New year, new office for Leedham’s Mill

It’s been a while – a long while – since I worked on the Leedham’s Mill buildings for Port Rowan. My hiatus from this project was the direct result of being unable to convincingly model the cinder block walls of the office addition.

Leedham Mill - Office addition 3D print

Courses of cinder blocks will be pretty evenly laid, and the finished wall will look straight and neat. I first thought to use a commercial embossed sheet, but I could not find one in 1:64 – and one can’t get away with using a material in a “close-enough” scale, because a cinder block building is defined by its blocks. (Nobody builds a cinder block building that’s “X feet long by X feet high”: they build it “X blocks long by X blocks high”. Window and door openings are defined in terms of blocks, too.)

I decided to try my hand at scratch-building the wall, with block veneers cut from styrene strip. I found it was impossible to keep the pieces in straight rows and my first attempt at the office ended up looking too messy to be convincing:

Leedham Mill - Office first attempt

That was in early 2018, and the project sat idle while I figured out what to do – and then got distracted by other things.

In March of last year, I found a solution: my friend Stephen Gardiner wanted a sound decoder installed in one of the locomotives for his Liberty Village layout, and while we worked on this I asked if he could design some 3D Printed cinder block wall sections for my mill. Stephen has done a lot of 3D Print work for himself and for others. (And while he’s primarily interested in HO scale, one of the most popular items in his Shapeways Store is his S scale track speeder, now available in two styles: Scroll around until you find them.)

Stephen and I measured the model and looked at the prototype photographs, did some math, and figured out the basic dimensions – in blocks – for each of the four wall sections. He then drew up a block, did a lot of copy and paste work, and designed the walls for me.

The prints work beautifully. I mounted the 3D Print material on 0.060″ styrene, sanded the abutting edges to 45 degrees, then cut out openings for four windows and a door.

The next challenge was windows. The project sat some more while I reviewed my options – and then got distracted by other things.

Recently, I noticed that the walls had curled a bit – the 3D Printed material shrinks, apparently. I braced the walls with scrap styrene, then glued them together to form a box – and then decided the only way I could make the windows I wanted was to scratch-build them. I spent a couple of days of cutting and fitting pieces of styrene strip… and in the process I became best friends with Tamiya styrene cement and its little, tiny applicator brush:

Leedham Mill - windows and cement

With the windows built, I applied Tamiya putty to the corners to fill some gaps, then cleaned up the corners with a razor blade and a pick. I also added a styrene foundation – smeared with more putty to give it that concrete look – and then gave everything a shot of primer. I introduced the office to the main part of the building and set it on the layout. So far, I’m pleased!

Leedham Mill - Office Test Fit

Leedham Mill - Office Test Fit

I’ll have to finish painting the office and add window glazing before I can attach it permanently to the rest of the structure, and there are roof peaks to add (plus lots of work on that big wooden building). But the cinder block problem is solved. Thanks, Stephen!

8 thoughts on “New year, new office for Leedham’s Mill

  1. Interesting approach and solution. Quite a few years back I was attempting a similar cinder block building in 1/29. I tried styrene .250 x.250 strips cut into blocks, then glued, scribes lines and then cast wall panels in resin, but it didn’t look right. I got so frustrated with that building I abandoned the project and haven’t picked it up yet.

    Does this mean the rest of the Port Rowan buildings are on the short list of projects?


    • I’m glad I tried the veneer approach. But I’m also glad that Stephen came through with a better approach.

      I’m not sure any projects are “short list” these days. I’ll get to them when I’m inspired. Right now, I’m happy to be working on this office building for Leedham’s – and I will try to keep that momentum going.

      I’m building a number of other projects right now – including three 7mm GWR carriages – but as long as I’m building *something* I call that a win.


      • Trevor,
        I hear you on the 3D prints. Sometimes it is just easier. Projects? What projects? Oh the ones that I started 10 years ago and haven’t finished because another project got priority? I made a goal in September (teacher so that’s the new year to me) to finish a project a month. So far, I haven’t started any new projects, but a few have taken more than amonth to finish. It feels good to finally cross something off the list.

        • There’s a lot I don’t like about 3D Printing – mostly, because I spend enough time in front of a computer and I want my hobby to be something different. But this was an excellent exception.

          As for projects, good to hear about your progress in crossing the old ones off your list. I’m trying to do that too – I’ve looked around my workshop and identified all sorts of half-done projects, and I’ve started doing them. The 7mm British coaches, my Proto:48 equipment, and some HO stuff too. They’re getting done – slowly but surely.


          • To quote Thom Yorke and Radiohead, when it comes to 3D printing, even as an advocate for it….

            In its right place
            In its right place
            In its right place
            In its right place

            In this case, it was the right place and scope for some quick 3D printed cinderblock walls. The problem I see is that with all things that are new, too often its treated as a panacea. In this case, you knew you were getting something that hopefully, if I did a good enough job would look like cinderblocks and remotivate you on this project. I think its safe to say it succeeded!

            Glad to see the mill office progressing again!


  2. The building looks really good, the 3D option really worked convincingly for it! One thing that snagged me in this post that I’d not heard anywhere else: 3D prints may shrink. I’m assuming that is related to the material you’re using but that it happens over time is scary. Is it shrinkage or warpage (which could be due to shrinkage–or not)? What material was it printed in?

    Thanks, Dave

    • Hi Dave:
      I glued the prints to 0.060″ styrene sheet then sanded the edges and cut out the window openings. I left them for several weeks – they curled slightly towards the 3D printed side of the layered wall.

      I assume that’s shrinkage on the part of the 3D print – that the exposed side of the print contracted while the side glued to the styrene did not. I primed the 3D print after mounting it on stryene so it was sealed.

      It wasn’t a lot of curl – but enough that I had to brace the inside of the walls. It also straightened out without any fuss – no cracking or other badness.

      I cannot remember what material Stephen used for these. I’ll ask and then update this comment.


  3. I’ve run into a similar problem. I want to build a model of a CN freight shed erected 1954 at Lindsay, Ontario. CN erected steel buildings from what appear to be kits across its system in the 1950’s using commercial steel panels 16″ wide for sides and roof on a concrete foundation.
    Evergreen Scale Models offers scribed styrene sheet with 3/16″ spacing for modelling these materials. 3/16″ in HO scale is NOT 16″ wide.

    Sort of the same problem you have—

    ” I first thought to use a commercial embossed sheet, but I could not find one in 1:64 – and one can’t get away with using a material in a “close-enough” scale, because a cinder block building is defined by its blocks. (Nobody builds a cinder block building that’s “X feet long by X feet high”: they build it “X blocks long by X blocks high”. Window and door openings are defined in terms of blocks, too.)”

    Which for me is “mutatis mutandis” when modelling a steel structure using steel panels. Fortunately, I just have to scribe some styrene or acrylic sheet. My preference is 1/16″ thick clear acrylic if I can scribe it well enough, and windows can be scribed into that sheet, too. The raised ribs on the roof will call for careful modelling.

    It’s a shame that we don’t have such simple modelling materials in the major scales.

    “Close enough” is often not good enough.

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