Printing Bricks

3D Printing, Trains

I’ve wondered for a while if it’d be possible to print walls, such as brick, for HO scale models. Not because it’d be the most efficient way to get brick sheet but because I didn’t have any brick sheet, and have some brick buildings I want to build, and I have a bunch of filament and a 3D printer why not try.

Live has kept me busy but I finally got around to it and modeled a parametric brick sheet in OnShape. My first attempt was using a 0.4mm nozzle which is the stock size for my printer… it was so bad I disposed of it immediately. I more recently tried a 0.2mm nozzle and had a little better results.

My first attempt exactly off standard dimensions as I found them online. This looks good in cad but just didn’t have enough definition. It was so hard to see straight off the printer I painted it white and then covered in a red. The hope was to catch just the brick faces and leave the white mortar.


That didn’t really work, a wall of it might pass as brick but just didn’t feel detailed enough (and would be nearly impossible to try and lighten the mortar lines as they are just too shallow and narrow.

The next attempt increased the depth and width of these lines (which was really easy thanks to parametric CAD!). This had better results in my quick paint test.


It was definitely an improvement* but I didn’t like how the gap was narrower on the horizontal to ground lines but bigger on the vertical (and this maybe a printer belt issue that’s too small to have noticed previously) and the inconsistency with the brick face bugged me a little so I made the bricks a tiny bit shorter and the horizontal gaps the same amount bigger.


Pulling it off the printer immediately showed the improvement* but painted it really seemed to pop a bit more, especially at a distance. If you get up really close the mortar lines look a little big but I’m thinking that looking good at 3 feet but maybe not 3 inches is better than looking good at 3 inches but not 3 feet.

Certainly there will be more experimentation but looks promising for printing larger wall sections than say Walthers modular system, and with details like doors and windows exactly where I want them… and without having to run to the hobby shop for supplies ūüôā

For my quick tests I also found another use for my printer, specifically the part cooling fan. It makes a great small part paint dryer


* I typed this post up as I was printing and painting these tests but since it was getting a little late I called it a night with the intent of taking pictures the next day and finishing up the post. The next afternoon I didn’t really have time to finish the post but decided fairly quickly that my opinion from the night before was wrong and that the first batch looked better just with a little under extrusion problem on the bricks. I ended up comparing it to a commercially available brick building and the second two attempts ended up looking fairly bad in comparison with giant gaps between the bricks.

So from here I’m going to try and adjust the model back to what I had originally and change my painting method. Rather than painting red on white going to paint them red and then use a white wash to try and get the low spots which might work better with the smaller gaps

3D Printer: Anet A8 Review Update

3D Printing

Two months ago I posted my review of the Anet A8 and I thought it’d be a good idea to give an update after a couple months of use.

Safety First

I’m not going to advocate letting your printer run unattended, this is something you should decide based on experience and should be based on trust that things won’t go horribly wrong. I have let mine run unattended without it starting on fire but I still try to avoid it.

The first safety step is to be careful of bad advice, there is a lot of it out there. Always look at things with a critical eye, especially if it’s accompanied by “should be fine” or something similar. Even be critical of my advice, I will try to only pass on things I have good confidence in but I am fallible and not an expert.

Safe wiring is a must, reading through various forums and Facebook groups I’ve seen plenty of wiring and connectors overheat and badly melt away. A common cause is not doing properly connecting wiring. The Anet comes with some screw terminals that are perfect for spade or ring connectors but doesn’t provide connectors so a common practice is to just stick the wire under the screw and tighten so it holds them in place. This¬†can work but also can also start a fire if not done well and has burnt up many Anet connectors and circuit boards. Get a crimper, learn how to use it, and use the appropriate sized spade or ring connectors.

Never tin stranded wires that will be used in a clamp fitting, whether this is a screw terminal or crimped connection. This actually causes less contact with the the connector and can result in arcing and fire.¬†Similarly don’t solder a crimped connection, you are just compromising the quality of the crimp.

