There is a chill in the air, and the days grow short. It is time to get back to our “Let’s Build a Train” series, this time with 3D printed tank cars. If you have not already done so, please check out one of our other articles to get started. For printing tracks for your train, we recommend Adapted Designs: Let’s Make Tracks!
The 3d printed tank cars we are going to be looking at are another one of the great designs by Depronize. If you have not already done so, we highly recommend you check out his work on thingiverse.com. During our build, we discovered several things that we could do to make our tank cars work better for us. So that is what we are going to share. Tank cars make a fine addition to any train. They are pretty quick to print Let’s get started.
Here is a list of things you will need to make your tank car:
- Depronized’s tank car download. You can download it on Thingiverse.com
- Our download, with some custom parts. You can get it here.
Adapted Design Mods for 3D Printed Tanker
1 file(s) 1.24 MB - PLA filament for your tank car body. We used an assortment for different tankers. But mainly 3D Fila Yellow PLA.
4. PLA filament for each truck. We used Jayo black PLA+
5. Solutech Silver Metal Filament for the wheels. 
6. M3 button head screws (2 screws, 20mm long) for securing each truck to the tank body.
7. M3 “socket head” screws (4 screws, 16mm long) for the trucks themselves. We liked the look of these instead of using the same hardware type throughout. Read below to see why.
8. Some 3mm brass rods. We used these
9. Eight bearings 3x6x2.5mm, type MR63ZZ. We used these
10. M2 sized screws (2 screws, 8mm in length). We chose this one from Amazon because it gives us a good assortment 
11. Some 5mm diameter x 1mm tall magnets. We used these for our custom coupler. There are many vendors that come and go for this item, but we are sure you can find one that will work. We used these.
12. Adhesive to glue the parts of the tank together.
Deciding on a Color Scheme
If you are going to go with a “two tone” color scheme (like we did), you first need to decide what colors to use for your 3D printed tanker. We found that a yellow tank with black “cap” and rail looks very nice, giving the tanker that “Shell oil” look
Printing the “Tank” Portion of The Tanker
For the tank portion you will need to print the following parts from Depronize’s download:
tank_with_hole.stl
tank_without_hole.stl
tank_connector.stl
All of these can be printed on the same build plate, standing up, without supports. We recommend 100% infill as the parts are so thin.
If, like us, you ran into trouble with the tank connector fitting, we suggest instead you use one of the parts included in our download. You will want to print our part:
tank_connector remix.stl
It’s a rescaled part that fits better into each tank half.
Printing the “Ends” of The Tank
Each end of the tank was printed with supports, again, using 100% infill. Both ends can be printed at the same time. You need to print Depronize’s file “buildplate_3_tank_ends.stl” Again, we printed these in 3D Filla Yellow.
Printing Tank Cap, Neck, and Rail
If you are going for that “two tone” look, you will want to print these two of Depronize’s parts in black:
top_cap.stl
handrail.stl
The tank “neck” (top_insert.stl) would be printed in yellow.
Assembling the Tank
To assemble the tank with the least amount of difficulty, we recommend following these steps.
- Glue the top_insert (tank neck) first into one side of the tank.
The reason you want to do this, is because this will eliminate the possibility of blocking the hold with the joiner ring for each tank half.
Next, glue the joiner ring into this half of the tank that you just glued the insert into. You will want to make sure the joiner ring fits BEFORE you apply any glue. Again, if Depronize’s ring fits too snug or will not go in, don’t force it. Try the one we provided instead. Use whichever fits better. Once you are satisfied with the fit, apply glue and install it.
Install the other tank half, gluing it in place.
To line up the tank halves, make sure that the top is lined up. This will ensure that your tank car isn’t “twisted”.
Adding the Tank Ends
We discovered that Depronized did such a great job of designing the tank, that our ends snapped on tightly and required no glue. Yours may do the same.
Adding the Railing and Cap
When adding the railing and cap, we discovered that the holes, in the tank, for the railing, may need to be slightly enlarged. You can use some Harbor Freight or KS needle files for this. But you probably want to dry fit the railing first into the holes before adding glue.
With the tank complete, you can move on to the truck and wheel printing and assembly.
Truck Printing and Assembly
We had a difficult time with Depronize’s original truck design. So instead, we came up with our own. The difference is our design allows the bearings to easily “drop in”. The bearings are retained instead by some clips that become part of the truck assembly instead of being forced in. Here is what you need to print for each truck assembly from our download:
Truck assembly.stl (This include two clips, the truck and the truck mount)
You also want to cut the axles at this time from the brass rods. You will need 4 rods (two per truck). Each rod should be cut 44mm long.
