It's not likely that your model will melt but quite possible that your paints will turn to goo. While it's possible that SOME lacquers, applied SPARINGLY over SOME acrylics can work fine, you'll need to ask yourself if your model is worth the risk. Suggest you try it on some spare parts that you won't use or on an old model that can be used as a "mule" before using your model as a guinea pig