The Anet A8’s board (and many other budget 3D printers) circuit boards are often barely up to spec for the actual current load or in some cases under spec which can manifest in burnt up connectors or circuit boards. You should install a beefy external mosfet for the heated bed at least, and since they are fairly inexpensive do the hot end too. You can read more about how and why to do this on the 3D Print Wiki here.

Finally in the safety category the connector for the heated bed is not rated for the current going through it. It will start discoloring or worse, keep an eye on it or just remove it and solder the wires in directly. Also keep a close eye on the wiring to the heated bed as it’s subjected to a lot of stress through movement.

Things you can improve with printed parts

This is another area where you need to be careful and critical of advice. You don’t need “z-wobble fixes” that fix the Z-axis smooth rods to the Z-axis threaded rod. The reason is that it¬†kinematically over constrain the Z-axis and cause Z-wobble not fix it.

Wiring drag chains are super common but almost never are designed in a way that actually relieves bend stress on the wires and often creating a bigger chance of ¬†wire fatigue than none at all. This not to say you shouldn’t use them, they can be done right (basically the bend loop needs to be fairly large) and do look pretty cool but they aren’t some silver bullet.

Belt tensioning is important on the A8 and having proper tension can have a significant effect on print quality. There are plenty of designs available on sites like Thingiverse and My Mini Factory so I’ll let you chose your favorite or experiment. One word of caution with the Y-axis is to not over tension as the frame is just acrylic and not that strong and will break if you over tighten things. People do tend to over-tighten and then compensate by printing these huge support structures… I’ve had good luck not over tightening things.

As I mentioned in my original review I mentioned the Z-axis endstop fix, totally worth it and makes things way easier to setup. The only other real printer upgrade I’m running is using a glass build surface, I won’t go too into detail as I’m designing some improved parts for it and it’ll be a subject for another post but there are certainly plenty of guides that will show you how online if you can’t wait.

Parts you should keep on hand

I’ve learned the hard way there are some spares you should keep on hand, this is probably not a definitive list just the things I’ve run into so far.

Nozzles: I’ve had¬†one clog, and one complete failure. For a clog I had a little success with removing the nozzle, buying a dollar store baking pan and heating it up to soften the filament and using a needle or tooth pick to help out any bits that won’t drain out. This worked ok, not sure it was worth it though. Replacement nozzles are readily available fairly quickly from places like Amazon and on Amazon Prime but they are super cheap on sites like AliExpress. My advice, stock up on them for like 60 cents each on AliExpress and and if you need one before they arrive Amazon is an option just expect to pay closer to $2 each.

Thermistors: This is the same thing as nozzles, can be found easily on Amazon but way cheaper from far east distributers and if you have a thermistor go out the machine will be out of commission till you replace it. While you are at it some Kapton (polyimide film) will be handy for this repair.

Threaded tube: I’m not sure what the correct name for this is, but this is what I’m talking about. I haven’t broken one of these myself yet but it can be as it attaches the heat block to the extruder and you need to tighten the nozzle while on the machine and heated up so a slip of the tool could snap it. I have some on the way for just in case.

Overall Thoughts

I still think it can be a good deal if you are willing to deal with it’s faults and recognize that this isn’t a machine you set up and use. You set it up and constantly maintain and adjust it to keep it happy. That is not to say a more expensive machine necessarily eliminates all this, but can certainly reduce it.

I’ll leave you with this slightly hypnotic timelapse printing a simple crystal I found on MyMiniFactory. This is a slightly unique model in that it’s printed in what’s called Spiral or Vase mode where it prints the bottom and then does a single constant perimeter till it’s done. It’s a fast way to print models that can support it and very little plastic is used.

Teeny Tiny Pallets

3D Printing, Trains

Earlier this week I posted a teaser on my model railroading facebook page (which you can find here) on a 3D printing project I was working on asking if anyone could guess what it was that I had on this small pallet.


