Motor City Pens V6 and I6: Color-Shifting Fountain Pens With a Party Trick

Introduction

Every so often a small workshop produces something you have not quite seen before. Motor City Pens, a bespoke fountain pen maker based near Detroit, Michigan, makes pens from custom-cast resins, including a thermal shifting material that literally changes color with heat. This review covers two models from that line: the V6 and the I6, including build quality, nib options, sizing, and how they actually feel in daily writing.

The Maker and the Pens

Motor City Pens is run by Alex Fritz, a young maker who got into pen turning as a freshman in high school, started with kit pens like many artisans do, and quickly moved into bespoke fountain pens before casting his own resins. The company name and the exhaust-pipe-shaped logo nod to Detroit’s Motor City heritage, and the pen names follow the engine theme: the V6 references a V6 engine and the I6 an inline six.

The pens arrive in a simple padded box with soft lining and a sleeve. Both models use the same headline feature: a custom thermal shifting resin that changes color based on temperature. The change is not instant. Holding the pen for a few minutes, or even the friction heat from capping and uncapping, can shift the tone, and it slowly returns to its original color afterward. For a dramatic demonstration, a hair dryer transforms the V6 barrel into a very bright green, while the I6 shifts from a dark red into a much lighter, almost pink tone.

The resin itself feels a bit more plasticky and lighter than standard acrylic pens. It does not feel cheap or flimsy, just softer and lighter than what you may already have in your collection.

Design and Build

The V6 is clipless with a blunt rounded cap tip, a straight final inch, a medium step down to the barrel, and a barrel that tapers to a soft rounded point. The I6 has flat ends and a finial on top. Notably, the V6 carries no branding at all, while the I6’s finial bears the company logo. If you prefer your artisan pens to be identifiable at a glance, the I6 wins on that front, and some form of branding on the V6 would be a welcome addition.

Nib and Filling System

Both pens use a stainless steel number six JoWo nib available in extra fine, fine, medium, broad, a 1.1 or 1.5 stub, with a gold nib offered at an additional cost. You can even buy the pen with no nib at a reduced price, a genuinely useful option for collectors with spare nibs. The cap removes in three rotations, the section starts with an elongated flare, and a small step leads to the barrel threads.

The V6 tested here came with a broad stainless steel nib that writes juicy and smooth, with little line variation but plenty of ink flow. The feed keeps up well even with fast writing, and the pen handles reverse writing nicely. These are cartridge converter pens that accept standard international cartridges, and a converter is included. With no metal in the body, eyedropping should also work fine with reasonable precautions. One limitation: the cap is not designed to post, though the pen is long enough to use unposted comfortably.

Measureyments and Size Comparisons

The V6 is comfortably sized for unposted use and has dimensions that echo larger oversized pens while sitting slightly smaller. Compared against common benchmarks, it slots neatly among the Diplomat Arrow, TWSBI Eco, Pilot Vanishing Point, Lamy 2000, and Lamy Al-Star in side-by-side comparisons. Uncapped, it holds its own alongside the Lamy Al-Star, Lamy 2000, and similar oversized resin pens.

Pricing and Availability

The Motor City Pens thermal shift V6 sells for $250, while the I6 model sells for $180. Both are available through the company’s website. As with many small makers, inventory varies depending on how much production time Alex has, and at last check there was no thermal shift stock listed. If you do not see them, the company accepts custom pen inquiries through their site.

Who These Pens Are For

These pens suit fountain pen enthusiasts who want something genuinely different: a hand-cast, thermally shifting resin body that performs as a real daily writer rather than a gimmick. They are also an appealing way to support an emerging artisan maker early in the journey.

The color shift is the obvious draw, but the writing performance holds up too. If you want a subtle conversation piece on your desk, the I6’s red-to-pink shift is the quieter option; if you want maximum drama, the V6’s leap to bright green delivers.

Conclusion

The Motor City Pens V6 and I6 combine an unusual thermal shifting resin with solid fundamentals: a quality JoWo nib selection, a standard cartridge converter filling system, and comfortable unposted balance. The plastic-feeling resin and lack of branding on the V6 are fair criticisms, but at $250 and $180 respectively, both offer something rare in the fountain pen world. Supporting a young maker whose pens also perform nicely is a rewarding way to add personality to a collection.