![\"DSC_1019\"](\"http:\/\/www.balsaworkbench.com\/wp-content\/uploads\/2017\/08\/DSC_1019.jpg\")
<\/a><\/p>\nSometimes it’s really difficult and you end up trying a few times.<\/p>\n
Sometimes you have to go at it with a hobby knife.<\/p>\n Once you get the corner loose you can get it off without any further trouble. \u00a0Triumph at last!<\/p>\n Don’t forget to save the big pieces of backing plastic for protecting your plans while you build. \u00a0This is the piece from the bottom of the wing, so it’s the largest piece I’ll get from this plane.<\/p>\n I did the bottom of the wing the same way I did the top. \u00a0I won’t give you photos of the entire process. \u00a0Just do it the same way, tacking a spot in the middle of the edge at the root, then the middle of the tip, then the middle of the leading edge, and finally at the middle of the trailing edge. \u00a0Tack the corners, then all the edges. \u00a0On this sort of wing I would prefer to finish the leading edge first. \u00a0I use the same procedure outlined in the description of finishing the white trailing edge, except that since there is no sharp corner I simply choose how far to iron the film, and I continue ironing the film all along the leading edge to that same imaginary line. \u00a0Then I start again at one end and iron it a little bit farther, and match it all along the line. \u00a0 When I get to the point where I would like to iron it about 1\/4″ farther around the leading edge I cut it off in a straight line.<\/p>\n There is a point to be made about scissors.\u00a0 With some scissors you can snip just a little nick at the end, then push the scissors forward to cut a long line without doing any more snipping.\u00a0 Some scissors won’t do this for some reason.\u00a0\u00a0 Another distinction is that some scissors have a square tip with relatively sharp corners, while other scissors have rounded tips.\u00a0 To zip a long line along the edge of an airplane part for the perfect overlap, you need to glide the tip of the scissors along the edge of the part without gouging.\u00a0 So if you’re looking for the perfect pair of scissors, you want one that has both of these important qualities.\u00a0 Don’t be afraid to try a few different pairs of scissors until you find the right pair.\u00a0 I had a pair that I liked, but I lost it when I moved a couple of years ago.\u00a0 I browsed around in my wife’s sewing room until I found the perfect pair of high performance covering scissors, then I put it in the garage with my covering iron.\u00a0 Don’t worry.\u00a0 She won’t ever notice.\u00a0 She has more scissors than she knows what to do with.<\/p>\n The edge is finished by ironing it all the way down. \u00a0Remember the direction to move the iron. \u00a0In the following photos I am progressing from the top of the photo toward the bottom, and the stroke of the iron takes it from here:<\/p>\n to here:<\/p>\n (I know the white film is supposed to be on the top of the wing already in these photos, but this is a tutorial so I got a few things out of order. \u00a0Pretend the white is already there.)<\/p>\n The corner of the leading edge where it meets the tip can be heated and pulled\u00a0to stretch it over the curved corner of the wing. \u00a0This is where the advice from the folks at Top Flite comes in handy. \u00a0Stretching around this corner would be a lot easier with 2 inches of extra film, but if you want to save some money you can cut it just long enough so you’re able to grab hold of it and pull, which is what I have done here.<\/p>\n As the leading edge is ironed down, with a bit of care this corner can be ironed as well, then trimmed and finished. \u00a0The pre-stretching will help it settle down without wrinkling.<\/p>\n At the tip the film is ironed over the edge, but not across the face of the wing tip, depending on the desired pattern. \u00a0I wanted the line between blue and white to be halfway across the tip. \u00a0So I pulled the blue covering over the tip and marked the center line with a pen at the trailing edge:<\/p>\n Then I marked the center line in the vicinity of the spar:<\/p>\n Then I made a guide line for my scissors:<\/p>\n The excess was cut off, and the film was ironed onto the tip.<\/p>\n Here’s what it looks like with the film ironed down. \u00a0The black smudges are ink from the marking pen. \u00a0They can be removed easily later with acetone.<\/p>\n The corner at the trailing edge of the tip can be finished in the same way that the white one was. \u00a0Slits are cut, the flaps are trimmed to about 1\/8 inch, and they are ironed down one by one. \u00a0Then the trailing edge is finished the same way as the white one, with one exception. \u00a0The protruding film is trimmed with a sharp pair of scissors so it will cover only half of the trailing edge. \u00a0When I look at the wing from the rear I want the edge to be blue on the bottom and white on the top. \u00a0So the scissors are held at just the right angle so they can glide along and cut a strip off, leaving exactly the correct amount. \u00a0The film isn’t snipped. \u00a0The scissors just zip along and cut the film.