what covering film are you using? give us a point of reference so that we may be able to offer better help. For me, Iwas a die hard Topflight Monokote user until about 3 years ago. They changed the formula on the film which made it terrible to use. It didn't stick like it use too. Ironing it on took a lot more effort and it didn't shrink down like it did several years ago. Iswitched to UltraCote and been having decent success with it. Here is a link with some helpful info on how to apply the covering material: http://www.horizonhobby.com/products...t-blue-HANU954

Patience is the key and have some very sharp blades. It is common for me to have three Xacto knives out. First being the most dull which is used to cut the material from the roll. Many times I'll have the covering material rolled out on the building bench and will just cut what Ineed from the roll while it is laying flat on the table. This dulls the blade pretty quick. The second knife is used for cutting the excess material from the surface that is being covered. This is generally done to lop off the excess without too much concern about the seems. Then finally my third knife which is usually a brand new blade and as about as sharp as it comes out of the wrapper. This knife is used to trim the covering down to its final clean edges. having a very sharp blade makes all the difference. Cutting the material should happen without any drag being felt from the blade. if there is drag will cutting the material, then the blade is actually tearing the covering rather then slicing. When I cover a plane Iwill usually go through about 10 to 15 blades. But I rotate them through... going from the third knife always being the sharpest and rotate 3 to 2 and 2 to 1.