Journal 3dsets.com RC Buggy Build - **Completed project**

[Eric]

So after making putting together the 3d printed coral bandsaw and learning about BLDC motors I found myself asking what other projects use these incredibly powerful and tiny motors? I found a motor part available on printables.com and found the full model was available for a 3d printable vehicle at www.3dsets.com. Not only are these 3d printable model cars very articulated they are also setup to be RC cars! I have never built or raced the serious RC cars, my experience with them was the cheaper kind you would find a drug store. I was itching for another 3d printable build and this seemed like a great way to learn about those more "serious" RC cars and give me a long build that would take a bit of organization and planning to pull off.

I browsed their vehicles and the Buggy V7 spoke to my heart and soul like none of the others. It is clearly inspired on the Baja bugs that are popular in Southern California and has a really fun juxtaposition of the dorky Volkswagen Beetle with Mad max dune buggy. I purchased the files and started reading the manual while trying to decide how to design the livery.




There is a lot of hardware and electronics needed for the build so I started off by ordering the recommended items from the provided BOM wherever I could find them and a kit from www.RCprinter.com. I found RCprinter from a google search but I was happy to support a small hobby business. The seller did a great job of labeling all the fasters and parts. They even have a YouTube channel with videos of the assembly.

 

[Eric]

The print files you purchase come in several formats, there are the individual models in the form of STL files, there are prescliced GCode files for most printers and then there are plates that are not pre-sliced but preassembled in the form of 3MF files. I don't have any specific need to replace the files so I just loaded all the pre-sliced Gcode files on my SD card and started them on the Prusa MK3S+.

There are about 49 "plates" if you print everything which includes two versions of some of the parts as there are two variants of this model. One where the headlights are in the middle on and one where they are on the fender. I am printing and painting them all so I will have some spare parts and the option to configure it either way. It's 49 pre-arranged plates to ultimately make 171 individual peices,


Printing on the Prusa MK3S+, the files are pre sliced at 1.5mm layer heights so the details are preserved but print times are fairly long. The longest is the back half of the vehicle frame (not pictured here) which takes 40 hours!


Some parts are tiny, this one at the pencil's end is a door handle. All parts are sprayed with Rustoleum Automative Primer and wet sanded to 400 grit before painting.

Once they are painted I throw them in my shop dehydrator which I use exclusively for non-food drying needs. I set this to it's lowest setting for heat and it recirculates heated air through the unit allowing the parts to dry to the touch quickly. I don't keep them in here for the entire drying time as many of the paints recommend a drying environment under 90F and the dehydrator's minimum is 95F. I do light coats so there isn't cracking in the paint as the surface dries faster than the wet paint underneath.


With so many plates to print and paint this works best as batch processes. While the next plate prints I am painting/sanding the previous one.

Fresh off the printer with a single coat of primer. The layer lines are still visible until wet sanded.


I experimented with sanding to see how far I could take it within my patience. You can eliminate all the layer lines and give it glossy sheen just by sanding a little past 400 grit. I start at 220 on these prints but have sanding pads that go to 1000. I ultimately decided I do not need to get this level of finish for most parts including the body since I am going to use a glittery spray that has has a bit of texture to it.


These two were my testing to compare wet sanding the primer to 400 and doing nothing. The one on the right has primer and paint but no sanding, the one on the left was sanded first. I definitely like the reduction in layer lines on the left piece so I continue to sand the parts.


Coated in Rustoleum Gloss Protective Enamel - Sail Blue, I then masked the areas that should not get any glitter paint, I do not want the glitter paint interfering with fitting of doors and accessories.

 

[Eric]

For the roll cage bars I did the same primer and sanding but did lay the primer on thick to help smooth them out. After sanding they were painted with Rustoleum Metallic Finish. They have a great metallic look but I think they would really pop if you coated them with a clear coat and polished it. I don't think I'm going to be doing that for the roll bars but perhaps the hub caps.


The light reflectors:


Windows are cut from templates that were printed. They are cut out of Tamiya Clear PLA sheets meant for this exact purpose, model windows. You can see some of the glitter finish on the body in these shots as well.


The dash board was installed with the steering wheel. Most of the parts are fasten with M2 screws and M3 on the some larger body parts. I definitely would not have any of these tiny M2 screws in my shop so I'm glad I bought the kit of hardware. I do have a good collection of M3 screws as they are the standard for 3d printed assemblies, if you like to 3d print getting a mixed set of M3 screws will take you through tons of free projects!

 

[Eric]

This is the smallest I have ever tried to paint before. The B in FEB looks like it's trying to escape but it was a miracle I could get the white dots for the B's counters on there at all and I'm not repainting it! I might make some more vanity plates and try again with new prints though. After all these tags are expired...


Carpets and floors were installed, the center console and back half of the buggy are bolted on as well. Getting the rear window trims and window "glass" installed was definitely the hardest part so far. There are a lot of situations I am running into where the paint has eaten up any tolerances built into the assembly and mated surfaces have to scraped clean or forced.


