How can I make my own masking fluid or rubber cement?
There is a way to make your own masking fluid at home. If you are using the masking fluid for watercolor paint I need to warn you that over time homemade masking fluid following this recipe can cause your paper to dissolve over time. You will need some rubber cement and some nail polish remover. Empty about 1 to 2 tablespoon of rubber cement out of the jar so you can leave room for the nail polish remover. Now fill this with the nail polish remover and take a paintbrush to start mixing it. Now you apply the masking fluid to a piece of paper and allow it to try. You will notice that the color of the masking fluid has a yellow tint to it. This is because of the nail polish remover you have added to the rubber cement.
First, pour equal parts of cement and water into the container. Next, dip a wet brush into a water color paint, then into the container.
Keep dipping until the color of the masking fluid is satisfactorily dark, or the masking fluid will be clear and difficult to see on the canvas.
This is not a field I'm familiar with but after researching I also feel there are some things that maybe should not be 'homemade'.
If you are a beginner then I would suggest you do some research on this subject and you may find better/different ways to accomplish the effect you're looking for.
There seems to be a tremendous amount of YouTube videos on this subject but after watching several it seems these teachers are the most thorough and easy to follow.
How to use Masking Fluid
Masking Fluid tips/tricks
Making Fluid alternatives - I like this one - simple/great ideas
These links are not really answering your question but if you are just getting into painting maybe one of these will give you some new ideas.
I agree with the recipe of mixing latex fabric cement and water, and stirring it up. The recipe is at the following link: