Homemade Masking Fluid for Watercolors

Update: I am no longer recommending using rubber cement (even when thinned) as a masking fluid. One of my visitorsΒ was kind enough to email me about a problem that I was unaware of. Apparently, over time, the rubber cement will cause the watercolor paper to discolor. This definitely defeats the purpose of using it to maintain the white of the paper.

I will leave this post up in case you still want to try it. I know there are some parts of the world where it is difficult to find masking fluid and this may be the only option. I just wanted to post this disclaimer at the beginning so you know what you are getting into.

So far none of the pieces that I personally have used this on have discolored. However, I have only been using this technique for about a year and half, so it still may be too soon. I just don’t want your work getting ruined because of this suggestion! Thanks so much, and sorry for not knowing any better when I posted this.

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Masking fluid is amazing for preserving the white of your paper or protecting details while you paint. Rather than having to carefully paint around tiny highlights or intricate details, you can simply cover them with masking fluid and then apply paint directly over the top of them. When the paint is dry, all you have to do is remove the masking fluid and the paper underneath is completely untouched by the paint.

You can buy masking fluid at just about any art store. However, there are a couple of reasons you might want to try making your own.

  1. Homemade masking fluid is cheaper than commercial masking fluid. Store-bought masking fluid can be a bit on the pricey side. If you are just getting started with watercolors and don’t want to fork out a bunch of money for supplies, making your own masking fluid can save you a little bit of money.
  2. You can find the ingredients at just about any store. If you don’t have an art store nearby, finding masking fluid is practically impossible. If you make your own, however, all you need are a couple of ingredients that you can find at any big-box store.

Technically, if you want to keep things really simple you can just use rubber cement as masking fluid. All you have to do is apply it to the paper wherever you don’t want the paint to go, allow it to dry and then paint over it. When the paint is dry, just gently remove the rubber cement to reveal the paper underneath. It doesn’t get much easier than that.

However, plain rubber cement has one major drawback — it’s really thick and gloppy, which makes it difficult to use for protecting fine details such as hair, tiny highlights in eyes or flower stamen.

Thinning the rubber cement makes it far easier to apply using a fine-tipped brush or even the end of a sharpened stick, a knitting needle, a quill or a bamboo skewer. They sell commercial rubber cement thinner. However, it can be hard to find. Typically art stores or hobby shops carry it. It’s also pretty expensive, which can completely defeat the purpose of making your own masking fluid.

Fortunately, however, there is another option. You can thin rubber cement using acetone. Acetone is cheap and easy to find at any store that carries nail polish. To save even more money, you can use acetone-based nail polish remove instead of pure acetone. It’s often cheaper, and will get the job done just as well as pure acetone.

Disclaimer: Before you try this, be sure you educate yourself about the dangers associated with using acetone and rubber cement.

Rubber cement:Β http://www.elmers.com/msds/me904.htm Acetone:Β http://www.sciencelab.com/msds.php?msdsId=9927062

Rubber cement and acetone both give off dangerous fumes and should only be used in a well-ventilated area. Never use either product while smoking or around open flames. Acetone can also cause damage to polished surfaces and certain types of plastic. Although rubber cement and nail polish remover may seem like common household products, it is important to remember that anytime you use chemicals there are potential hazards. If you try this, you do so at your own risk.

So, without further ado, let’s get started. Here’s what you need:

  • Cheap rubber cement
  • Acetone — or — nail polish remover

Here are some step-by-step photos showing the process:

1
Start by emptying a little bit of the rubber cement out of the jar to make room for the nail polish remover. There should be about an inch to an inch-and-a-half of space at the top of the jar. Once you have room, pour a little nail polish remover into the jar, replace the lid and shake it until it is mixed. Take the lid off and check the consistency. Add more nail polish remover and repeat if necessary. It’s best to add the nail polish remover a little at a time. You can always add more, but if you add too much right off the bat the glue will be ruined.

