Read the label on your orange paint! They will almost always have a recomendation for a clear layer.
In general, the clear that comes in spray cans is lacquer (dries very fast) and because of the solvents used, can lift and ruin many finishes... especially spray can enamel! So, pay attention to the label and stay with a compatible clear.
Automotive urethane usually will not adhere to rattle can paint and will lift in sheets some time in the future. I say usually because there are exceptions. Read the label.