DIY Guns, Part 3: 3D Gun Making, Advanced Builds, Processes and Techniques

[ED: This is the third part of our series on how to build your own firearms using 3D printing technology. You can read part one here and part two here. Experienced 3D gun maker Ivan the Troll, head of PR for Deterrence Dispensed, has been kind enough to share his considerable knowledge of 3D printing.]

By Ivan the Troll

In this third part of the series, we will cover some of the more advanced builds, processes, and techniques used in 3D gun printing. This is where I believe the most fun lies – builds that push the envelope of possibility, defy preconceived notions of 3D printed guns, and really showcase the ingenuity that 3D printers can enable.

Let’s start with some of the advanced processes used in 3D printing guns.

Fiberglass Heat Welding

Fiberglass heat welding is a technique I sort of stumbled upon when trying to repair damaged prints. I eventually found out that if you lay a fiberglass sheet over a printed part, then use a soldering iron to melt the fiberglass into the part, the fiberglass will become impregnated with plastic and become very rigid when the plastic cools.

This increases the stiffness of the printed part, while also increasing the fatigue life of a printed part significantly. The fiberglass resists the tendency of printed parts to try and crack around layer lines, not only because it adds stiffness, but because the melting process fuses the layer lines together, which tends to prevent cracks from opening up.

This process has many applications, is cheap and easy to use, and can have great results. I compiled an instruction manual of sorts for applying the technique here.

Muh only a few shots https://t.co/7qExfoC7WT pic.twitter.com/7uMr4t1RpG

— Trollworks™️ by Ivan (@Ivan_Is_Back) May 6, 2020

Electrochemical Machining

Electrochemical machining (ECM) is a process that uses electrical current to machine away metal. Not to be confused with electrical discharge machining (EDM), ECM works by electrically dissolving metal. You can think of it as quick, electrically-induced rusting or even electroplating, but in reverse.

ECM has many uses and applications, from engraving to machining very thin parts, but it’s also really useful for machining gun barrels.

ECM has been used to make gun barrels for a long time. The Army tried using it to make barrels for miniguns back in the 60’s, but they found the tooling required to make ECM barrels didn’t justify the cost savings that ECM can have when it comes to actually producing barrels.

A few manufacturers have employed ECM for commercial gun barrel manufacture, namely SIG and Smith & Wesson. SIG rifled pistol barrels with ECM, and Smith rifles their revolvers with it (presumably still to this day).

ECM’s greatest advantage over cut or button rifling is that it introduces no stress on the barrel when cutting (ECM is contactless machining), and ECM can cut metal regardless of the metal’s hardness. ECM is instead challenged by a materials valency/alloy composition — how hard it is to get the atoms in the barrel to abandon their ionic bonds and form compounds with the electrolyte solution used in ECM.

For most alloys we care about — stuff like 4140, 5130, etc. — ECM can cut through it like it’s made of butter. Things like pure titanium and some nickel-based superalloys can be very hard to ECM, but they aren’t great barrel material candidates anyway.

Enough about the theoretic of ECM, though. You’re probably wondering how 3D printing plays into this.

I was inspired by a fellow who goes by the screen name of Jeffrod, who demo’d using 3D-printed tooling to use ECM to rifle a barrel. I was initially taken aback by the complex terms (electrochemical machining sounds a lot more difficult than button rifling). But after I chatted with Jeffrod enough, I got the background info I needed to begin my own experiment with ECM.

I set my sights on a 9x19mm barrel that I would craft out of some 5130 chrome alloy steel tube that I bought from China.

I designed a tooling setup the relied heavily on 3D printed parts, for fixturing, cutting guides, and alignment. Because 3D printers can very easily craft very complex geometry without any additional cost (compared to milling/traditional machining, where you need specialized jigs to create complex shapes), you can easily and cheaply print out the tooling needed for ECM rifling your own barrels.

The most interesting (in my opinion) of these tools is the “rifling mandrel.” A simply printed rod with helical grooves printed into it, it holds copper wires in proper placement so that they can machine the grooves for the rifling pattern the barrel will need.

With the ECM setup, a 4.5” chrome alloy tube can be taken, bored to proper inside diameter (for 9x19mm that is 8.82mm), rifled (the rifling mandrel I designed leaves a multiradial rifling profile…a sibling of polygonal rifling), and chambered (you can either use a plain steel rod or add a taper to it to cut a more proper, tapered chamber) in about two hours.

