How To Use a Fluid Writer (Fine Line Painting Pen)


Want to try a unique art tool?

You may have seen people writing with fluid writer pens in art videos on social media. While these pens have practical uses, they’re also fun to use for art like lettering and drawing.

Learn how to use these painting pens so you can try them for yourself with this complete guide!

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If you’d rather watch, here’s a video where I show how to use a fluid writer:

How to Use a Fluid Writer Pen

What is a fluid writer pen?

A fluid writer is a metal painting pen that can be used to apply paint to many different surfaces. It has a reservoir that can be filled with paint. They usually come with a cap and a cleaning tool.

With the right consistency of paint, the pen is very fluid and flows well, which explains the name “fluid writer.” It is also called a fine line painting pen or paint applicator pen.

The most common tip size is a 0.5mm, but there are different sizes available. Some also have a very large well that you can fill with more paint than the tiny wells.

The pens work best when they are held upright, with the tip pointing straight down onto a surface, and they make lines that are a consistent width.

Here’s a link to a good fluid writer pen on Amazon.

Fine line painting pens can be used on paper, wood, fabric, canvas, metal, and probably other surfaces, too. Of course, you’ll have to make sure the paint you use works on each surface for the best results!

How it works

A fluid writer is a pretty simple tool. Once the reservoir is filled with a fluid consistency of paint, the paint will flow down through the tiny tip of the pen and out onto a surface.

You may need to do something to get the paint flowing at first. The paint shouldn’t drip from the pen when you’re not using it, but should only flow when you put the tip on a surface.

A fluid writer can write for a good amount of time before it needs a refill, as long as the paint doesn’t dry up inside the reservoir.

Because these pens are filled with a fluid mixture, the paint/ink can puddle up as you make marks with it. Once dry, the paint usually has a raised-up effect that you can feel if you run your fingers over it.

Here’s one of my Instagram videos that shows a fluid writer in action.

How to use a fluid writer pen

To start using a fluid painting pen, you’ll first need to fill the reservoir, or well. Make sure the paint or ink you’re planning to use is a fluid consistency (like heavy cream) so it will flow through the tip.

Here’s how to fill and write with a fluid writer pen.

  1. Use a dropper or small paintbrush to add paint/ink to the well.

    If using a paintbrush, load the brush with paint and scrape the edges of the pen well so the paint runs off into it.

  2. Fill the well until the paint almost reaches the top.

    You can fill it more if you want, but this way you avoid making an unnecessary mess!

  3. Test the pen on paper to see if the paint is flowing well.

    If it’s not, dip the tip into water or use the cleaning tool to push paint through the tip.

  4. Start writing or drawing!

    Once the paint is flowing through the tip, you can use it to write, draw, or whatever you want. Use a light touch so the pen tip doesn’t scratch up your surface.

If you can’t get the pen to flow well, then the paint is probably too thick. When mixing up paint to put in, it takes a little trial and error to figure out the best consistency.

Use a light touch when using this pen. If you press down hard, the pen tip will scratch and damage the surface and the paint won’t flow well.

For the smoothest lines, try to hold the pen tip upright so the paint/ink flows best. This can be a little awkward for writing, so figure out which pen grip is most comfortable for you.

What to use in fine line painting pens

There are many different things you could fill a fine line painting pen with. The important thing is that the paint or ink is fluid enough to flow well.

The easiest thing to fill the pen with is ready-to-use paint or ink that is already at a good, fluid consistency. Drop it into the little well using a dropper and you’re good to go!

You can also mix up your own paint mixture to fill the pen with. This allows you to use things like metallic watercolors and other fun mediums with the pen.

If mixing up paint to use in a fluid writer, aim for a consistency similar to heavy cream or milk. If you don’t dilute the paint with enough water, it won’t flow well.

Here are some ideas of things you can use in a fluid writer pen:

  • Masking fluid
  • Diluted gouache paint
  • Liquid watercolor paint
  • Diluted acrylic paint
  • Any kind of ink
  • Diluted watercolor paint

Basically, you can fill these pens with just about anything as long as it’s fluid enough to flow well!

I especially like to use metallic watercolors and liquid watercolors. These Ecoline liquid watercolors on Amazon work great.

How to clean a fluid writer

It’s important to clean these pens well after using so that no dried paint or ink is left. Dried paint will clog the inside of the tip and reservoir.

Thankfully, cleaning the pens isn’t too hard if you do it right away! If you’ve left dry paint sitting in the pen, it’ll take more work to clean it.

Some paints, like watercolor, are easy to clean out, while other kinds of paint will be more difficult, especially if they dry quickly.

Here’s how to clean a fluid painting pen:

  1. Rinse the pen in water. If you’re dealing with dried paint, use hot, soapy water and try soaking it to help soften the paint.
  2. Use a brush to scrub away any dried paint. You could a toothbrush or an old paintbrush for this. One with longer bristles would work best.
  3. Push the cleaning tool through the end to clean the inside of the tip. The little tool provided cleans that tiny area where a brush can’t reach.
  4. Rinse again, tap any extra water out, and let it dry. Once the pen is dry, you can put the cap on to protect the tip when storing it.

If you find that the paint/ink is drying as you’re using it, rinse and clean the pen between refills to make sure it doesn’t get clogged.

Here’s another cool trick I recently learned. To unclog the pen tip, you can put the cap of the pen onto the top of the well and squeeze it. The suction pushes the paint mixture out the tip. This might work well for some pen flow issues.

I store my fine line paint pen with other pens, usually with the cap on. While the pen tip is tiny, it isn’t very fragile, so it would be fine to store it without the cap, too. Since these pens are made of metal, they feel very sturdy.

Make sure you keep the lid on the cleaning tool, though, since that tiny tip is delicate!

What is a fluid writer used for?

Fluid writer pens can be used for all kinds of projects. They’re often used for applying touch-up paint to scratches or chips on cars. They could also be handy for touching up marks on furniture.

Of course, the pens are also really fun to use for art, which is this post is about! It’s a unique tool that works on multiple surfaces with multiple mediums, so you can really get creative.

Here are some ways you could use a fluid writer as an art tool:

  • Drawing/doodling
  • Hand lettering
  • Applying masking fluid
  • Writing notes
  • Adding details to artwork
  • Decorating a package

I’ve found that it’s easier to use the pen on a smoother surface, since the tip glides over it more smoothly. A textured watercolor paper, for example, will catch the tip and feel scratchy as you write.

I really like using my fluid writer for lettering, especially watercolor lettering. You can go back over downstrokes to add thickness for that calligraphy look.

Or you could do a mono-line lettering style like the one in this easy lettering style tutorial.

The way the paint dries a little raised-up on a surface is a cool effect that makes it look and feel like embossing, too!

Fluid writer pens are a fun and unique tool to experiment with. I hope this guide gave you all you needed so you can start playing with one yourself. If so, you might want to save it for later!

how to use fluid writer
how to clean fluid writer pen

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