Doors are functional! I needed to use a little light oil on the mechanisms to overcome some of the tackiness of the glossy paint surfaces but the handles pull out to open the door and pop closed when you close it.



The hood is getting a little extra attention and will have glossy indents and glitter perimeters. I am using blue painters tape for the bulk of it but tamiya model masking tape for the narrow grey parts at the edges since it's a little easier to make around bends.

 

[Eric]

I ended up not liking the masked hood so it all got sprayed evenly. I don't regret this decision but I regret that I didn't a picture of the results of the masking.


Hood and fenders are installed! The headlights have some 5mm clear white LEDS I got as RC headlight+taillight kit. I might replace the headlights with a warmer LED in the future for more authentic look but these are pretty bright!



The engine frame, exhaust and fake rear engine are mounted. The metallic finish rust-oleum really came out nicely on the exhaust. I made sure not touch it much because I have learned it's a very delicate finish that cannot take a top coat without losing it's metallic shine.

I painted some distressed yellow leather seats for the interior. I painted little tears in the seat as I imagine the outside will get naturally weathered to match with time.



Some of the last parts have been printed and painted! There are more accessories to make still like the roof rack and high beams but the buggy itself has been completely printed!

 

[Eric]

Now a wild idea that crossed my mind with making an RC car would be trying to branch out into robotics a bit and basically turn the RC car into a ROV capable of working without line of sight contact. To this end I got a First Person View Camera and headset to mount to the car. The camera and headset are about $70 off amazon and run off 3-5vDC so a small step-down voltage regulator is needed to bring the 2S LiPo battery down from it's 7-9vDC. The camera transmitter gets very hot though so I may also need to wire in a small fan next to it. In this shot you can see the headset capturing live video during my testing on the bench.


Now driving around with FPV sounds pretty fun on it's own but I think it would be even cooler if I could do something remotely with this vehicle. After seeing there are now USB powered pump sprayers for reptile enclosures on the Market I figured that would be a fun addition to the vehicle that would be easy to implement. To make it functional too I could have it spray something useful like Ortho Home Defense to keep these ants invading the house at bay.

RC Trailer:​

I found this 1:10 scale trailer on amazon with the ball hitch attached to it. I wouldn't mind printing my own trailer in the future but the ball hitch looked so nice I didn't think I would be able to do better than that part.



The cute ball hitch with little chains. Adorable.


The buggy drives great with the trailer attached. Reverse is a real challenge as it is with full size trailers, but the hitch seems to rotate smoothly and never came undone during an aggressive test run.

Sprayer Pump:​

The sprayer pump ultimately needs to be separated from it's housing and controller to be operated by the RC pilot alone. I unscrewed the housing on this and unplugged the pump. None of the controller circuitry are needed, the pump will turn on when It gets power and off when it does not.




This is the actual pump sprayer. Amazing they can make something like this with USB power!

"Water" Tank for Trailer:​

Here I am printing a resevoir for the liquid being sprayed. I measured how big of a footprint the trailer would accept and designed a water tank to fit. I used Fusion360 to design the tank, once the external features were done I converted it to a mesh and used shell command to hollow it out. In the future I will not bother converting it to a mesh and will instead design my own cutting tools to hollow it out. I think this would be a better way to design it than using the shell command. The shell command was very quick though so that's what I ended up doing. The print is going to take a long time since I foolishly made the walls very thick. I at least will not have to worry about it getting a nice water tight seal with walls this thick!. I printed in PETG so it can be sealed with Weld-on plastic Solvent on the interior

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[Eric]

It's Alive!​

The maiden voyage! I learned a lot after the first drive. The servo attachment piece needed to be really well secured to handle the strength of the servo turning the wheels with the resistance of the rubber on the concrete. I also need to learn how to drive! This thing can move pretty quickly for it's size and weight!

 

[Eric]

The water tank is complete and I'm test fitting it with the pump on the trailer. A 3d printed cover will go onto the trailer to help make It look more realistic.



The pump is hidden away in some plastic housing designed to kind of look like a industrial pump of some kind. I didn't spend much time on the details of it though so it could use some revisioning down the road.

 

[Eric]

Here's some shots that show how the pump is hidden away. It fits inside this cylinder with a cord escape and uses a small lid with 2x M3 screws to close it up. It doesn't have any gaskets or seals as of yet.

FPV Camera:​

I then set to work on designing a small protective case for the FPV drone camera. The camera and transmitter get extremely hot in use so I am wiring in a fan to help cool it down. I designed the case to funnel the air through at high speed since I think that is the environment this component was designed for being meant for a drone and all.


This is the first version, my second version includes registration points to make assembly and alignment easier as well as an end cap for the exhaust end. This one was perfect for testing though!

 

[Eric]

For the camera my improvised case was a fun experiment to make but I really wanted it to look more like something that should be strapped to the top of the car. I found this hard case that replicates the look of the pelican plastic cases but is already made for 1:10 scale. I brought that model into Fusion360 via the insert mesh option and then converted it to an CAD object and added my allowances for the fan and camera. Despite my previous attempts I ended remaking this object 6 times!

