How I Actually Saved Money By Printing 3D Parts For My Truck

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The worst part of fixing up an old car is not repairing rusted out body panels, unsticking fasteners that have welded themselves into place, or even troubleshooting a carburetor that refuses to be tuned right. As hair-pullingly frustrating as all of those can be, they are arguably what some people call Type II fun. [Editor’s Note: I thought that was a VW Bus reference but it isn’t. – JT] Despite all the pain and suffering that comes with any of those tasks, in the end, you get to feel good about what you accomplished. 

What never feels good though is getting nickel and dimed as you round up all the fiddly little replacement parts that an old car inevitably ends up requiring. A car you thought you got a great deal on looks a lot less financially wise when you start realizing you’re going to need a $60 turn signal lever, a $20 dome light cover, two $80 tail light lenses, a piece of door trim for $120, and a couple dozen other things. 

My current money pit/labor of love is a 1982 Toyota pickup that I bought from my parents in February. It’s not the most exciting 40-year-old vehicle around, but they bought it brand new, and it holds a lot of memories for me. I learned to drive stick shift in it. I had the worst camping trip of my life in Death Valley in it. When I found out my parents were going sell it, I had to buy it. 

Fortunately, it’s in pretty good shape.  It spent its whole life here in LA, so it has virtually no rust, and my dad is a responsible car owner, so it’s been well cared for. Still, it needs a bunch of those nagging little things. 

While working on it recently, I noticed that one of the little bulbs for the rear side marker lights was dangling by its wires from under the truck. When I unscrewed the two fasteners that were supposed to hold the housing to the body, the entire thing (minus the lens) crumbled into a rotted plastic powder. The marker light on the other side was the same way. A quick glance at the front marker lights suggested they were also going to be trouble. 

 

Crumble

I went looking online for replacements and I found them, but at roughly $40 each, they aren’t cheap. I wasn’t planning on spending $160 on marker lights and I resolved that I wouldn’t. 

[Editor’s Note: Part of why I’m running this – other than I think Emily is great and has a lot of great skills I’m delighted to show you – is that my goal is to make our site the go-to side marker lamp location on the internet. Side markers are the most underappreciated automotive lighting category, and this is part of my personal mission to change that. – JT]

3-D Printing to the rescue

Of my many, many hobbies, most of which have absolutely no practical applications (building sculptures from animal bones etc.), 3-D printing actually has some uses around the house and in the workshop. 

Three-D printing isn’t a new technology anymore and it’s been widely adopted enough that I think I can skip explaining it in depth, and just say it allows the average person to print objects at home. A lot of 3D printing enthusiasts use their printers to churn out busts of Thanos, low-poly Pokémon, and little planters for desk succulents, but I mostly use my printer for solving problems. Think: making brackets, clamps, knobs for electronics, and even a hard-to-find drive belt for a cassette player. 

So, in an effort to save myself from spending $160 on lights for the truck, I got to work with some CAD software and my 3D printer. 

Designing the part

Since the entire housing for the marker light had disintegrated, including the socket the held the light bulb, I wasn’t going to get out of this without making any purchases. To get started, I went to my local auto parts store and found some little light bulb sockets that are somehow meant to fit Ford and GM vehicles manufactured between 1953 and 1999. It didn’t matter which vehicles they were meant for though, because I was going to be printing my own adapters to fit them to my truck, and at $4.99 each, they weren’t a bad bargain. 

Sockets

With those in hand, I began actually designing my parts. On one end, the printed piece would need to fit the socket. On the other end, it needed to act as a gasket between the marker light’s lens and the truck’s body. The socket end was easy. My calipers told me I needed a hole 14mm in diameter. Simple enough. The lens end was harder. The lens isn’t just a rectangle that I could measure and recreate in CAD software. It has sweeping curves and tapers that can’t be easily captured with simple measuring tools. Sure, I could approximate it as a rectangle, but that would look like shit, and if I’m going to work on my truck, I want the results to look nice. 

Measure

Fortunately, I’ve learned a trick for this kind of thing. If you have a relatively flat part with complex curves, you can do a pretty good job capturing its silhouette by laying it on a piece of graph paper and taking a photo of it. Because lenses distort the image they’re capturing to some extent, you want to take the photo from as far away as possible while still having the object clearly visible. The graph paper provides reference lines you can use later to see and fix any distortions that still occurred. 

Lens

After I took the photo, I imported it into photo-editing software, cleaned it up a bit, fixed the little bit of distortion in the image, and then exported it to Adobe Illustrator, which would allow me to trace the outline of the lens and turn it into a file that CAD software understands.

Lenscad1

Then I started designing. The part isn’t complicated. The gasket between the lens in the body has the same outline as the lens itself, except bigger by 1/16th of an inch. It’s got two holes for the mounting screws to pass through, and in the center, it lofts up into a little housing for the bulb and socket. 

