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.

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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.

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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.

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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 🙂

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

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* 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.

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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).

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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.

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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.

I hate airbrushes

Trains

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I was trying to do some airbrushing this evening to use my new spray box but just had a heck of a time trying to get it to spray. What I inadvertently discovered was that if I left parts 1 and 2 off (no idea what they are called) it would spray just fine. Obviously that’s not ideal since that leaves the needle in the open unprotected. If I put part 1 on the air feeds back into the paint reservoir. I have a second identical part 1 that does the same and even tried one for a larger needle but the exact same result.

I’m at a complete loss as to what to try next, if possible I’d like to avoid replacing it again since this is my 3rd airbrush. Do any of my readers have any ideas?

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.

Weekend Update 27

Trains, Weekend Update

It’s been awhile since I’ve posted as I just haven’t had any motivation to work on modeling stuff for a number of external reasons that aren’t really important here.

In my 3D printing I spend a little bit of time looking over websites like Thingiverse and recently I stumbled on a couple of really cool models, first a 1:32 scale EMD SW1500. I’m pretty sure I’m going to print this just because it’s so cool and massive. Second a more generic 16mm scale Diesel Locomotive. I’m very likely going to print that one as well just because it’s cool.

For a couple months now I’ve been searching all over the train room for the wheels to my fairmont speeder with no luck. More than a month ago I resigned myself to the fact that they were gone and I’d just have to order some new ones but thankfully I didn’t because I finally found them. Turns out they were in the garage in a small container on the garage workbench under a pile of miscellaneous stuff that’s piled up since fall. Now I just have to try to remember where I put the rest of the model, though I’m fairly sure that is still in the train room.

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.

Mocking up Buildings

Trains

This has been a slow process, and finally putting that pile of boxes my wife has been bugging me to get rid of to use. Basically I’m trying to recreate a busy industrial scene, but don’t want to end up too busy. I’m not sure if I want to extend background buildings behind the cement plant or if that would look too busy/contrived. Another option would be to use fencing to obscure the horizon on the backdrop… or both.

On the leftmost picture in the bottom left corner there is building that’s open to the operator, my idea is to make this a building that extends off the layout and as such be a cutaway with detailed interior.

The large background buildings will likely be done in brick as older established buildings with some of the smaller foreground buildings mixing up construction types with more of an emphasis on more modern commercial building construction techniques (like steel or concrete etc)

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 😉 ), 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).

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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.

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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.

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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.

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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.

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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).

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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.

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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.