I've used clear silicon between the hinge line without any problems,if the hinge line is large then the silicon might fall out with time or add too much weight,the silicon is very flexable,I use the silicon instead of.I cover the complete hinge line on the bottom to keep the top clean,on the rudder I usually seal one side only,what ever sealing material I'm using,except tape,. I'll iron down on the leading and trailing edge of the hinge lineLast year MinnFlyer had a drawing on sealing the line with iron on material,do a search or drop him a line for pictures..