When in Doubt, Build a Kit

It's been a slow few weeks. Between work, a bit of frustration with the Cricut, and family issues, I haven't done much model building, and didn't have time to do any of the big scenery projects on the layout. I'm mostly blocked on more finish scenery until I build more trees, but that's a messy job that deserves a nice, sunny weekend day.

For a change, I pulled out an old Fine Scale Miniatures kit. FSM is a famous name in the model railroad hobby. They started designing elaborate, highly detailed kits starting in the late 1960's, and were one of the first kit manufacturers to have the idea of limited run kits. They make a fixed number of kits, sell them at one time, and then never sell them again. Modelers buy the kits and hoard them for later, others trade them as collectibles, and some even get built. For building, FSM kits are well known because they included detailed instructions on how to build and weather the kits, because they aimed at board-by-board construction to get a highly-detailed (and usually a bit run-down) look, and because the kits always come with a big handful of tiny castings for every detail item from windows and architectural gingerbread to brooms and cats. Painting all these takes forever, but their kits look beautiful when done. Cynics would accuse FSM of doing caricatures of 1920's buildings - slightly odd buildings with strange additions, immense amounts of weathering and wear, and huge amounts of colorful detail. Sometimes, the built-up kits look a bit more like a Disney or movie-set version of 1930's buildings than is truly real. The caricature charge is probably true; these models are intended to be eye-catching, and they succeeded. As for amounts of wear, I've heard that set dressers on movies can go nuts trying to add all the detail needed to make a scene look correct, and maybe FSM realizes that more than most modelers.

I've never built an FSM kit. I've done a bunch of wooden craftsman kits, some laser cut kits, and done scratchbuilding, but I'd never gotten the full FSM experience. Luckily, Dear Wife was with me at the hobby shop one November, and asked if there was anything around that would make a nice Christmas gift. "How about that kit?" I pointed at a smaller 1970's FSM kit on the shelf; the price was a bit more than an impulse buy, but wasn't that crazy. She got it; it made a good Christmas gift, as it was something nice, and not something I would have bought on my own.


It's been an experience and a time-warp, as it brings back memories of all those 1970's style kit building tricks. They suggest using tiny dots of glue to secure wood to the templates, model airplane-style. They didn't have double-stick tape in the grocery store then. Paints are all solvent-based, and they recommend Floquil brand, back when that was one of the only choices for model railroaders. (Although I followed their suggestions of stains made from black paint, I got similar effects to using Weather-It (vinegar and steel wool wash), as well as using my favorite light grey fabric marker.) The walls were all machine or die-cut, not laser-cut, though they have the cute trick of having the outside clapboards and inside sheathing scribed on both sides of the same sheetwood. I'm also having to figure out how to paint the metal window castings to look like wood, rather than using nice laser-cut windows. They even include a roll of Campbell shingles, originally made from the same material as gummed brown packing tape, and Campbell's aluminum foil-made corrugated roofing. (I might substitute Paper Creek's beautifully rusted printed paper corrugated roofing.) They also suggest detailing the walls by embossing the end of the clapboards and using a pin to simulate nail holes. I'm not sure if all that work makes a difference, but I'll try it once.

It's also been a long time since I've had kit instructions printed on large blueprint-sized paper sheets. With laser-printers and Kinkos available everywhere, most kit manufacturers these days just print on plain paper, and sometimes include color pictures too.

The pictures show my progress - some castings painted, the platform done and looking great, and the building walls looking a bit... dark. I broke away from the instructions to try to make it look as if the building had been painted black originally. (Southern Pacific's engineering diagrams say that non-public facing buildings were painted black with red trim, so I wanted to try doing that instead of the nicer yellow-and-brown seen on stations and buildings along the tracks.)