To properly space the wheels, we also came up with some spacers. This takes the guess work out of how far apart the wheels need to be. You will want to print out (4) of the “Wheel Spacer.STL” file included in our download. We recommend printing them out one at a time.
Here is how you assembly each truck:
- Install one of the wheels on the axle. If the fit is “tight”, check out our article on the GP38 truck assembly. (https://www.imagination-3d.com/gp38-truck-assembly-lets-build-a-train/) It clearly shows a method to “press on” the wheels with ease.
2. Slide a wheel spacer onto the axle.
Then slide another wheel onto the axle butting it up against the spacer. You want to try and have equal distance on each end of the exposed axle ends.
3. Place a bearing on each axle end.
4. Place this axle assembly over the truck so that each bearing lines up with the slot in the truck.
5. You should easily be able to push the axle down into the slot so each bearing fits in place in its respective slot.
6. Repeat the process for the other axle. You should now be ready to install the retaining clips.
Installing the Truck Retraining Clips
Each of the clips require one M3 x 16mm socket head screw. First start by inserting the clip into the underside of the truck like this:
The clip should be oriented in such a way as each of the tabs at the end of it “click” into place into the truck.
If your axle bearings are all the way in properly, the clip will then sit flush as shown.
Repeat this for the other side of the truck with the other clip.
Once this is done, start threading in the M3 x 16mm socket head screws.
You can now see why we chose this type of screw. The socket heads fit into the recess of the truck. You do not want to thread the screw in all the way because the next step involves installing the truck mount.
Installing Truck Mount
The truck mount installs in the center of the truck between the screws you just started to thread in. It needs to be oriented so that the hole in the mount is at the bottom closest to the truck.
Here is what the proper orientation of the truck and truck mount. When you have the mount in its proper position, you will be able to thread the screws in the rest of the way.
If you cannot thread them, it’s because the holes in the block are not lined up with the screw. An easy way to get them aligned (if you are having issues) is to back out the screw on one side completely and use a small jewelry screwdriver. Place the screwdriver inside the hole and into the block. This will line up the one side. Then, with the screwdriver still in the hole, thread the other bolt into the hole. Once this is done, you will be able to thread the other bolt in.
Once you are satisfied the truck mount is vertically straight, you will be ready to install the magnetic coupler.
Installing the Magnetic Coupler
The magnetic coupler part you need is contained in our download. You want to print the file “magnetic coupler.stl”. This will give you two couplers. Assembly first involves gluing in one of the magnets in the end of the coupler.
We would recommend that you build “sets” of magnetic couplers (two at a time), with two magnets “stuck together”. If you glue them each into the coupler at that time, it will ensure you have magnets that are not fighting each other.
After the glue dries, you can separate the couplers and install the M2 x 8mm screw into each coupler.
Thread the screw in until its flush with the other side.
Now install the coupler as shown above threading the M2 screw into the truck. You want to place the “Large End” facing “down as shown. You do not need to over tighten the screw. Remember, the coupler is going to swivel back and forth as your train maneuvers around curves. So, you want it to be able to do that. Your now ready to mount the truck to the tanker.
Mounting the Finished Truck to The Tanker
To mount the finished truck to your 3D printed tanker, you will need one M3x20mm button head screw for each truck.
You will need to thread the screw in from under the truck until it is flush with the top of the truck mount as shown below.
Once this is done, you can screw it into the tanker body.
This is how it should look when you have it properly installed.
You don’t want to tighten the mounting screw tight so the truck cannot swivel. Keep this in mind.
Once you have the truck mounted check to make sure that it is in line with the tanker and adjust it if needed. The mounting block will allow you to make minor corrections to the truck. In this way your tanker will sit flat on the track.
That’s it! Your tanker is now fully assembled.
Artwork
Now that you have your tanker assembled, it is time to start thinking about adding some “artwork” to your car. We have included some images in our download which you might be able to use for that. What is below are just suggestions on some things you can do, if you are planning on scaling and printing these out and gluing them (or using similar ones of your own).
Gluing decals
We have found that most glues and adhesive stickers (except for vinyl) don’t work well on PLA. After some period, they start to peel.
The solution? Try this adhesive:
We have found that a light “dusting” of 3M Super 77 multipurpose adhesive works perfect. All you have to do is place the decal or sticker face down in a disposable container. Give it a quick spray dusting, then apply the decal quickly. If you do, your mounted decal will look like this instead with no curling:
We hope you have enjoyed our 3D printed tank car build along. Be watching for more cars soon!
