Greetings, I just tried a product called VMS Liquid Mask, and I have to tell you that this is a masking product I had wished for for a long time.
What I like:
1. It flows nicely. (It's NOT self-leveling). What I mean is that you apply a drop on the piece, and it holds its shape. Then, you take a paintbrush or whatever and move it around the areas that you want masked. You can get into nooks and crannies, and the liquid creates a thin masking layer. It works great to flow along demarcation edges. It is very easy to apply, and it dries in about a half hour. Also--I did not see any evidence of the mask pulling up paint. In my test I had used Alclad so, "maybe" that could change with other paints? I suppose like with any mask the more paint you apply, the more risk of fracturing.
2. The mask comes off the piece in relatively large sections. I did need to pick some areas with a hobby knife, but they came off easily. I think if I had applied a thicker layer it would have come off better. Either way, it worked very well.
In the example below I had masked the base and painted the tank. This worked great for flowing the mask under and around the tank assembly.
I purchased the product off Ebay. The supplier that I went with ships from Poland. It took about two weeks to arrive in my area, Stateside, but the Post Office bungled some things delaying it another week. I suspect that it will be more readily available in the States sometime soon. I noticed Michigan Toy Soldier & Figure is carrying the VMS line of products. This can be purchased through them, though, it does not look like it is in stock.
Is it perfect? No, but, it is dang close, and it is the best liquid masking product I have used.
Two things I should mention. They say the mask should be removed in WITHIN 24 hours. Secondly, they say to use a brush. Just a heads up that you should use a brush you don't care about because it mucks the brush up bigtime. I will probably switch to using toothpicks, or maybe even a hobby blade.
Below is a video telling more about the product.
https://www.youtube.com/watch?v=P9iAs3_oFJI