Still Not Getting the Results I Want From the Cricut

When I bought the Cricut and Sure Cuts a Lot, I was hoping that I'd be able to do work similar to what I'd seen in laser-cut model railroad building kits. My best hope was that I'd be able to cut out a full structure kit out of thin basswood and cardboard. My narrower hopes were to be able to make some of the detailed bits that cut really well in laser-cutting - really fine HO scale windows (with each sash cut out of thin 0.020 cardboard) and strips of cardboard notched to resemble shingles with double-stick tape on the back for adhesion.

The Art Deco building for Campbell showed I could cut a full building, but most of the success there was in cutting the big wall pieces. These aren't particularly hard by hand; it can require a lot of tedious measuring, but cutting out large pieces is pretty easy. I did make the large storefront window from multiple Cricut-cut pieces, and so does count as a success for the cutter. However, I used commercial plastic window castings for the more traditional door and window.

I've tried to make double-hung windows as nice as the laser-cut kits, but the Cricut can't cut them nicely even after I've massaged the SVG line drawings to cut better. I can get paper to cut cleanly with 0.050 inches between cuts, but the 0.020 inch boundaries at sash lines usually tear even with good Strathmore board cardboard. I also still have problems keeping the openings both square and fully cut through. Cutting the entire window opening in a single cut means that the waste piece usually falls out easily, but the corners aren't always square. If I cut the window openings with multiple straight line cuts (cut in both directions), the Cricut still has problems fully cutting through.

Today, I decided to try making shingles. If you haven't seen laser-cut shingles, the shingles are 1/10" wide strips with thin notches cut along one end. To apply these, you glue them to a roof surface, overlapping each row, and with the notches exposed. It makes a neat, realistic roof.

I'd been able to cut small batches of 5" long strips of shingles, but this time I tried to cut a full 6x12 inch sheet of brown construction paper into shingles. I found the cutter does really bad if I'm constantly cutting along the 11" direction because moving the whole carrier sheet back and forth eventually causes the carrier sheet/cutting mat to skew, throw off the cuts, and jam the cutter. I tried reordering the cuts so I did a row of narrow slits across the paper, then moved the paper a bit and cut the next row, and finally cut all the shingles off in one step. I found that even with small movements of the carrier sheet, I still ended up with a 1/16" error from one end of the sheet to the other. Maybe there's some ways to arrange the cuts to avoid the error.

There might be manual workarounds; while cutting all the individual notches for shingles would drive me crazy, cutting the long strips would be a few minutes work with a straightedge. Maybe I could do the slits with the Cricut, and then cut each row of shingles off by hand with a straightedge, or try to cut smaller batches so that there was less chance of accumulating error between cutting the slits and cutting the strips of shingles out. I wouldn't want to do that if I was making shingles to sell, but it'll be easier for the small amounts I need for personal use.

Ugh. I see promise with the Cricut. Watching it cut the slits for the shingles was a nice reminder of the fun of automation - the Circut was cutting several hundred little slits pretty precisely, and doing it all over twenty minutes while I could sit outside and enjoy some nice weather. Unfortunately, I don't feel like I can actually make anything at the level of accuracy for the models. It could do great at curved shapes,so if I wanted to model Gaudi's Casa Badillo in Barcelona (picture borrowed from here, I'd be doing great.

Sigh. Maybe I do just need to bite the bullet and start spending time up at TechShop borrowing time on their laser cutter.

The Scrapbooking Building

Here's the scrapbooking building; it's not completely done, but it's close enough. The glass block window was cut from clear styrene on the Cricut. The first shot shows it temporarily in its correct spot on Campbell Ave. next to a dime store (plastic model, I forget which brand) and a mocked up Campbell Theater (to be kitbashed from a Walther's Bank.)

Some quick checks of the Sanborn Fire Insurance maps show the lot holding the building was empty in 1925, but occupied in the late 1930's. It really is a Streamline Moderne building!