I was being a little bit cheeky in that the pallet¬†these things are stacked on isn’t HO scale, it’s actually O scale (roughly).


Here they are painted and side by side (HO scale on the right and scaled up to 200% on the left which makes it basically O scale) and finished painting so it’s much easier to make them out. You may be thinking, why pallets and it all comes down to Luke Towan’s recent video on making pallets. Just to see if it’d work I made a quick model in CAD and took some stabs at printing it. These are a bit of a challenge to print because they are so small and because there is a lot of bridging. They don’t look as good from the underside and require a bit of cleanup before painting but I think they are pretty nice. This was another project I was able to use my Vallejo Old and New wood paint set to good effect.


This is a very small sample of the ones I haven’t finished up yet, I’ll probably be working on these for a few years.

3D Corner 3

3D Printing

Since Doctor Who is back (on Amazon streaming in the US today, on BBC directly yesterday) it seemed like as good a day as any to finish putting my 3D printed Tardis together.

This item on thingiverse is put together like a kit, and the designer does sell it as a kit on Etsy. He also sells just the lighting kit and the decals which is what I did and printed the rest.

3D Corner 2

3D Printing

This weeks 3D corner is at least in HO scale, I found these container models on Thingiverse (not the painted one, that’s an Athearn) with the 40′ Container here and the 20′ Container here.

I’m thinking I might uses these as scenic pieces on my shelf layout as it’s fairly common to use a shipping container as a storage unit and that gives plenty of range on how I can paint it from new to fairly run down. When painted it should be a little easier to photograph as the white filament just makes it glow.

3D Corner 1

3D Printing

Warning, this post isn’t at all about trains. If you are just here for the trains I totally understand if you skip this one. I won’t name names (so nobody will know I’m talking about¬†you Kris ūüėČ ), but someone was giving me a hard time about my printer review not having any pictures of the cool stuff I’d made. The simple answer to that is I hadn’t finished anything cool yet. One of the biggest surprises to me was just how long it takes to print things, that’s why when you see a video of something being printed it’s almost certainly a timelapse loop. So I’ll be posting updates every once in a while with some of the neat stuff I’ve printed even if it’s not train related. In another note I do have a camera so I can take time lapse video of things being printed but need to get some focus and lighting issues worked out before they are worth uploading.

One of the first projects to finish was a golden snitch (from Harry Potter for anyone wondering what that means).


I got this model off Thingiverse – Golden Snitch with Screw lid, and while this one didn’t turn out perfect do to some printer configuration issues (which I think I’ve got worked out, might try re-printing it) it still is pretty cool. The bottom screws off and there is a little place to hide something (like a stone…). I printed this in part because we are big Harry Potter nerds and because my oldest is turning 11 this month and thought it’d make a cool decoration.

It’s printed in white PLA and primed with Vallejo Gloss Black primer with the idea that the dark base would give it more depth (learned this trick from the Metal Colors I did last summer). Then I painted it with some Gold Vallejo paint and got a nice result.


Next up a neat paint brush stand, which can be found on Thingaverse – ¬†Cubistand, since this one is a mostly functional piece I probably won’t paint it… unless I get bored.


Finally hot of the press printer bed (as I type this) a Deathly Hallows pendant (also Harry Potter… I said we were nerds) which can be found on Thingaverse – Deathly Hallows Rotating Pendant. This one I particularly wanted to try as it’s printed as a single piece but the circle can move freely once you cleanup the supports. I’m not sure how painting this one is going to go while keeping it moveable.

Mixing 3D Printing With Scratch Building

3D Printing, Trains

I’ve been trying to learn CAD for a while now with a couple purposes in mind, first as a way to create drawings of what I’m trying to create to make it easier to convey. As an example of this drawing of a Thrall side beam.


