paint on with a sponge, and use an India Ink wash to bring out highlights. A few articles suggested using a light green wash to suggest moss (or in this case, slime). With weathering sorted, I turned my attention to construction.

While I’ve never done this sort of thing, I know that straight cuts are vital. I searched for a media cutter. What I had in mind was a device similar to a paper cutter, but with a blade held in a trammel that moved over the work surface. If there is such a device, I couldn’t find it. The closest I came was a cutter designed for scrapbooking. Because most sheet styrene I expect to use isn’t much thicker than heavy paper, I may look into it. I came up with a couple of different cutter designs, and it’s probably worth building one. I do expect to acquire a NWSL Chopper in the very near future. Meanwhile, I came up with this Rube Goldberg device to get straight cuts:

Media cutter 1

It’s pure kludge, but it works. By positioning the square along the grid, I can cut material to the desired width. Those clamps, by the way, may be the best tool bargain ever. I got a package of 6 for $1 at the dollar store. They’re strong, have movable jaws, and are of a convenient size. I’m not trying to build a 787 here: I just need something to hold the material in place without slipping.

The seawall sides are longer than the width of the stone sheet, so I used 0.030 styrene as a backing. This was also my first experience with MEK as a bonding agent. Various forums had mentioned how well it works with styrene, so I thought I’d give it a shot. It works very well, although the pieces have to be ready to go, as there is virtually no working time. On a unit basis, it’s about the cheapest glue out there save white glue. My idea was to butt the stone sheet together, apply the MEK, then glue on the styrene backing:

retaining wall construction 1

This worked pretty well. Most of the butt joints were nearly invisible. On to weathering.

My procedure here was to make a thin wash of Raw Sienna oil paint, blotch it on the surface with a sponge brush, then wipe with a paper towel. After drying (a few minutes), I painted on a wash of thinned India Ink and wiped. The last step was to use a very thin wash of Sap Green oil paint. I’m pretty happy with the result:

Retaining wall comparison

That’s a piece of original stock for comparison. The green is very subtle. From some angles you can detect a greenish tinge, and that’s what I was looking for. N-scale slime can only be hinted at.

The idea was to glue the walls in place, then top them with flat styrene strip painted with light grey primer and washed with diluted India Ink to suggest a weathered concrete cap.

retaining wall construction 2

 

 

 

retaining wall construction 3

 

retaining wall construction 6

 

It’s probably much easier to do this before track has been ballasted. I spent considerable time cutting away enough roadbed and ballast to make room for the cap. I couldn’t move the track, so it took several innings to get clearance.

I considered several methods of fixing the gaps, especially the unsightly bastard on the left. Modeling putty would do the job, but dries white, and I didn’t think I could really make it look good. I tried applying MEK with a toothpick, hoping it would weld the styrene together, but that didn’t work. I found some concrete patching compound in the garage, and gave that a go. It was the right color (grey) and hey, we’re repairing stone, right? I applied it with a toothpick, and removed the excess with my finger. It worked fairly well:

Completed seawall 1

 

Completed seawall 2

 

So that’s my foray into building a seawall. Overall I’m happy with this first attempt in modeling a stone structure. I’ll seal the bottom with silicone caulk before moving on to bridge construction.

 

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