Progress on Campbell's "Glass Block" Building

I've started assembling the curved-front "Glass Block" building for the first time. The first photo shows the scribed 0.030 inch styrene walls. The upper cutout is the inner wall, and the lower one is the outer wall. I did two pieces so I could bend the walls easier, and the main window opening in the inner wall is smaller so that the scribed clear plastic can be glued in flush with the outer wall. The tile crosses at the top of the wall were scribed in lightly; the window and door openings were scribed twice, and the outer wall boundaries were scribed once. I snapped the plastic along the scribe lines.

That sheet actually had to be tossed out; I didn't scale it large enough in Sure Cuts a Lot, so it was about 15% undersize.

This second photo shows the model as it appears tonight. The roof and floor pieces were cut from 0.060 inch styrene by the Cricut; the notches around the edge gave me a place to glue styrene uprights to hold the floor and ceiling apart. The two layers of the building front then were glued to the floor and ceiling. Those nice tile crosses got messed up in this cut somehow, and I'm still not sure what happened. The storefront entrance at the right is multiple layers: the outer wall sheet forms the outer surface, a smaller inner piece (also cut on the Cricut) forms the inner window and door panes, and scale 4x4 styrene framed the doors and windows.

I've also scribed the glass block wall on clear styrene, and I'll glue it in after spray-painting the whole model with a base color. The roof will be finished with black construction paper to simulate tarpaper, hopefully cut on the Cricut to shape.

Model Making Notebooks

Making models with the Cricut cutter isn't working so well. I'm halfway through another model of the glass block building in Campbell I mentioned last time, but I'm not completely sure that the cutter's helping me build any faster. On top of that, I just cut out another facade for the building that ended up at the wrong scale and too small, so I'm not in a good mood. It also turns out the software I'm using is having some issues with curves.

So let's get away from all those topics that might get me cranky, and talk about planning.

Building a large model railroad requires planning and making decisions long before you actually start building a particular scene. One common story describes how John Allen, an early model builder, laid wires for model house lighting in his basement's concrete ten years before he ever needed those wires. Different modelers have different ways of remembering those details: folders full of wiring diagrams, binders packed with historical photos, large track plans and maps pinned on the walls, etc.

In my own case, I keep a set of notebooks where I record progress and scribble occasional ideas, and I had some track plans describing what I wanted to build, but otherwise I keep most of my plan in my head. Occasionally, that causes a problem when I don't remember why I wired things in some specific way, but I've been doing ok with minimal designs.

For my historical modeling, I was most worried about matching historical scenes, and knowing where to look when I needed to see a picture of a particular area or read about the location. I occasionally scribbled maps in my notebook, but I couldn't always find them easy, and they were never precise. A couple years ago, I bought another notebook just for keeping track of such historical details. I sketched out a map of each town or scene, then went through all the books and photos I've got and marked the vantage point where each photo was taken.

These were great when I was trying to understand an area. Where was the telephone shack at Vasona Junction? I'd look at all my photos, make some conclusions about how they were related, and then draw my map and make sure all my assumptions agreed.



They were also useful after I figured an area out. When I started putting in the finished scenery at Wrights (at the top of Los Gatos Canyon), I remembered I'd seen photos of a car parked next to the station, but couldn't figure out how the car got to the station - it would have had to cross the tracks multiple times, and I didn't remember if there was a road from the station area to the road bridge. I flipped open my notebook, checked out all the photos pointing in the right directions, and noticed that there was an interesting fence protecting passengers on the platform from falling down a slope to a road below. It looked like the road dipped under the railroad tracks as they crossed Los Gatos Creek!

I never actually found photos showing the road dipping under the tracks, but the idea made sense, and I looked pretty much everywhere I could and found no better sources. I ended up tearing out a bunch of my nice scenery so I could route the road under the trestle. The great thing is that the road routing looks reasonable, and is a much more interesting scene than I'd been planning, either without a road or with the road just sitting on the same shelf as the railroad tracks. Again, trying to model a specific prototype gave me a much more interesting model than I would have imagined doing!