 

2
After mixing, the rubber cement should have a thin, runny consistency. However, it shouldn’t be watery. It needs to be thin enough to spread easily, but thick enough to protect the paper.
3
To use the masking fluid, simply apply it to any areas that you want to protect using an old brush that you don’t mind ruining. I’m pretty sure the brush I’m using here originally came from a kid’s watercolor set. Just be sure not to use your good brushes for this step. I usually start by painting the liquid around the edges of the area I want to protect, then I go back and fill in the middle later. Be sure to apply a nice, thick coat. You may even want to add a second coat after it dries to ensure that all of the paper is covered.
4
Here’s what it looks like while the rubber cement mixture is still wet. You can see that the coloring of the nail polish remover gave the rubber cement a slight yellowish tint. This makes it easier to see where it has been applied to the paper. Set it aside to dry thoroughly before proceeding.
5
When the rubber cement mixture is totally dry the surface will appear matte. Gently touch it with your finger to make sure it is dry before you paint over it.
6
Paint your background or other details however you want. You don’t need to worry about getting paint in the protected area.
7
Once the paint has completely dried, take a small piece of masking tape and gently rub the sticky side of the tape on the dried rubber cement. It will slowly begin pulling it up off the paper. Continue rubbing the tape on the paper until all of the masking fluid is removed. You can also use an eraser to remove the masking fluid. I prefer to use the tape, however, because it is very gentle and won’t damage the surface of the paper.
8
Voila! Now you can continue with your painting and either add paint to the masked area, or leave it white. (PS. That is one crappy wash that I did there! haha)

I hope this is helpful. Let me know if you have any questions and I’ll be happy to try to answer them. Good luck and have fun! πŸ™‚



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40 Comments

  1. I haven’t tried masking fluid yet because it’s just so expensive when I’m not even sure how much I’ll use it. But this I think I can try. Thank you Beth!

    • Thanks Alicia! That’s exactly how I feel about it, too. I use masking fluid so rarely that it seems silly to spend a bunch of money on it. So far this has been working really well for me as an alternative. Let me know how it turns out for you if you try it.

  2. Thank you so much Beth. I live in a remote part of India–these are hard-to-find items. Looking forward to trying it out. Best wishes!

  3. Thanks for sharing this info, i’m still a newbie in watercolor painting, still trying new things. Art materials here in Phili ppines are a bit expensive, but the materials you had suggested are cheap and easy to find here. Thnk you so much for sharing this.. πŸ™‚

  4. Thank you, especially for the thinning information. I thought I would like to revisit my watercolors and nearly had a heart attack over the $14 price Joanns had on a tiny bottle of masking fluid. Your article will let me try out some ideas without having to feel like I need a second mortgage. Thanks again Mary

    • lol – I know what you mean about needing to take out a loan for art supplies! Sometimes the prices are outrageous. I hope this works out for you!

    • Yeah, small towns and obscure art supplies often don’t mix. I live in a relatively small town, too, so I know exactly where you’re coming from. I hope it works out for you so you can save some driving time! πŸ™‚

  5. thanks for sharing this info. it’s of great help. Actually i’m in a remote corner of my country and even rubber cement is not known to the shop keeper. can i replace it with rubber solution? I am going to try anyway. thanks.

    • Gosh, I don’t know whether or not rubber solution would work as a replacement. Did you ever give it a try? If so, let us know if it worked since I’m sure other people are in a similar situation.

  6. they wanted to charge me $22 at the art supply store for masking fluid! your recipe saved me $18. even the guy at the art supply store was glad to know this tip!
    thank you

  7. Nice solution to replace a very expensive art item – one thing when using masking fluid for those who maybe don’t know – if you wet your brush and rub the bristles on a bit of dry hand soap then dip and use the masking fluid where you want it, the brush is a lot easier to clean when your done with the fluid – just work the bristles under running water to get it clean. Your brush will last a lot longer!

      • Hi Beth, firstly, thanks for sharing this tip. I tried to find an alternative to the expensive masking fluid sold at my art supplies store and I came across your blog. I tried it with nail polish remover and Elmer’s rubber cement. It just wouldn’t mix. They stayed separate like oil and water. Was there something I didn’t do right?

