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Building Tips and technical articles. => Building techniques => Topic started by: John Watson on July 28, 2019, 09:34:03 AM
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Covering wingtips with monocoat is a chore. Whats the best way to get a quality finish on tips?
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Covering wingtips with monocoat is a chore. Whats the best way to get a quality finish on tips?
Lots of heat, and lots of tension. It will go around corners and compound curves to a remarkable degree, but you have to work it and really pull.
Brett
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Covering wingtips with monocoat is a chore. Whats the best way to get a quality finish on tips?
I cover the tip and the wing in two separate processes. I cover the tip before I cover the wing which allows me to "cheat " the tip covering by managing both the outboard and inboard edges of the tip covering. I use at least an inch of overhang on both the inside and outside edge so I can grab the covering and work it better. I then cover the wing. You can always use a wider cap strip on the last wing rib to give more surface area to work with. The seam created by the overlapped covering is almost invisible, but I usually have a paint scheme that covers that area anyway. I use a light coverage of primer under the paint and the sanded area completely hides the seam. I just used this method to cover a Combat Streak wing (which is an impossible wing tip to cover) and it worked well.
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Leave a lot of extra 'coat around the seam, so you can grab on to it (at least an inch). Get the 'coat stuck down around most of the wing, up to the tip. Wear a glove on your left hand (well, non-dominant hand) and grab the heat gun your right. Then pull it out and heat it and pull it down. When it's hot it'll stretch as well as shrink, so you can get it pulled around some pretty complicated shapes.
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On the general topic of iron-on covering, I learned a lot from this book:
https://www.amazon.com/Toms-Techniques-Tom-Ingram/dp/B00071NIUQ
although I wasn't able to implement it to the remarkable degree Tom did it!
Brett
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this is a brief explanation and a short video how i do it (link on the end for the pics and video). Works the same with Monokote/ultracote/oracover. Never used other brands and i strongly recommend one of these top brands.Pricey but will last forever and achieve better results. First use the iron to tack seal the LE/TE and center covering, no need to complete seal, just tack to hold the covering. Then with the heat gun you gently lift the covering from the wingtip and blow hot air close to where you hold it until changes colour and you feel that the covering softens, then pull down towards the outer perimeter of the tip, nevermind to straight the wrinkles on the top yet. the goal is to pull it and adhere a smal portion at time. move to the next 2" portion and do it again, sometims you will need to soften an already glued edge to help tightening, you can lift back the covering a few times (make sure you have sanded the balsa with 400 grit sandpaper and completely dust blowed before). go ahead doing small portions until the LE, make sure you pull the covering about 1/4 after the center of the tip, so you can trim it later and have 1/4 overlap. when finished, trim the extra at least 1/4 past the center line. DO NOT tighten the covering yet, proceed with the top side of the wing, and after that only you can use the heat gun to taut the whole wing, starting with the wingtips. hint: do not blow over the seam, instead, point the heat gun from center of wing to tip, otherwise you will release the glue
https://www.facebook.com/Fredcesquim/videos/1409785155718783/ (https://www.facebook.com/Fredcesquim/videos/1409785155718783/)
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finished wing tip
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Covering wingtips with monocoat is a chore. Whats the best way to get a quality finish on tips?
Covering wingtips with monocoat is a chore. Whats the best way to get a quality finish on tips?
Everything except the engine pit on this ship is monokote, even the wheel pants and nose and tail trim. The trick is to cover the curves with a different piece than the flats and keep stretching. A trim iron comes in real handy when doing the wing/stab fuselage joint, etc. Don't ever let it cool with a wrinkle. Almost anything can be covered with enough patience. Inside curves need to be done very slowly and worked from the center out. You have to be real careful when you put the main covering on that you do not hit the joints with a heat gun. I use gobs of balsa-rite on joints. Try and keep smooth sanded bare wood wherever possible. It sticks better and you don't get bubbles. If you are going to use multiple colors put dark over light on the overlaps. White will show through even if what is under it is white. Plan your seams around your trim and you can do really nice finish. This one got 16 finish points at one contest and I am not even close to as good as some of the monokote experts.
Ken
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Bob Barons on about exactly that , here . or the tape before if not .. Link :
https://www.youtube.com/watch?v=b4fZ6pal-o0
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this is a brief explanation and a short video how i do it (link on the end for the pics and video). Works the same with Monokote/ultracote/oracover. Never used other brands and i strongly recommend one of these top brands....
That looks exactly how I do it, except I wear a glove on the hand grabbing the 'coat. You must have fireproof skin!
The cheaper covering works essentially the same, only with more frustration. So does the super-light good covering, for that matter.
Be sure not to get a fold in it when you stick it down (I suspect Fred knows this already)
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That looks exactly how I do it, except I wear a glove on the hand grabbing the 'coat. You must have fireproof skin!
The cheaper covering works essentially the same, only with more frustration. So does the super-light good covering, for that matter.
Be sure not to get a fold in it when you stick it down (I suspect Fred knows this already)
Donīt you love barbecue fingers Tim?
actually i have been cheap and cut the covering short, so no room to grab with gloves, but you can tell itīs burning as i have to let it go fast.
and yes, when they fold and stick, thereīs nothing you can do to save the finish ( there it goes a new roll of monokote...)
regards from Brazil