Using a CNC Cutter for Model Building, Part 2

(If you're directed here from TechShop's blog watch, you'll probably find my live steam locomotive experience more interesting. I was very happy to use TechShop's metal lathe to turn the wheels I couldn't make with my equipment at home.)

I've had a bit more experience with the Cricut CNC cutter and "Sure Cuts a Lot" scrapbooking software for the Mac. So far, I'm making some interesting things with the Cricut, but I think I'd still have better luck with a laser cutter.

To recap: I've seen some beautiful laser-cut model railroad structure kits, and I wanted to experiment with both designing structures flat, and hoped on speeding up my model building a little The Cricut scrapbooking cutter is a small standalone computer-controlled die cutter that can cut sheets of thin cardboard or occasional heavier materials. The Sure Cuts A Lot program is a third-party drawing tool for the Mac or PC that controls the Cricut cutter via USB.

My first experiences (in the last blog entry) showed a bunch of problems. I could draw cutting lines in a drawing program and import them into Sure Cuts A Lot, but found that it would tend to cut shapes with a continuous cut and round corners when doing so. It also wouldn't always cut pieces all the way through, so small pieces (like window openings) would need to be trimmed out by hand. None of this would be a problem if I was doing rounded shapes like letters and clip-art for scrapbooking, but won't work for small model railroad structures where I want sharp corners and need pieces fully cut out to reduce labor.

Luckily, SCAL imports vector drawings in the SVG format - an open, XML-based format, and one that's pretty easy to edit either by hand or with a simple computer program. I ended up writing a quick-and-dirty filter to take my cutting drawings, and massage them a bit so they work better on the Cricut:

* All multi-segment lines get broken into individual straight lines to force SCAL and the Cricut to only cut lines and not try to curve connecting lines.

* All lines get extended about .01 inches to try to cut all the way through at corners.
* Any lines colored red get cut twice, and get cut in opposite directions. I saw the knife didn't always bite through until it had been moving for a bit, so cutting the same line in different directions ensures the whole line length is cut through.

* Any lines colored green are considered scribing or embossing lines, and get placed at the front of the list to draw. After all the green lines are cut, a bunch of tiny lines in one corner of the drawing are added to get the cutting head off the drawing. By doing this, I can set the cutting blade (manually) at its minimum setting when I start, let it scribe all the lines that shouldn't cut through, then change the cutting blade to a deeper setting while the print head's doing the small lines.

If you try this at home, also be aware that SCAL silently fails to cut if any part of your drawing extends outside the cutting area. Make sure to keep your drawing inside the dotted boundary lines. Also make sure to measure your drawing at its largest point in your drawing program, then use SCAL's detail mode to enlarge the vector art to that size so you're cutting at exactly the size you want.

The different behavior for red and green lines is an idea taken straight from the laser cutters which already use different color to use different strengths or speeds of cutting.

By running my cutting drawing through my SVG processing program, I'm getting better results. I've actually used the cutter to scribe individual board lines in cardboard, and find the double-cuts in window openings ensures the pieces get cut through. The picture shows a building front in really thin cardboard. The board lines were scribed by the cutter, and the window openings pretty much fell right out.

The wood-frame office for the Hyde Cannery isn't the best demonstration for the cutter; it's all straight lines and minimal windows, and I know I could cut out all the pieces in an hour with a straightedge and Xacto knife.

A better sample project is this curved-front building next to the railroad tracks in Campbell. This building is visible in photos from the 1930's; the glass-block window in the front and inset tile crosses at the roof line are obvious details that are made for the cutter, either on clear plastic (for the glass block window) or scribed onto the wall itself (for the cross detail.)