The other would be to use 3D printed parts, or printed tools and jigs to simplify construction. In the example of the thrall side beam I’ve used a scribing tool with some success but it’s still time consuming and easy to make a very visible mistake as this contour is very distinctive. I figured I could go two ways with this, 1) print the piece directly and use it as if I’d cut it or were using a Details Associate or similar piece 2) print a jig to simplify cutting the piece.

Idea one in this case is the simplest so I started with that. Once I got the wheels on my first scratch built flat car it was clear to me just how much weight was needed. Fortunately for that one I had already planned on a load but what if I wanted to run one empty? I need a way to put on some pounds. I’m willing to sacrifice underbody details for the weight, I just need to put it somewhere. I happen to have a collection of steel plates that were salvaged from various lost causes in the past and while they’ll be a little underweight by NMRA standards they should still track a lot better empty.


The solution was to nibble a bit out of the the inside frames as shown on top in the diagram also with the space for the coupler box, bottom shows the profile of an outer frame.

The picture on the left is how the outer beams came off the printer (it’s hard to see ¬†but trust me they are both there), and the right after I’ve removed the brim. The brim is used to give the print a bit more purchase on the print bed so it doesn’t get knocked out of place during printing. Trust me it’s a good idea (nothing like 5 hours into a larger print and having it all lost because one of the pieces came lose).


Here is a comparison of a beam I’ve cut and a printed one. Obviously the printed one has a bit of a stair step look on the angles which could be sanded down, and also obviously I’m not very good with an xacto blade.


The printed version is not without it’s faults either with some cavities that will likely have to be filled in, which for the record is much easier to see in person than to photograph. There are also layer lines, it’ll be interesting to see how noticeable ¬†they are on a finished and painted model. I might also use some filler to smooth it out.

The inner beams I specifically left an area for the weight which is demonstrated on the right. In the left top beam some of the support material is left in place. because of the orientation of the print the center section needed to be supported while printing which just adds a little more cleanup to the part.

So far I’m pretty happy with how these parts came out, it will be interesting to see how they play with the rest of the build.

3D Printer: Anet A8 Review

3D Printing


This was the state of my desk monday when a package from Hong Kong arrived, when I took this picture I hadn’t found any instructions either. It’s an Anet A8 3D printer, the same one Luke Towan has. Unlike Luke I got mine through Amazon but due to a bit of good luck it actually didn’t cost me anything. I won an Occulus Rift through a software developer survey, they fulfilled the prize through Amazon and included a gift receipt so I was able to return it for an Amazon gift card (I actually never opened the Occulus, the day it arrived I gave it back to UPS to head back to Amazon).


The lack of instructions wasn’t really a problem though, I’d found a few good build guides on youtube that were very helpful but if you find your self getting one there are instructions and parts lists on the included MicroSD card.

So why the Anet A8? I picked it for a number of reasons including the price, as a kit it’s fairly affordable (comparatively) for the build volume. It’s also based on a Prusa I3 printer (which is entirely open source) and seems to be one of the best hobby printers you can get. It’s also a kit, so once you get it working you have a pretty good idea how it works and how to fix or upgrade things (true story: most of the things on my backlog to print are parts for the printer).¬†Finally it appears to be a fairly common printer, I was able to find a ton of part models for the A8 on Thingiverse both as replacements (if needed) and as design upgrades liked the Z Endstop Fine Adjustment that I’d highly recommend as it’s super fiddly to get right out of the box (which paradoxically you will still have to do in order to print those parts unless you have a friend that will do it for you).

The build is pretty straight forward, if you are mechanically inclined you probably won’t find it to be difficult.¬†None of the things you need to do are difficult, but the scope of things that needs to be done is a challenge in itself. It comes with all the tools you need… except a 5.5mm wrench, you can do without it’d be a little easier with one for all the M3 nuts. In all it took me about 8 hours from unboxing to fully assembled, that includes keeping an eye on the kids, having supper, and keeping an eye on severe weather (side bar we had >60F on Monday when it arrived and severe thunderstorms, tomorrow it’s supposed to snow… all in a 7 day period). What helped me is doing the research before hand and watching youtube build guides ahead of time so I had a general idea of what I was doing and then referencing those same build guides as I went.