        • Gosh, I’m sorry it didn’t work! I’m not sure why it wouldn’t have mixed. Maybe it was the brand of nail polish remover you used? It seems unlikely since most brands are essentially the same, but that’s the only thing I can think of. You can probably still salvage it if you can drain off the nail polish remover and try just using the rubber cement on it’s own. It won’t spread as nicely since it won’t be as thin, but if you use the right tools to apply it you should be able to get some fairly fine detail with it. Other than that, the only thing I can suggest is maybe trying a different brand of glue or nail polish remover to see if that makes a difference. Sorry I’m not more help! Beth

          • It’s all right Beth, I’m glad to stumble across blogs like yours. It opens up alternatives for me. I didn’t use the whole bottle, just a smidgen of it in a glass jar n experimented with it. So no loss there. Will keep a lookout for other brands of acetone. Thanks again.

          • This happened to mine today also. Ive got Elmers Rubber Cement & Walmart acetone, which has 5 other ingredients in it, which might be messing it up. It’s like oil & water. But your site is great! i’ll look for a different brand of acetone that JUST has acetone in it.

  8. Not sure if it will work well for watercolors, but I’ve used liquid latex as a cheap alternative in place of masking fluid (which is basically thinned liquid latex) for weathering props and armor. Liquid latex is used for “body paint” and special effects/halloween type makeup. You can probably find it at shops that sell halloween costumes this time of year (I believe even big chain stores like Party City carry it), as well as good ol’ Amazon (about $15 for 160z.). You might be able to thin it with Acetone (not sure, never tried it). Might be worth a try, definitely cheaper than commercial masking fluid.

    • I do not know what exactly is ‘rubber cement’. In my area products are called differently in our language. But I do have something that you use to patch, say, leaky rain gutter. Looks like white toothpaste. Its called ‘aquaproof’. It has rubbery feels. But it stucks to papers like hell. Is it the same thing?

      • I looked up the stuff that you were asking about and it is definitely not the same thing. Rubber cement is transparent and it easily comes off of paper. Here in the U.S. you can usually find it at stores that sell office supplies. If you can’t find it locally, you may be able to order it online. Of course, once you factor in the cost of shipping, you may find that it’s not much cheaper than actual masking fluid. Hopefully you will be able to find something affordable that will work! If nothing else, you can cut pieces of masking tape to fit the areas that you want to protect. It is time consuming, but it does work. Good luck!

  9. I have used rubber cement and thinner for 50 years ,completing over 13,000 paintings using it as a frisket . Never had a problem with it unless you don’t get it all off- Rub your fingers over the area that was covered after using the Pick-Up, to make sure all is off-

    • Interesting idea. I tried to do some research on the differences between the liquid latex that is used for makeup effects and the liquid latex that is used for masking fluid. In essence, it looks like the stuff that is designed to be used on the skin contains less ammonia that the stuff that is designed for crafts. Here’s a blurb about it from Wikipedia:

      “Cosmetic liquid latex contains approximately 0.3% ammonia to increase shelf-life. Craft and mold making latex can contain more than double this amount and as a result, has a much stronger odor. The fumes from the ammonia in liquid latex can irritate the eyes when used as special effect makeup on the face. For this reason, it is recommended that liquid latex be allowed to vent for several minutes before being applied in this way. Appropriate liquid latex safety guidelines [1] should be followed before the cosmetic use of liquid latex.”

      I’m not sure if the increased ammonia in the craft liquid latex is also there to promote longer shelf life or if it serves some other purpose. The only other thing I can think of is that most masking fluids contain dyes so that you can see them more easily on the paper. If the cosmetic stuff was white that might make it a little harder to use. It definitely seems like it would be worth a try, though! There are plenty of cheap cosmetic ones on the market. If anything, they would probably be safer to use since they would give off fewer fumes. Let me know if you decide to try it. I’d be curious to hear how well it worked. Thanks for the idea/information!

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