Cad2

After designing the part, I set it up to print (a process called ‘slicing’) and printed in thermoplastic polyurethane (TPU), a tough, rubbery plastic. 

Slicer

TPU was ideal for this part because it holds its shape at higher temperatures than some other plastics used in 3D printers, and it’s flexible, which allows it to conform tightly to the body panels of the truck. Each housing only took 90 minute to print, which is pretty darn quick if you consider that some people have prints that take over 24 hours. 

Rev2

The housings printed cleanly and the sockets mated nicely with the 14mm opening I left for them. I printed them in black TPU so the portion exposed on the outside of the truck would match the appearance of the original part. Black isn’t known for being reflective, so I painted the inside of the housings with some silver nail polish, and the parts were done. 

 

Litup

A quick test with my benchtop power supply showed that they lit up very nicely, so all that was left was to wire them up and install them on the truck:

 

Process

 

Conclusions

Often when I find myself trying to avoid spending money on a project, I’m trading money for time. Maybe I saved $50, but at the cost of a few wasted afternoons. This was not one of those situations. Yes, I spent more time on these lights than I would have if I had just bought them online, but it didn’t take that long. This might sound like rationalization, and maybe it kind of is, but maybe it’s not.

I spent about an hour designing the parts, and my printer did basically all the rest of the work. My materials cost was about $20 and change, which is $140 cheaper than buying new marker lights. And I had fun doing it, so I’ll call that a win.

(You can find more of Emily’s DIY projects on her Twitter!)

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91 thoughts on “How I Actually Saved Money By Printing 3D Parts For My Truck

  1. I love this. There is so much hype around 3D printing, but many of the people I know that are into it spend 83% of their time just trying to get things to print correctly. I love seeing something practical come out of it.

    The cost savings shouldn’t be the point here, even if there was some. Being able to make something from scratch to solve your problem is what you can brag about. Add to that, you’re keeping an 82 Toyota on the road!

    1. True, but I’m such a cheapskate that avoiding expenses drives a lot of my tinkerings.

      And yea, 3D printers can be a pain. Once you get them dialed in well, they’re great, but that can take a lot of time and effort. They’re getting a lot better though

  2. Learned so much.
    1. I dislike videos would have loved one here.
    2. I am looking for my soul mate in all the wrong places. Love a smart woman who gets into neat things.

  3. Sorry if I missed it, but what kind of printer are you using? I have used some makerspace 3D printers a couple times so I have a vague familiarity with them in general. I would like to buy one of my own that can do similar projects to what you’re doing. Replacement things for my vehicles, motorcycles, etc. Most of the hobbyist printers I see online seem to be geared more towards people making tchotchkes as you mentioned.

    1. This one is a Prusa MK3S+ I used to have a Monoprice Maker Select that was pretty good, but this printer is a lot better.

      I think most printers can be used for printing useful stuff. They’re tools and they print what you tell them to print. That said, higher end printers can print things more precisely and in a greater variety of materials. A nice printer can print carbon fiber-impregnated nylon, for example, and that’s tough stuff

  4. I’ve made and bought parts for my vintage Toyota. Yeah, the prices of replacements can be high, but when you realize that plastic wiper arm knuckle cap is disintegrating AFTER 30 YEARS OF USE, the replacement cost is put a little more into context.

  5. I’ve been printing stuff for my 06 Jeep LJ for months now, and it’s been great finding STL files online that others have already created.

    AC vents, grille inserts, various fasteners, interior pieces, there’s a lot of stuff out there to be downloaded and printed.

    The latest thing I’m searching for is the tailgate latch cover, but I’ve come up empty.

  6. IIRC, Jason has reported on fixing his cars with things like a rock and duct tape. That is more my style, if I try this I might have to get one of my grandchildren to help me with the 3-D printer.

  7. Welcome Emily! I’m a 3d printing nerd myself. A very strong high-five goes out to you. I look forward to any content you produce for us in the future. I’ve done some of this myself around the house, it can save a TON of money.

  8. This is both awesome and encouraging to read. At least it’s another barrier to older vehicle ownership addressed. Great job being resourceful. I look forward to reading more from you in the future.

  9. This is excellent content for those of us with old, unsupported cars. Is your plan to upload the file somewhere so other toyota truck owners can download and print? It’s possible that people would later take your design and improve on it over several iterations as well.

    Either way, great content!

      1. Great to see you put it on Thingiverse! That should help a lot of people in the future. I hope to someday get to the ‘beautification’ phase for my rolling restorations and contribute in this way as well. Thanks for the reply 🙂

      2. One idea that I hope/wish would catch on for those of us who recreate obscure/NLA car parts, is that people would add the part number of the part they’re recreating to the tags of the thing on thingiverse.