I tried cutting pieces of this building out on the Cricut; the result isn't presentable yet, but it showed that the Cricut could actually help me with hobby projects. First, I made my model out of styrene, not cardboard - 0.020 inch for the walls (two thicknesses laminated together for a 0.040 thick wall) and 0.060 inch for a floor and curved form for the wall. I didn't expect the knife to cut through the plastic; I just made sure it scribed the plastic deeply, then I snapped the plastic apart along the cut lines. The curved floor piece (with a 2" diameter curve) required a pair of needlenose pliers to get the plastic to break, but generally the scribe lines from the Cricut were enough to snap the plastic apart. I also learned that the waste material I'd seen between pieces on laser-cut work wasn't needed for styrene; keeping the parts adjacent and snapping them apart saves a lot of work.

The problems with the curved-front building were mostly because of the thin material I used for the walls. The curved base cut nicely, but the 0.020 styrene for the wall didn't stay parallel when only glued to a curve at the bottom of the piece. (It didn't help that the 0.020 plastic I was using was already scribed to resemble individual boards, and the plastic cracked along one of those scribe lines.) For a second try, I'm going to need to cut a floor and ceiling piece (with supports between holding the two apart), then glue the walls to that armature so everything stays square. I'll also need to try to cut some small windows now that I'm getting cleaner cuts out of the Cricut.

So, that's my second week of experience with the Cricut. It's not a laser cutter, but it can do some interesting things. For my little one-off projects, it's not saving me a huge amount of time, but if I was making a lot of identical buildings, it could come in handy.

Using a Cricut cutter for Model Railroading

[Hint: I got better results after this post. Check later blog entries for my experiences with the Cricut.]

Ok, here's my full first-day impressions of using the Cricut. I posted this to the ModelersCad mailing list at Yahoo as well.

I'd seen some questions on this mailing list about using one of the scrapbooking / vinyl cutting die cutter machines for model building. Here's my experiences after one day of experimentation. (See the previous post for pictures of sample cuts.)

Short answer: the machines are interesting, but they're not a substitute for a laser cutter. My cutter (like, I suspect, other die cutters) works best when cutting curved, closed shapes, and tends to put 0.050 radius curves on right angle intersections. Using non-meeting line segments didn't really help; the software with my machine sometimes ignored unconnected lines (that were probably below some size threshold).

If you're doing mostly curved shapes (such as cutting pieces for a model airplane's wing cross members) you could probably do some interesting work in thin wood. If you want to cut lots of right angles, you'll be less happy.

My cheap machine did really well with my modeling materials. 140 pound Bristol board (0.020 inches thick) cut cleanly. It could cut into, but not through heavy (0.050 inch) matboard. Cuts in paper were usually clean, though I did see minor tearing when cut lines intersected. The machine only scribed 0.010 and 0.020 inch styrene, but it was really easy to snap on the scribe lines to get a clean result. I suspect it would work really well scribing 1/16" styrene sheet.

I also tried it on 1/16" basswood with the "thick material" blade. The Cricut didn't cut completely through with a single cut, but it did score the wood pretty deeply so that cutting the pieces fully out would have been easy. The basswood moved around a lot even though it was taped down, so accuracy was a problem.

The other big problem is that while cutting curved letters by hand might be tedious, my models with lots of straight lines are much less work to do by hand. The die cutter helps if I'm doing multiple duplicate pieces, but tweaking cut lines and artwork when doing mock-ups is almost as much work as cutting a new model out of paper by hand.

Long answer:

I'm a model railroader, and I've been interested in doing my own laser-cut buildings in HO (1/87 scale). Unfortunately, I'm too cheap to buy my own, and too lazy to drive 20 miles to TechShop in Menlo Park to use theirs. I was curious if a vinyl cutter like the Klic-n-Kut would give me usable results.

I found a cheap way to start; the craft stores (Michael's, Joann's) often have the Cricut die cutters on sale. I got a 6" x 12" die cutter for $99 on sale yesterday. To use the machine, you place or tape your paper or cardstock on a sticky plastic cutting mat, feed it into the printer, then tell the machine the letters or shapes you want it to cut. The cutting blade is a tiny pointed blade on the end of a 2mm rod; a larger blade holder sets the blade to an appropriate depth that will cut the media but not the cutting pad. The holder stays stationary, but the blade can turn in the holder to handle changes of cutting direction. This turning (and a slight amount of play in the blade holder) means that cutting continuous shapes always results in curves at corners. This is great for lettering (which the machines are intended for), but less good for miniatures having lots of right angles. By contrast, laser cutters are great at square corners.

