I would be careful here... That USC quickens quick . .let it dry overnight.. ,it takes time for rhe MEQT ( the clear stuff ,in the tube) to catalyze. Just personally, experience.
Yeah mixing either of the aluminum based fillers is tougher than typical Bondo because there’s no color change. So it can be a bit harder to get the right amount of hardener and a good mix. Too much and it sets up super fast, too little and it takes forever. And either way it looks the same when you’re mixing it. Takes some practice, especially if your air temperatures are very cold or very hot.