I don’t feel like I’m qualified to comment on 3D print quality as a 3D printing newbie, it’s so far been good for me and it’s important to keep perspective on what 3D printers are good at (which isn’t everything) and focus on using it to it’s strengths.

I don’t really fancy myself as much of a reviewer, and in evaluating this review you should keep in mind that I’ve been 3D printing less than a week but I would say this is a pretty good printer for the money, though it does take an investment of time to assemble and keep it running well.

Raspberry PI and OctoPrint

3D Printing, Electronics

Note: I had originally planned on posting this one after I had assembled my 3D printer but as it appears it’s going to be a while (FedEx has been¬†waiting for it to be dropped off for a week in Hong Kong, don’t think it’s gonna make it to the US by it’s scheduled delivery Monday)

One of the things I wanted to do right away with my 3D printer is to make it a little bit smarter which is where OctoPrint comes in which is a nice piece of software that gives your 3D printer a web interface for management. With Raspberry Pi’s as cheap as they are it makes the OctoPi version a no-brainer.

In addition to a web-cam via the Raspberry Pi Camera Module the Pi’s GPIO pins for a filament run-out sensor and a relay to cut the power to be able to cut power to the printer through the Pi, even remotely.

Filament Sensor

For the filament sensor I found an inexpensive optical endstop sensor (can be found many places, just included Amazon link as an example) and then printed a housing for it. I went with this one as it includes mounts for my printer, but this one is much simpler if you don’t need a mount or want to design your own mount.

OctoPrint has an plugin called Filament Sensor which has instructions for configuring it.¬†The sensor I got came with three pins labeled V, S, and G and absolutely no documentation so I guessed that G was ground, S was signal, and V voltage in. With that highly scientific deduction done I plugged V into one of the 3.3v pins, G into one of the ground points, and S to one of the GPIO pins. I chose GPIO24 as it was near both a 3.3v pin and a ground. Some testing found this appears to work so now I just need the printer so I can print the housing… and use it.

Power Relay

I got a dual relay board (getting the module instead of just two relays for cleaner wiring and mounting. One relay is for turning power on and off to the printer power supply and the other will be used later as a switch for some lighting for the print bed. I used this as a guide for wiring up the relays and configuring them in OctoPrint.

For wiring there were two sets of pins on my relay board. I relied on the internet on this one as I didn’t fully understand it but it seems to work. On the left side was JD-VCC which I wired to 5V, VCC which was wired to 3.3V and GND to ground. The other set of pins had GND (which had a trace to other GND so we don’t need to bother with it), IN1 which I wired to GPIO17, IN2 wired to GPIO18, and finally VCC I wired to another 5V pin.

I’ll defer to this documentation on configuring OctoPrint to have options to flip these relays. Make sure you change¬†/etc/init.d/octoprint and¬†~/.octoprint/config.yaml. Also make sure you use a relay that can handle the power as for this purpose I’ll be running straight mains power through it.

Nice Hat

So I got it all working and even wired up an RGB LED that I have some ideas for future work but it’s kind of a mess and if anything gets unplugged it’s gonna be a hassle to make sure I have the right pins. ¬†What I need is a hat… no seriously that’s what they are called (no I don’t know why). Basically it’s a board that can stack on a Raspberry Pi and provider an expanded interface for the GPIO pins. I picked a cheap one that came with support standoffs (I got¬†this one) and wired it up so it was a little easier to hookup and disconnect as needed. I used some multicolored jumper wires to create cables for each of my purposes and used coloring to make sure I know where things plug in later.

Now all I need is a printer to finish this stuff off!