Heavy Duty Case - Jan Jehlička
https://www.printables.com/model/137-heavy-duty-case

Here are some of the iterations of that process, if I had kept a change log I could have done this in half the plastic and time. At least it was fun!



This one was super close to being perfect, unfortunately I stuck the camera too far down and it's obstructed by the luggage rack.



Ah, perfection!


The camera and fan are both 5vDC and the RC car's LiPo battery puts 6.4-9vDC depending on it's charge, but even at low charge that's too much voltage for these components. The fan would survive the overvoltage for a while but I don't think the camera will like it. Fortunately there are a ton of ready made circuit breakouts for this exact purpose. Mine was tiny circuit board completely wrapped in heatshrink with a small sticker that said FPVCAM implying it was meant for this purpose.

These small circuit boards could be stored in the trunk but I decided to have them closer to the components they are regulating the voltage on incase I plan other accessories in the future that want the battery voltage instead. In order to find a space to hide them I hallowed out some of the accessories the buggy came with and hot glued them in. I didn't modify the 3d models I just used an exacto to carve a hole in the bottom of them and pulled out infill with pliers. I then heated up a peice of flat metal like a tongue depressor and used that flatten the infill to remove sharp edges inside.

Backpack voltage regulator:


MMmmmm hot glue! Nothing looks more professional than too much hot glue on electronics. /s
If this part fails I may never get it back out since I went a little too wild with the hot glue. I will print the backpack again and paint it and do it all over again though because it's adorable.


The sprayer pump is also 5vDC so it needs the same voltage regulator. I hid it's regulator in the water jug accessory that came from the buggy kits. Same deal, hot glued inside forever.

 

[Eric]

Servo arm upgrade:​

I don't know if my steering is stiffer than it should be or if a servo arm is just too much to ask of plastic (I suspect it's this one), but I kept chewing up the teeth on the servo arm and losing steering during my stress tests. I tried reprinting it several times in solid ABS plastic but it also lost it's teeth in short order.

The servo came with a metal arm that didn't match the shape or hole locations needed for the 3d buggy so I took a new spare 3d printed arm and modified it with a chisel and exacto knife to fit the metal arm. I had to use a hacksaw to trim the metal arm flush with the length of my plastic arms and then superglued it together in vise.

So far this has completely eliminated any slop in the steering. When this fails I'm sure it will be the coupling of the plastic to metal breaking off, but until that happens I'm happy with the results. Maybe this is a part that should be machined or 3d metal printed in the future when such options are affordable.

Sprayer Attachment:​

The spray nozzles are included with the misting kit, I used it's bulkhead threaded fitting to attach it to one of the buggy accessory bumper lights. I drilled through the light case and fit the nozzle through. The light mount is meant to fit with detents and friction but I drilled through that mount and installed a M3 screw to keep it secured.


A 1/4" PolyPropelene tube runs from inside the front fender, to along bottom edge of the driver side floor, into the rear fender and out the back. I used a blow torch to soften the plastic and then make the sweeps needed to keep it in the shape of the fenders and out of the way of the tires.



10mm silicone tubing can fit over the 1/4" poly tubing with just friction and make a water tight seal that does not come off easily. This section of silicone tubing allows the trailer to turn at the hitch without the tubing influencing it's direction. The silicone tube is very soft and the poly tube is very firm.

Decal work and Livery:​

I found some inkjet compatible water slide decal paper on amazon. I wanted to make red and white stripes for the trailer as I see that on real trailers in my town. Since I wanted white to be included in the design I needed to pick a white background decal paper instead of the usual clear which cannot produce white colors since there is not white ink in home printers.

I found a cloudy font on dafont.com and used photoshop to make the print layout and hazard tape shapes.



It worked great! The waterslide decals are basically just stickers but they incredibly thin. You can see the layer line imperfections will show through the decal because it's so thin. It also means it is not going to come off easily because it has such a good seal against the material you apply it to since its so thin itself. The downside is that you need to apply a sealer after you stick the decal on so that you can protect it since it is so thin. I used crystal clear enamel to both seal the print before soaking in water to apply the decal and after it was applied to keep it protected and sealed to water tank.

First under house exploration!​

I have been so excited to see under the house through the doom buggy's eyes. The FPV headset has RGB video out and use of a capture card allows me to share that experience with you!

 

[Eric]

Resin printed tail light and indicator lenses:​

Printed on an elegoo Saturn Resin printer with “clear” resin. I had not expected the resin to be so yellow but thats okay, it will still work!

Once the print is complete I mount the build plate sideways to let the extra resin drip off into the bat below.


The support structures are auto generated by the slicing software, I am using Chitubox for this printer. Supports this small can be pulled off by hand and work great. Anything bigger than these i usually use the diagonal flush cutters to clip the supports off. I will paint the tail light with a light red wash and use the existing red leds. The creator made a cavity in the lenses for a 5mm or smaller led in each. I currently do not have plans to light the indicator lights but there are available channels on the transmitter to make those functional if I change my mind. I don’t think they will be needed under my house unless I encounter some unexpected traffic down there.