THE WINDOWS

A few stages into building my Eaglemoss 1:900 scale U.S.S. Enterprise NCC-1701-D model, I noticed a bad trend regarding the windows.

Problem


Most, if not all, of the windows stick out of the hull. Not only is this inaccurate, but it causes weird shadows at each window when light strikes the hull from the side. Here are a couple of the Eaglemoss promotional photos that help show what I mean:

To confirm my suspicions, I broke out my calipers and started measuring things:

  • The saucer Deck Panels I have received so far are between ~1.3mm and ~1.6mm thick at the window holes
  • Each window part is ~2.5mm tall
  • The windows base ‘flange’ is ~0.6mm

The ‘flange’ is what keeps the windows from falling through the holes, so if we subtract it from the entire window part height (2.5 minus 0.6), that means the actual tab of the window itself is roughly 1.9mm tall. Poking that through a hull that is anywhere from 1.3mm to 1.6mm thick and you can see why they can stick out by over half a millimeter (0.5mm) in some places.

I needed to find a way to reduce the window part heights to match the thickness of the panels so the windows appeared flush or even somewhat recessed. This is what I came up with…

Solution


First, I started hand-sanding the windows down on the sprues with a 1500 grit sandpaper stick:

Then, I used 2400, 3200, and finally 3600 grit sticks to get them smooth and opaque. I did try a 4000 grit as well, but this makes them a bit too shiny for my taste. Ending with 3600 seemed to be a nice dull finish I was looking for:

Since hand-handing is not very accurate, I measured my progress along the way. It seems that just over 2mm total thickness was the sweet spot. This should recess the windows into the hull just a tiny bit:

This same procedure worked for the clear windows as well. The cotton swab was used to wipe them off as I went:

This solution worked pretty well. It is also affordable and can be done by nearly anyone. Here, you can see that my modified windows are not sticking out of the Deck Panel:

Extended Solution


While the previous solution was acceptable, I started to notice that I was not very good at making the window surfaces consistent and flat. They had a tendency to come out be angled or even rounded. Also, I found it time-consuming to sand each window individually.

Along the way, I came up with an idea for a custom tool that would allow me to evenly sand down many windows at once. I also knew it had to be made of metal so it would keep its dimensions during sanding. I quickly put my thoughts to paper and scribbled out this this sketch:

Next, I reached out to a friend who has experience with 3D design and, using free Autodesk Fusion 360 software, he quickly mocked up a STL file of my idea:

I used an online site to convert the STL to DXF format, then sent it over to a local CNC shop. Many, MANY dollars later, I ended up with this:

This little Window Sanding Fixture consists of:

  • 50mm W x 100mm L x 10mm H solid aluminum base block with 3mm holes at the corners
  • 50mm W x 100mm L x 1.4mm H solid aluminum top panel with ten (10) 2mm wide x 80mm long rounded slots
  • 50mm W x 100mm L x 1.2mm H solid aluminum top panel with ten (10) 2mm wide x 80mm long rounded slots
  • Four (4) M3-7 x 3.3 x 0.5mm washers
  • Four (4) M3-0.5 x 14mm Pan Head Phillips screws
  • Four (4) M3-0.5mm Cap Nuts

I super glued the washers to the bottom of the slotted panels (as spacers) to keep it from bending when tightened down:

After that, I started loading windows into the fixture, window ‘tab’ down, like this. Each slot can hold 10 windows, so here I am doing all of the black windows used in Stage 4 at once:

Then, I place the thick base plate on top so can turn it all right side up and the windows stay in place:

Using the screws and nuts, I fastened it all together and got to sanding just like before:

Once the plastic of the windows is sanded down to about the level of the metal, I can set the windows free. If they need more, I can load them up in the 1.2mm thick version of the top panel and do it again:

Finally, I do the clear windows separately so I do not scrape black plastic bits into them while sanding:

When finished, I cleaned up the fixture and the sanded windows, and I am ready to do the next set. It is not perfect, but it is a massive improvement over sanding each window separately while on the sprues. This block is easier to hold and can be placed on the table for more leverage. The windows are coming out at just over 2mm total thickness and all have the same flat ‘tops’ I was going for. Unfortunately, it seems it will only work for the saucer windows, but still, that will save me a ton of time.

