So I had to get a pair of those patches with the new USA logo to cover the old logos on my fencing pants. The instructions say that they can be ironed on to hold them in place in addition to sewing them on. I will be sewing them down, but the instructions do not say what heat to use. I don't want to melt or burn them, or the pants, but usually iron-on patches use high heat. Does anyone know how to do this safely? The pants are Uhlmann FIE, vintage 2004.