\u00a0 This is the situation where a good pair of covering film scissors makes all the difference.<\/p>\n So, the complete procedure is to iron the entire line of the trailing edge all the way to the edge of the balsa. \u00a0Don’t leave any spots where it’s not attached. \u00a0Then trim the protruding portion. \u00a0Then the remainder is ironed down along the trailing edge. \u00a0Here’s what it looks like after it’s ironed down. \u00a0Half of the trailing edge is blue and half is white.<\/p>\n The only other important part of this wing is the top blue piece. \u00a0This piece requires a bit of extra care because of the line that will be visible between blue and white. \u00a0Some guide lines are needed to assure that the line is straight. \u00a0I’m using the edge of the balsa because I know that the plane was built straight, and the balsa is clearly visible through the white film. \u00a0If you want the dividing line elsewhere, or if you know your balsa isn’t straight, you can mark your chosen location with a pen.<\/p>\n This piece can be tacked at the two corners that form the straight line against the white, but I prefer to do it exactly as the other pieces, by tacking it in the middle of each end. \u00a0In my experience, tacking at the corners first leads to a curvy line.<\/p>\n The film is laid out in the correct location, one end is tacked, then the other end is pulled flat, making certain that the edge is located at the correct position on the target line. \u00a0Then the second end is tacked. \u00a0The edge will wrinkle and pull away from the target line.\u00a0 (In the following photo you can see that my iron was too hot, causing the film to shrink while tacking.\u00a0 This is because the blue is Chinakote, and the white is Monokote.\u00a0 Chinakote has a lower working temperature, so I should have adjusted my iron after finishing the white parts.)<\/p>\n Then the center portion of the edge that forms the blue\/white division along the spar is gently pulled into place. \u00a0Notice that it is not stretched excessively. \u00a0It’s just pulled flat and placed where it belongs.<\/p>\n Then it is tacked with the iron.<\/p>\n Then the first corner is pulled\u00a0into\u00a0line.<\/p>\n This corner is then ironed into place.<\/p>\n This process is repeated at the other end.<\/p>\n Then the remainder of the line is ironed down, with extra care to avoid distorting it. \u00a0After the entire blue\/white dividing line is secured, then the center of the leading edge is pulled out and tacked.<\/p>\n The hard work is done. \u00a0Now the rest of this piece is finished just like the others. \u00a0The film going over the end at the tip is heated and stretched just as the white film was, to make it lie flat against the flat face of the wing tip. \u00a0And if there is enough protruding film to grab onto, the corner can be heated and stretched, then trimmed and ironed down without a wrinkle. \u00a0Here’s what the wing looks like with all of the covering attached.<\/p>\n Note that I have not shrunk any wrinkles out of this wing. \u00a0So far I have only stuck the film on, and I’ve tried to make it as flat as possible by pulling it into place and stretching it around corners where necessary. \u00a0If you are relying on the film to shrink to get rid of wrinkles you’re doing it wrong. \u00a0You’re supposed to put the film on without wrinkles, to the extent that you possibly can.<\/p>\n Next I’m going to give it a going-over with a heat gun to tighten everything. \u00a0First I need to provide an escape path for heated air. \u00a0A T-pin is stuck through the wing tip to make a small, inconspicuous hole.<\/p>\n Here’s the hole with the pin removed.<\/p>\n Here I am blowing a heat gun at some little wrinkles. \u00a0None of these wrinkles are serious. \u00a0They’re just minor blemishes.<\/p>\n This can also be done with an iron. \u00a0Sometimes it helps to turn the iron temperature up a bit for this step so you’re not there all day trying to tighten your film. \u00a0If you are using a heat gun, be careful not to burn a hole in your film. \u00a0It’s a good idea to recognize when this is about to happen, so I would suggest making a 3 x 3 inch square of balsa sticks and covering it with whatever film you are using, and go ahead and blow a hole in it just to see what it looks like. \u00a0I’ll provide a photo sequence of tightening, and then overheating a test square in Part 4<\/a>.<\/p>\n And here’s the finished wing.<\/p>\n In Part 3<\/a> I’ll talk about how to cut out patterns and cover a fuselage.<\/p>\n","protected":false},"excerpt":{"rendered":" Part 1 was about putting the first white piece on top of the wing. \u00a0It’s a good idea to do both white pieces before applying any dark pieces\u00a0because it makes it easier to line the joints up in the middle, … Continue reading 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