Debbie Travis Vs. Liquitex

I love going to the art store but I hate paying art store prices for small bottles of "liquid gold". As a result I'm always on the hunt for "alternative" materials. There's been a lot of debate and misinformation as to whether or not acrylic house paints and their brethren can be used to produce quality art work. I hope the following will show there are limits to what materials designed to paint houses can do compared to artist quality materials. Although, as I also found, you may be able to get away with using materials from the hardware store in certain situations.
The story begins with a trip to the paint counter at Canadian Tire. I noticed that the "Debbie Travis" (of Home & Garden TV fame) paint line had quite a few items in the clearance shelf. A can labelled "Venetian Plaster" was the one that first caught by eye. I had the clerk shake it up so I could have a look. To my surprise it looked and smelled very similar to Liquitex's Flexible Modelling Paste. The big difference was that a pint of Liquitex FMP is well over $30 and same amount of the Debbie Travis material was only $10 (on sale)! Worth a try.
Observations/
Colour: The Liquitex material is not completely opaque and has a beige colour very similar to raw canvas while the Venetian Plaster was very white in comparison. I'm guessing that the makers probably add a lot of chalk or similar calcium mineral as filler to make it appear similar in nature to plaster of Paris. Viscosity: they are both highly viscous, that is to say, thick and buttery, although I'd give a slight advantage to the Liquitex material. Dry Time & structure: Both were dry to the touch within about 45 minutes to one hour, thicker areas took longer to completely cure. Feel: both had an impasto medium feel to them and held their form well, my intention was to use them as texture layers as part of the underpainting so I have no idea what happens if you mix paint into either (probably a big mess).
Testing\
My first test was to just spread them out of different materials to see how they performed. Test one was knifing out a bit of each onto a paint stick to watch them dry. I put a little pattern in to each and varied the thickness. Mostly this test was about establishing dry time. Test number two was to see how they did on canvas material. I spread a little bit of each out similar to the paint stick test. The Venetian Plaster seemed to curl the canvas a bit more as it dried but there may be other reasons which explain what I saw. No I'm probably in denial, it had to be shrinkage, a little bit at least.

After each swatch was completely dried and cured (12-24 hours) I used a knife to scrape each surface to check for durability. The Liquitex could be cut and carved. When I did the same test on the Venetian Plaster it reacted much like real plaster does it kind of crumbled and flaked. Fingers were powdery after handling it. The most damning conclusion is when I tested the canvas swatches. The Liquitex just bent like dried bubble gum while the Venetian Plaster cracked and flaked.
Conclusions\
I had done similar tests comparing acrylic house paint primers to Liquitex Acrylic Gesso. The house primers varied in flexibility some worse than others but clearly Liquitex is using a formula which allows their products to bend without breaking -- something not only desirable but also completely necessary when painting on canvas. This is not the normal concern of a house painter because they mostly they paint solid supports (read:wood). This is probably the only place that Ventian Plaster has a use, painting on board. So if, and only if, you're do work on masonite or panel it "might" be a bargain. Then again it "might" just flake off after 20 years once the guarantee has expired. For some cheap fun and classroom experimentation it might be worth trying but for the keepers stick to using something a little better than the Venetian Plaster. ~m