        1. That’s a great point Vgonman.. would be near impossible to find these without the part numbers. When I get started 3d printing parts for my obsolete rides, I will make sure to do so.

  10. This is so exciting. The amount of time I’ve spent attempting to glue/epoxy/JB weld disintegrating impossible to find parts back together, only to wonder how long they really have once they’re reinstalled…

    I hope in the near future, autoparts stores will be equipped to do this for you too, in the manner of a one hour photo setup.

    For me, this is 21st century cool on the order of how the internet and regular printing tech now allows a ton of previously out-of-print books to return via on demanding printing (yeah, I like my books non-screen when I have a choice).

  11. Fixing stuff with 3d printed parts is the best feeling. Especially when the failure you encounter is weirdly specific and would never have been fixable with mass-produced parts. For example, when I bought my most recent car some yahoo had cut off part of the fender liner for the front passenger side. The problem is that this liner is also part of the aero design around the wheels, so when the wind hit it at high speeds it got curled back into the wheelwell and would start rubbing on the tire.

    Sure, I could have replaced the entire fender liner, but all I needed was a replacement for the 4 inches of the front that got cut off so that felt wasteful, both in materials and money. I whipped up a 3d-printed part that approximated the shape of the missing bits, clipped it to the rest of the fender liner with some body clips, and in the year since the only problem I’ve had with it is that I broke the 3d printed part after hitting a small animal (RIP). Being 3d printed though, I just printed off another copy for about 30 cents in plastic and went on my way.

    I once added up all the things I had fixed with my 3d printer and in the end I’m fairly confident it has paid for itself. I’ve managed to fix some fairly expensive stuff for pennies. Of course, you have to know at least some amount of 3d modelling to be able to do that, but if you do it’s great!

  12. Welcome Emily!
    Rest assured that not only you saved money on the expensive replacement parts now, but you also saved money 40 years for now, when the replacements would’ve given up the ghost as well.
    Fine, saving money that far in the future doesn’t mean much, but you probably saved headaches for many other people trying to sort out this kind of issue with that model.

    If the failure rate in your case is that hight, and judging by the price of replacements, I reckon that most owners are facing (or did face) this issue. Is there any sort of database for outdated parts where someone can share the 3d files for them? Imagine searching for a part number and finding all the “implementations” of that design created by users throughout the years…

    1. There are lots of databases for 3D print files. The two I’m most familiar with are Thingiverse and Cults3D. Lots of files are free, some you need to pay for, and Thingiverse has a system where you can tip the designer if you’re so inclined. I’ve just barely dipped a toe into this world so far, but what I’ve found so far is really exciting.

      1. They should host car parts here, or use affiliate links. Another potential revenue stream for the site.

        Everyone appreciates the heavy lifting done here by Optima Batteries, and they will definitely be my next battery because they are the not only the best battery, but the best value for the money, too.

  13. The same turn signal stalk on my old Honda Rebel keeps breaking (three times now, and only one drop!), I feel like if I ever start riding it again, a 3d printer would pay for itself quickly.

  14. Nice article and a great victory, love it! 3D printing is getting quite sophisticated and as with a lot of technology, the price for better and better printers is coming down. I’ve been wanting to get into this myself but frankly hand’t thought of this application, now I need one! Look forward to future articles along these lines. If 3D printing car parts can reduce our expenses as garage mechanics, sign me up.

  15. This is great content. And, as the printers & the materials they use continue to improve, the technology will really help those with niche cars with no parts availability. Plus, this is really winning: not just, I fixed it, but, I MADE it!

    Not car-related, but, I’d like to see an example of the bone sculptures since you mentioned it.

    1. Yes! 3D printing has really helped the obscure car culture create some parts that were not available before. I know that in the RC car arena, 3D printing is a massive boon for people trying to create.

    1. You can already 3D print stuff in nylon and other ‘exotic’ materials that have high enough temperature resistance for certain parts of engines. And there’s a metal 3D printing lab on my employer’s campus. I suppose you could print out metal engine parts. That said, I think that technology is still best suited for small, complex parts that cannot be easily machined. I don’t see anyone 3D printing an engine block any time soon.

  16. I’ve yet to play with TPU. Need to set my printer up for a direct drive, probably.

    Although if I’m going with a funky filament, I’d prefer to play with some of BASF’s metal-impregnated filament and just have a sintered steel part when all is said and done.

    Welcome to the site, Emily? Maybe? Not sure if you’re a full time writer or not, and Torch didn’t help with his ambiguous editorial comments.
    “DO BETTER EDITING, TORCH!” he bellowed, lovingly.

    1. Thanks! It’s good to be here.

      I am a full-time writer, but my day job is writing about science and engineering research for a university. I do a smattering of writing about my hobbies like this.

      TPU is great for so many things. Just this morning I printed some drive belts for a friend’s 8-track player

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