Shawn beat me to it here. I gave up on hobby shop minute epoxy years ago. The quality is too poor and inconsistent, and the resin is thickened with some form of filler I can not identify. I use laminating resin, and will thicken it with silica, microballoons, carbon nanotubes or milled fiber as the application requires. The initial cost is higher than tubes of minute epoxy, but you will never look back. My go to resin is US Composites 635, but there are plenty of quality resin systems available. I will caution against the use of West Systems resins for aircraft use. They are a very high quality resin made for marine use and therefore remain quite flexible when cured.

Scott