We have been painting custom bikes for years, this is a must use if you are doing multiple layers. This is the product you should use. We also use it when doing on cars also. An example is when you're doing racing stripes and need something that will protect it during the masking and taping. This is a great product for doing art work this will seal your art work as you build up the layers. TCP is a great supplier and ships it out super fast and the price is much better than your local shop prices.