I use Micron pens for my rods without any problems. How are you applying the varnish? Maybe the finish wasn't de-glossed before signing? My technique is to rub some 0000 steel wool where I am going to sign to take the shine off, wash it down with Dawn and water, sign then dip. If you are using a brush for the varnish, give the ink a few hours to dry and use a sable brush to give the signature area a very light coat and let that dry before doing the rest of the rod.