Overall, I am happy with my little creation. It was not cheap, so I hope it continues to perform for the rest of the build!

UPDATE Jul 22, 2021: I talked to my CNC shop about a group buy for these and they said they would be around $100 USD and then I never heard from them again. I think a better way would be to just post up my 3D files of the fixture in DXF and STL formats. You should be able to take these designs and have the fixture made locally wherever you are. Enjoy!

DXF (AutoCAD Drawing Interchange Format)
STL (STereo Lithography)

18 thoughts on “THE WINDOWS”

  1. Great Idea, to build such a “tool” for sanding down the windows 🙂

    Since I have ordered some issues on ebay – to try other techniques (such as creating my own windows with clear UV-Resin) – which did not work as perfectly as I wanted – I am using one of the hull plates left to insert the windows and sand them down.

    It is similar to your solution – but of course not as perfect as your’s….
    Maybe, I’ll copy this one… 🙂

    1. Ahhh the windows, all of us have the same problem. I went with some canopy glue and applied it to the rear of each window and let it cure overnight. Once done I used a black sharpie to do the backs of the unlit windows and some black electrical tape to seal light leaks.

      Pros …

      The canopy glue fills the window gaps and doesn’t stick out
      No sanding of supplied windows to get them to the hill level
      It is clearer that the supplied windows and as so looks brighter with the LEDs

      Cons …

      Patience is required in letting it cure
      Bubbles can appear so apply it slowly and use a tooth pick to get rid of them
      I’ve messed up one or two so then you have to let it cure, cut it out and refill

      All in all I am super happy with the results and since I get the list once a month, it gives me ample time to get it done

    1. I didn’t make it myself, I had a local CNC shop make it. I did ask them what it would cost to make like 10 more if I could get a group buy together, but I am waiting on an answer. My guess is close to 100 USD (it cost me $375 to make the first one).

  2. Very interested. Are you willing to share either your STL or DXF files, if a group buy doesn’t pan out?

    1. I’m also very interested in a group run. I live in the UK but happy with whatever the shipping costs would be

  3. I would be interested as well.
    Please sign me up if you make a batch
    Another option would be to share or sell the cad file. That would save a little time while looking for a local shop to print it.

    1. That is exactly what I am doing right now – Converting the 3D files into DXF and STL so people can have them made locally.

  4. Hi All,

    First I have to say a huge thank you to MarvelPhx for this incredible site and such detailed posts for all the hard wok on the mods. Also, a huge thank you for the awesome window sanding jig here.

    I live in upstate NY and found a local shop near me that is able to work with the DXF files for their CNC milling machine. They are hesitant to do any one-off pieces and really only want to invest the time in this as a multi-piece order if it’s do-able.

    I plan to email them the specs today and hope to hear back soon about possibly getting multiple pieces made. I wanted to ask our gracious host here if it was okay to gauge interest in the piece on this site? I don’t want to presume to use your blog as a “market” for this if you’re not in favor of that idea at all.

    Once again, I must express my gratitude at your site here and the great care you’ve taken to share your work with all of us Trekkies and modelers out there. Thanks!

    1. I asked my own machine shop if they would do a ‘group buy’ type purchase, but they hesitated just like yours. In the end, it was just easier to post the files for everyone to use.

  5. Have you needed to use the 1.2mm panel thus far?
    Does it seem advisable at this point to have both plates milled or is the 1.4mm doing the job just fine?

    1. I do use both panels. 1500 or so grit using the 1.4mm for the rough sand down, then finer 1800, 2400, 3600 grit on the 1.2mm panel to smooth them out.

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