Once you’re familiar with how the process works, you really only need to check on the setup about five times during these 2 hours. I usually watch Paul Harrel or Forgotten Weapons on Youtube while I let the ECM process cut. I think Paul’s soothing voice makes the barrels come out better.

The end results of ECM rifling are surprisingly good. My first ECM barrel had a mechanical accuracy of 2.5 in at 25 yards using cheap ammo. That’s pretty much on par with GLOCK 17 barrels.

I’ve chronographed these ECM-cut barrels (albeit in a blowback action) against a GLOCK 17 (both the G17 and my ECM barrel were 4.5 in long) with the same ammo and found the ECM barrel was about 100 fps slower, but this is likely more to blame on the blowback action than anything.

The ECM rifled barrels, once done correctly, are very comparable in quality to factory-rifled barrels, a truly amazing aspect of what 3D printing can help bring to the home gunsmith.

And the best part? Aside from the cost of the printer (which, if you remember back in Part 1 of this series, is only about $200), the ECM barreling setup cost me $100. That’ means I can make near-factory quality barrels for around $5 each with $100 in tooling.

There are many other calibers, barrel lengths, and options that can be explored in this sort of DIY ECM barrel rifling. A .44 RemMag, 16”, twist gain rifling barrel is on my list of things to do.

I wrote a comprehensive guide on how to do this yourself in your own home here (download):

https://lbry.tv/$/download/Project-ButWhatAbout-ECM-9×19-Barrel-DIY-V1- Package/792695b9b2986779dccdb6fc9024e40bf6e1bc9a

The FGC-9

The FGC-9 is a firearm anyone can make, anywhere in the world.

Made from 3D-printed parts paired with unregulated metal parts, it stands as a death-blow to future US gun control efforts, and circumvents strict European gun control laws.

And the plans are free to download. pic.twitter.com/qnAAZH7Zjo

The FGC-9 is a hybrid 3D-printed firearm based on the AP-9 by Derwood. The FGC-9 was designed to use an ECM-cut barrel and to lend itself to being a more holistic DIY firearm. It’s designed to use a minimal amount of tooling (about $500) and zero ‘regulated’ parts in its constructed (as Europe defines ‘regulated’ parts, which includes bolts and barrels).

In terms of basic function, the FGC-9 is semi-automatic, chambered in 9x19mm, and feeds from GLOCK magazines (either printed or OEM).

The FGC-9 is the best-proven host of a DIY ECM barrel. I have over 2000 rounds through and ECM barrel mounted in an FGC-9. The barrel has held up well, as we’d expect chrome alloy barrels to do with pistol calibers. Accuracy is still good…there’s no sign of washout or wear on the rifling.

With an ECM barrel, an FGC-9 costs about $100 in supplies to make and reliability is quite good.

The FGC-9 is a firearm anyone can make, anywhere in the world.

Made from 3D-printed parts paired with unregulated metal parts, it stands as a death-blow to future US gun control efforts, and circumvents strict European gun control laws.

And the plans are free to download. pic.twitter.com/qnAAZH7Zjo

— Trollworks™️ by Ivan (@Ivan_Is_Back) April 1, 2020

The FGC-9 files can be downloaded here (it’s a big download because it comes with full assembly tutorial videos and pictorial assembly instruction manuals).

Hopefully now the broader usefulness of 3D printers to the home gunsmith has become apparent. From fiberglass composite parts, 3D printed tooling for electrochemical machining, even drill and welding jigs for the FGC-9, 3D printers are not just for making GLOCK frames or AR-15 lowers. There’s a huge amount of potential these little machines hold.

This 1989 manufacture Browning Hi-Power was victim to a buyback in California.

I’m very pleased to be able to get this back ‘on the streets’ – 30 year old parts resurrected as the next ghost gun in my collection thanks to 3D printing. pic.twitter.com/Bog37RjvVe

— Trollworks™️ by Ivan (@Ivan_Is_Back) May 14, 2020

Read Part 1 in this series here.

Read Part 2 in this series here.

 

Experienced 3D gun maker Ivan the Troll is head of PR for Deterrence Dispensed.