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Reviewing the Molotow Masking Fluid Pen – Plus Tips and Tricks

On the second-to-last day of my last trip to Rome, I was tired, lost, and wandered upon an art supply store on a narrow street near Piazza Navona.

While there I discovered a product I’d not seen in the US before- masking liquid in a pen- and eagerly bought it for about 7€.  I immediately began using it in my travel journal for my paintings of things I saw in Rome and found, after a little testing, that I loved the effects it created.

Reviewing the molotow masking fluid pen art supply

When I got home to Seattle, I was shocked to see the same pen selling in local stores for more than double what I paid in Rome, and, while the price was much lower online, the reviews there at the time were pretty terrible.

After reading a few, I realized that most of the reviewers sounded like they were using the pen very differently than I was- and getting much less satisfying results- so I decided to write this quick tutorial for success using the Molotow Grafx Masking Fluid Pen.

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Paper: Do’s and Don’t

This pen was developed for use on watercolor paper, so you’ll have mixed results when using it on other types of paper. In testing, the BEST results were achieved on very close-fibered, smooth paper- paper that either had NO texture or paper with a stamped texture, like watercolor paper. The worst was on open-fiber paper like sketch pads. Thickness/weight of paper seems to have no effect on the final result.

DO: use on smooth or stamped paper

DON’T: use on open-fiber paper, like sketch pads

Smooth fiber paper like this is essential for success with the Moloto Grafx pen.
Although water color paper has texture, it’s stamped onto the surface rather than being a result of loose pulp fibers. Smooth fiber paper like this is essential for success with the Moloto Grafx pen.
The Molotow masking pen is part of my travel art kit

Masking Pen Prep: Do’s and Don’ts

This is a pump marker, which works very differently from a typical marker. The liquid inside will not flow unless manually pumped into the soft nib. To prep your marker, place the tip on a scratch piece of paper and press down until the nib moves back into the barrel and release. Repeat, gently, until the blue fluid flows well into the nib.

DO: pump the nib into the barrel gentle EVERY time you start to use the pen.

DON’T: use the pen without pumping or when the nib isn’t generously flowing.

prepping a page for watercolor using a molotow masking pen to protect negative white space
prepping a page for watercolor using a molotow masking pen to protect negative white space

TIPS for Using the Molotow Masking Fluid Pen

Because the nib won’t automatically refill, you’ll need to stop periodically and pump the pen. The fluid should be flowing onto the page, rather than the nib feeling as though it is dryly dragging across the page. If the pen isn’t leaving fully opaque, almost-pooling blue marks behind, you need to pump more and reapply.

DO: pump the nib until the pen leaves fully opaque marks.

DON’T: move forward to painting if the mark is translucent or shows the white of the underlying paper- paint WILL bleed.

prepping a page for watercolor using a molotow masking pen to protect negative white space


Painting Over and Removing Molotow Masking Fluid

Let the masking fluid dry fully before painting. I give it about two minutes for details or double that for large areas.

Once dry you can paint over the blue masking fluid. When you have finished watercoloring and the paper is 100% dry, you can remove the masking fluid.

Typically, I rub with my finger to remove the fluid, but you can also use an eraser.

DO: Apply masking fluid thickly, in order to allow easy removal by rubbing.

DON’T: rub aggressively, as aggressive abrasion to your paper may damage to the surrounding color.

Final Thoughts on Using Molotow masking fluid pens

This is my two cents on this somewhat controversial new product: This pen has a learning curve that will disappoint less careful users, but is an outstanding product. I think most of the negative reviews are probably not using the pen correctly. The pen is meant for certain papers, and requires a unique step- pumping. Master those obstacles and lay down a thick layer of masking fluid and give it the appropriate drying time and I think you’ll love this pen as much as I do!

Get yours at Amazon in 2mm Nib or 4mm Nib.

I first learned about watercolor masking fluid in my high school art class. As a budding artist in high school, I reveled in the creative space of my high school’s art department. Often, I even snuck into the art classrooms when I should have been in other classes to check in on a bit of pottery that had just come out of the kiln or to finish up a portion of a painting. I remember the first time I was introduced to masking fluid- it blew my mind!

As a messy watercolor painter, I loved making huge pools of color and blending them together with clear water. Because of the messiness of my style, clean lines were almost impossible to maintain, but masking fluid was a game-changer.

Back then, and especially on a high school art department budget, masking fluid was a precious commodity, and was difficult to use. The tiny bottles of masking fluid- which would have to be applied with a small paintbrush that would inevitably be ruined by the vicious goo- cost over $10 each (and we regarded them so preciously, that often they dried out before they could be used!)

Unless a student artist was working on a final project or a watercolor painting to be entered into a competition, in those days we generally swapped out masking liquid for rubber cement. Like making fluid, rubber cement created a waterproof barrier between the paper and watercolor pigment. However, rubber cement was difficult to apply precisely and even more difficult to remove.

Often, when using rubber cement as masking fluid, the removal after the watercolor paid had dried would result in torn paper and disappointment. What we wouldn’t have given in those days for liquid masking in a pen like these Molotow masking fluid pens which can be applied precisely and removed (usually!) without drama.


Friday 12th of February 2021

I left it on 140 lb arches 2 - 3 hours and it would not come off very easily. my eraser was in bad shape so I shaved off the sticky surface of used fluid - but it took a great deal of pressure and time to get most of it off.


Thursday 20th of June 2019

Having trouble removing from vellum paper. What can I do?


Friday 31st of May 2019

Hi I am having trouble removing the masking fluid. I have rub I use an artist eraser. I am at a loss and at my wits end. Help!!


Wednesday 5th of June 2019

Hi Edith! Unfortunately, some paper just doesn't do well with masking fluid. I'd experiment if it came up a little easier when warm vs cold, and if all else fails you may have to carefully rip it up.

Carla Dixon

Saturday 6th of April 2019

Can replacement nibs be purchased for this masking pen? If so where and what would I buy?


Tuesday 16th of April 2019

I don't think so, but it would definitely be worth sending an email to the manufacturer! They make artist-quality markers, as well, so I would expect that there is a good chance a replacement nib is available.


Monday 4th of March 2019

I am brand new to painting. On my second painting, I used this and followed the directions above, but I'm having trouble getting the marks off. I'm afraid to rub to hard. I tried a kneadable eraser. Should I be more aggressive?

Thanks for your tips! Angie


Tuesday 5th of March 2019

Hi Angie, what kind of paper did you use? You are wise to want to avoid rubbing too hard. I haven't tried this but I wonder if warming or cooling the paper a little would change the lift-ability of the masking fluid?