Here are the opinions I have on my Finishes
page for Minwax:
... high gloss, smooth finish
...I started a test of minwax polycrylic to see if it would work as well as Varathane .... I suggest you stay away. It does give a nice gloss finish but it is not as strong and scratches easily.... Bonnie
...I find that the Minwax product is a little shinier....even the Satin has a fairly high sheen unless it is applied very lightly.
.......II have bought small quantities (half pint containers) of Minwax at Sears and at Walmart. Lizzylady
...After baking it looks good - no blistering. I also dipped a heart - it looks great. The fine lines that were visible before have disappeared. . . . The label on the can states that it may yellow, but this doesn't seem to be a problem so far. I didn't try it on white. Bonnie
.....I used Minwax Gloss Polycrylic and put the beads away in a drawer for 3 months. The temp in the room averaged 85 degrees. They all got sticky. When I finally got the Varathane, I did the same thing and put them in the drawer below them and they are still fine. Debbie (NM)
...mine isn't tacky. I have never found Varathane so I can't compare it. I am happy with the Minwax. It's a water clean up one too. Sally
...I use Minwax Polycrylic to finish all my polymer clay. I can notice a difference in tackiness on humid days.... so I never, ever rush applying the coats & I always allow for the recommended time between coats, and usually allow even longer than recommended.
......the tackiness I have noticed has always gone away in time though , without any noticeable change in the finish. Sue
So I'd say that there are a few main differences between Varathane and this brand of clear acrylic finish:
...no UV protection (so could yellow over time)
...no IPN (interpenetrating network), which allows the finish to sink into the suface of the clay rather than sitting on top of it
...may be more susceptible to tackiness in humid times (esp. if applied too thickly, or not allowed to dry thoroughly between coats)
be more scratchable on the surface
All clay acrylic finishes (liquids--in cans or bottles) are basically "compatible" with polymer clay, but some types or brands may have a few disadvantages.
All the ones I know of are discussed on this page if you want to check them all out (and also see some other places you might be able to buy Varathane):http://www.glassattic.com/polymer/finishes.htm
P.S. the smallest container that Varathane comes in is
a quart; that's the size clayers are usually looking for, instead of the gallons which are also sold (although some art or clay suppliers may sell it in smaller quantities)
.... just do as others do and pour some Varathane from the quart can into a smaller air-tight container (baby food jar, or whatever), then use it from there until you run out (or it's thickened too much from sitting unclosed, etc.)