TWSBI Vac Mini Fountain Pen Overview

Pocket fountain pens have a reputation of low ink capacity and are difficult to fill with bottled ink. Not so with the TWSBI Vac Mini. This compact, vacuum-filling fountain pen holds nearly 2ml of ink. In this post, we take a close look at the Vac Mini, ink it up, and give it a test run to see how it writes.

By the sound of the name, one might think the Vac Mini is a miniaturized version of the TWSBI Vac700R. Rather, the Vac Mini is only about 15% smaller than the Vac700R and shares more design similarities with the TWSBI Mini.

Like the Mini, the Vac Mini has a clear, facet-shaped barrel, a tapered, rounded end cap, and screw cap design.

Like the Vac700R, the Vac Mini's piston rod is clearly visible through the crystal clear barrel. In the "Smoke" version, the front grip section and blind cap are tinted with a translucent black resin.

The clear, faceted cap gently tapers from the wide ring at the opening to the clip and finial at the top. The wedding-ring style band has the TWSBI logo, the words "VAC mini", and Taiwan laser-etched into the polished surface. The round jewel atop the cap displays the red TWSBI insignia. An inner cap sleeve helps prevent the pen from drying out while capped.

Here is the TWSBI Vac Mini compared with the larger TWSBI Vac700R.

TWSBI Vac Mini Specifications

  • Pen Length, Closed: 4.91 in. / 125mm
  • Pen Length, Open (Cap Off): 4.50 in. / 114.5mm
  • Pen Length, Open (Cap Posted): 6 in. / 151.7mm
  • Pen Max Diameter, Barrel: 0.52 in. / 13.3mm
  • Pen Diameter, Grip: 0.39 in. / 10mm
  • Total Weight: 0.85 oz. / 24g

TWSBI Vac700R Specifications

  • Pen Length, Closed: 5.79 in. / 147mm
  • Pen Length, Open (Cap Off): 5.28 in. / 134mm
  • Pen Length, Open (Cap Posted): Cannot be posted.
  • Pen Max Diameter, Barrel: 0.59 in. / 15mm
  • Pen Diameter, Grip: 0.39 in. / 10mm
  • Total Weight: 1.23 oz. / 35g

To accommodate most handwriting styles, the Vac Mini features number 5 stainless steel nibs available in extra-fine, fine, medium, broad, and 1.1mm stub tip sizes. You can swap with a replacement TWSBI Vac Mini nib unit by unscrewing and replacing the section.

Besides the obvious use of writing, the most enjoyable aspect of the Vac Mini is the filling mechanism. The one-stroke plunger mechanism draws nearly 2ml of ink with ease. For a cleaner, quicker fill, TWSBI designed the Vac 20 ink bottle to work specifically with the Vac700R and Vac Mini fountain pens.

Thanks to the high-capacity vacuum filling system, the Vac Mini has nearly double the ink capacity of the Mini. It also has a built-in shut off valve that operates exactly like the Vac700R, Pilot Custom 823, and Opus 88 fountain pens. With the valve closed, the pen is safe from any pressure or heat changes that might cause accidental leaking or burping. Coupled with its pocketable size, the TWSBI Vac Mini is a fine carryon pen for traveling writers.

Like the TWSBI Mini, the screw-on cap of the Vac Mini can be threaded on the back of the barrel with one-and-a-half rotations. The Vac Mini feels comfortable and well-balanced while writing with the cap posted. The generous length of the section gives the writer the secure hold of a regular-sized fountain pen.

The smooth-writing, German-made stainless steel nib performs admirably with ample flow and a slight hint of feedback.

As with other pens that use a shut-off valve, make sure to open the valve by unscrewing the barrel end cap to allow ink flow for longer writing sessions. And, yes, TWSBI designed the cap of the Vac Mini to be posted even with the back end cap unscrewed.

To give the writer more ownership of their writing instrument, TWSBI provides a wrench, replacement o-rings, and silicone grease with instructions on how to properly disassemble and reassemble the Vac Mini when it might require thorough cleaning or maintenance. This is particularly useful for those who need to return their pens to spotless condition.

Do you own a TWSBI Vac Mini fountain pen? Looking to get one in the near future? Let us know in the comments below. Thanks for checking out this pen review