Cricut cutters only do fixed fonts and shapes, and require you to buy their cartridges ($45) to get new fonts. To use the machines, you type in the letters you want into an attached keypad, and the machine does the cutting.

The Cricuts do have a USB port, but their software won't let you cut arbitrary shapes. Luckily, a third party (www.craftedge.com) sells a program called "Sure Cuts a Lot" (SCAL) that lets you import SVG vector art from a drawing program and cut it on the machine. I had some problems with the SCAL software; it wouldn't connect to the Cricut when I used it with a computer running Mac OS X 10.5, but ran decently on Mac OS X 10.4.(Bzzt. I'd already installed a USB->Serial driver in the past, and it would grab the Crikut device when the OS booted. Deleting /System/Library/Extensions/FTDIUSBSerialDriver.kext got rid of the problem, though now I have to worry why the other driver was installed.) It also imports the art at a different size than my original drawing; I added a 1x1 inch square on my art so I could scale the drawing representing the cuts to the rough size I wanted.

My first project (after a few test letters with the stock Cricut) was a smaller building model. I'm trying to mock up a potential design, so I've been cutting cardboard models out of Bristol board, assembling them, and putting the models on the layout to check size and composition of the scene. Recently, I've tried to make the buildings more real, so I've been drawing the wall shapes and details in a vector drawing program, then printing out these drawings and cutting the pieces free.

Making this model requires some larger cuts for the walls and window openings, and finer cuts for pieces of the windows.

The walls come out ok. Sometimes, the rounded corners are pretty short; on other cases, the blade seems to have trouble finishing the curve and ends up with a spline-like curve that only ends up going straight after a tenth of an inch or so. Interior rounded corners are a little annoying, but can be cleaned up by hand (especially in styrene). Rounded corners on the outside edges are more troublesome; for model buildings, I might be able to cover these with trim.

To really challenge the cutter, I tried cutting the individual window panes out as a laser-cutter would, even though I've not been cutting these by hand. I really hoped the machine could do all the tedious cuts to do individual window frames and panes in a piece whose total size is an inch by 1/2 inch. The laser cutters do beautiful jobs with these sorts of pieces, and it's possible to build up some beautiful windows by layering together multiple pieces. Unfortunately, the rounded edges are a problem.

I also tried cutting the geared calling card available at Thingiverse. (I converted the PDF version of the drawings to line art in the Mac drawing program Intaglio, then exported the line art as an SVG file that could be read in by SCAL. Note all the curved surfaces are set up as line segments, so replacing them with arcs makes the cutting go much faster.) SCAL managed to cut the gears with a lot of up-and-down cutting action, but didn't actually cut through the cardboard fully. It made quick work of the non-gear parts, though. I'll need to try again another time.

So far, I'm not convinced that I can let the computer do all the cutting for my models; the die cutters (at least from what I've seen with the Cricut) just aren't intended for the right angle cuts that all my structure models require. Some of this might be the machine, but I could imagine that some of the problems are with the software that assumes you're cutting out rounded, connected letters. I could imagine tricks the software could do to do better on work like this. It could always do right angles as separate cuts, and do all cuts in the same direction at the same time to keep the blade pointed in the same way. The software could get the blade pointing in the correct direction by starting on a bit of waste material. Nearby cuts could be done at the same time to avoid losing accuracy over several cuts. It's too bad there's no open-source drivers for the Cricut available, or I'd be playing with driving the cutter in different ways to try to get better right angles. Other makers (such as Klic-n-Kut) might do a better job with different kinds of cutting jobs, for all I know.