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YOU CAN BUILD A 3D PRINTER THAT PRINTS IN SOLID STEEL

A MIG welding torch on a hacked 3D printer gantry, stacking weld beads layer by layer into solid steel shapes.

by Cranktown City

FULL CAD BOM FIRMWARE DOCS

WorkshopOpen-hardware

Built withArduino

difficulty
●●●●●
time
several weekends
license
license not specified
repo
repo 0 stars

WHAT YOU’LL NEED

Videos
1
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COMPAREE VERDICT

This is a real machine that prints in steel, and also a project with no published files, no BOM and no assembly guide - you build it from what you see in the video. Cranktown City mounted a MIG torch on a reworked Ender 3-based gantry: the welder trigger is a relay switched by the printer board's fan output (M106), an Arduino-driven stepper turns the welder's wire-feed knob, and between layers the torch is dipped in anti-spatter gel. The video is honest about the problems: a bending fixture plate, a wobbly gantry, a weak wire feed, poor grounding and a print that caught fire. The final seven-hour print is, in his words, art - a 'labor-intensive paperweight', not a functional part. Safety is the real project: he built a 16-gauge sheet-steel enclosure with a shade 5 window and admits shade 5 is not ideal for arc welding. If you weld, can tune a printer and can build proper shielding and fume extraction, it is a fascinating experiment in home metal additive manufacturing.

GOOD TO KNOW

  • —No repository, BOM, CAD files or firmware have been published — only the videos.
  • —The build is shown across a YouTube series by Cranktown City (this is part 2), including failed tests - but not step by step, and some parts (like the enclosure) were built off camera.
  • —No licence information is available; cannot determine commercial use restrictions.
  • —The video shows the machine working, but there is no parts list, no drawings, and no published G-code workflow.
  • —You are reverse-engineering from the video and your own knowledge of welding, motion control, and 3D printing.
  • —The enclosure, fume extraction, and electrical safety are mandatory, not optional — a welding arc will burn eyes and skin from across a room.

Parts to buy

12 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • MIG welderFind
  • Stepper motorsFind
  • Linear rails or extrusion for the gantryFind
  • Stepper driver board (e.gFind
  • RAMPSFind
  • SKR)Find
  • Power supplyFind
  • Shielding material for enclosureFind
  • Fume extractorFind
  • Welding gasFind
  • Steel wireFind
  • Relay or SSR to trigger the torchFind

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Can I build this?

Printnothing required
BuyMIG welder, stepper motors, linear rails or extrusion for the gantry, stepper driver board (e.g. RAMPS, SKR), power supply, shielding material for enclosure, fume extractor, welding gas, steel wire, relay or SSR to trigger the torch
Toolsmetalworking tools to build the gantry, electrical tools to wire the controller and trigger circuit, welding safety gear (auto-darkening helmet, gloves, leather apron), multimeter, and a space with adequate ventilation and fire safety
Skillswelding experience, mechanical assembly, 3D printer electronics and firmware (Marlin or similar), electrical wiring, and safety discipline — this is not a first project in any of those categories
Timeseveral weekends to build the gantry, wire the controller, construct the enclosure, and debug the motion and welding parameters — assumes you already know how to weld and tune a 3D printer
Cost$$$; dominated by the MIG welder if you do not already own one, plus the cost of a rigid gantry, stepper system, and proper fume extraction
SafetyThe welding arc emits UV that causes arc eye and skin burns, even from reflections - use proper welding-shade shielding (the creator admits his shade 5 window is not ideal) and never watch the arc unprotected. Fume extraction is required; welding fumes are toxic. In the video an earlier print caught fire, so never leave it unattended and keep an extinguisher at hand. Mains wiring for the welder and controller.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

Videos

DIY Metal 3D Printer (part 2)

The build is shown working, including failed tests, but there is no voice-over parts list or assembly sequence — you are watching and inferring.

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Gallery

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Watch the full video and take notes on the gantry design, the torch mounting, and the enclosure. (There is no published design, so you are reverse-engineering from what you see.)
  2. 2.Choose your motion platform: build a custom gantry or adapt an existing large-format 3D printer frame.(The gantry must be stiff enough to hold position under the weight and vibration of the welding torch.)
  3. 3.Select a MIG welder and confirm it can be triggered by a low-voltage signal or relay.(Most MIG welders can be triggered via their torch switch; you will wire that circuit to a relay controlled by the stepper board.)
  4. 4.Wire the printer board to switch the welder trigger through a relay on its fan output (M106/M107), as in the video, and consider a separate controller for the wire feed.(This is standard 3D printer electronics, but you are controlling a welder instead of a hot end.)
  5. 5.Build or buy a proper welding enclosure with UV-blocking panels and fume extraction before you run a single test bead.(The safety infrastructure is not optional.)

KNOWN ISSUES

  • Underestimating the safety: a welding arc will cause arc eye (photokeratitis) from reflection alone, and fume exposure is cumulative and toxic. The enclosure and extraction are not features, they are prerequisites.
  • Believing you can skip the welding experience. If you cannot lay a clean bead by hand, you will not be able to tune the machine to do it for you.
  • Expecting precision. A weld bead is millimetres wide and layers are visible. Parts come out rough and almost always need machining to be usable.
  • Building a gantry that flexes under the weight or vibration of the torch. The motion system must be stiffer than a plastic printer because the forces are higher and the tolerances are worse.
  • Not planning the welding side of the process: in the video, bead height depended on wire-feed rate (eventually set by a stepper turning the feed knob), spatter jammed the gun until the torch was dipped in anti-spatter gel between layers, and poor grounding stopped it welding at all.
  • Running this indoors without adequate ventilation. Welding fumes are not just unpleasant, they are a respiratory hazard, and the volume produced by continuous printing is significant.

Is there a BOM or a parts list?

No. The video shows the machine working, but there is no published BOM, no CAD files, and no step-by-step build guide. You are reverse-engineering from observation.

Can I use this to replace machining?

No. Parts come out rough, with visible layers and millimetre-scale bead width. Most parts need machining after printing to reach a usable surface. This is additive manufacturing that still requires subtractive finishing.

Do I need a commercial metal 3D printer license or certification to run this?

There is no licensing requirement for the machine itself, but welding generates hazards (UV, fumes, fire risk) that require proper safety measures. In some jurisdictions, commercial welding or operating extraction systems may require permits or inspections.

What can I actually print?

In the video, rough sculptural shapes - the creator calls his seven-hour print 'the most labor-intensive paperweight ever'. Bead width and layer control limit you to chunky forms, and nothing in the video tests the strength of the printed steel.

Community builds

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Discussion1

FROM THE COMPAREE TEAM

The video goes from printing blobs to printing slightly more detailed blobs, but the parts are welded steel. What would you print first if surface finish did not matter and strength did?

CompareeTEAM1mo agoedited

Practical notes from our verification: there is no repository, no BOM, and no published CAD. The video shows the machine working and includes failed tests, which is rare and honest, but you are building from observation. The single biggest decision is whether you already know how to weld — if you do not, this is the wrong project to learn on. The second biggest decision is the safety infrastructure: the enclosure, extraction, and shielding are not optional, and the cost of doing them properly is a significant fraction of the total budget. If you have the welding experience and the space to run this safely, it is a genuine route to metal additive manufacturing outside industrial pricing. If you do not, it is a way to injure yourself expensively. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.

Cranktown City

Cranktown City showed this build on YouTube as a multi-part series - an Ender 3 turned into a MIG-welding metal printer - including the tests that did not work and a print that caught fire.

Star the project on GitHub

DISCLAIMER

  • Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
  • Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
  • Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
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