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Help with heat shrink film on rounded fuselages please


Andy C
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I have recent times covered a couple of planes that I have built, so only naturally thought I would this evening cover the fuse of my slow poke with some nice fresh hobbyking red heat shrink film. Hmmmm, not easy is it when the fuselage isn't square. Would therefore appreciate some advise and / or links to helpful youtube videos please before I attempt it again.

Thanks

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I think the key to it is not to try and do too much with a single piece of film. The most-recommended method for fuselages, whether they're square or rounded, is to do the bottom first with one piece, and then over the top and down the sides with another.

I prefer to use an iron, rather than a heat-gun, for most covering, so I would usually start by tacking down the centreline of the bottom piece of film, and then working out sideways with the iron a bit at a time, pulling the film tight to help it shrink neatly round the curves. Having cut it over-size, I then cut the bottom piece neatly where I want the joint to be, before starting the top-and-sides piece, which I also start by tacking it down the centreline and then working downwards with the iron while pulling it tight. I overlap the bottom piece by about 3mm before cutting it neatly. Finally I go over the seams again with the iron.

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It can be tricky, but by giving yourself a large amount of overlap so you can grip the film easily and pull it into shape and with the covering iron sticking and moulding the material onto the workpiece you can make a good job. Excess is simply trimmed away when you're satisfied with the finish. Given patience and working steadily, it's surprising how film can be coaxed around odd shapes. Watch for wrinkles that are too big to shrink out, and avoid them as much as possible in the first place by working a bit at a time and firmly pulling the film into place with the excess that you've allowed. Takes practice but it's not impossible and Hobbyking film works well. As has been said, avoid heat guns as I find you don't get the degree of control that you get with a covering iron.

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Carperfect, your experience with HK film is interesting as I tried a sample of their dark blue film by overheating it and pulling overly hard to try to get some idea of its limitations compared to Solarfilm and Profilm .I didn't get the issue that you found. Obviously a variation in the properties of their films, so worth checking the stuff before starting a job.

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I am about half way through the building process so will be on to covering hopefully soon. Calder Craft Primary.

In the past I have only used tissue so this is probably a daft question but how do you hold the model, pull the film into place and then use the iron with only 2 hands. Is there a 'knack'.

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"Is there a 'knack'."

A prehensile tail is quite useful, as are feet that operate a bit like hands.

Failing that (!) you just have to stabilise things with your knees a bit. It's always awkward.

"not easy is it when the fuselage isn't square"

Can only echo the above advice. Cut oversize, by a good few inches (its not waste if you need it to get the stuff on properly). Tack down the centreline, then s-l-o-w-l-y stretch and stick the film (it will mostly stick by itself if you are stretching it against and around the curved structure), bit by bit by bit, using the iron at its normal temperature. Start at the middle, work outward. Don't rush it, don't use a heat gun, don't turn the iron up. It's amazing what the film will conform to given time, moderate heat and a bit of tension. Even really tight curves. Do use a fresh scalpel to finish up, and blades only seem to cut cleanly for one lump of structure (e.g. the fuselage) before they're a tiny bit blunt and start to tear the film - factor that in, get a new pack of blades, don't be shy about changing blade regularly.

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Posted by Julian Murch on 25/03/2019 08:54:14:

I am about half way through the building process so will be on to covering hopefully soon. Calder Craft Primary.

In the past I have only used tissue so this is probably a daft question but how do you hold the model, pull the film into place and then use the iron with only 2 hands. Is there a 'knack'.

Depends on the shape of what you're trying to cover and its size. For larger components I put some foam sheet (packing material) on my bench top and this both stops the part  getting damaged and offers a certain amount of grip, stops the part from slipping about and by applying a bit of pressure from your arm/elbow/side of hand while working, makes the job more stable. Trying to clamp parts down or using weights doesn't work as you'll always be moving the bits around to get the covering right.

 

 

Edited By Cuban8 on 25/03/2019 12:14:32

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Thanks for all the replies everyone. Must admit though I am struggling to find any good and useful videos showing an actual fuselage being covered from start to finish, including whether to use single piece over top and sides, how to work around the rear stab etc. so any links would be great thanks

Edited By Andy C on 25/03/2019 13:23:17

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Just did a quick look, this guy makes a good job on a fuse but in most cases you will have to look through several vids to get bits out of them that you want, don’t expect to find 1 that gives you everything. I would say that I look for techniques being used that I can use on my own piece of work. Seek and ye shall find.

And here’s another

Link

Edited By Ron Gray on 25/03/2019 13:40:31

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Thanks Ron, but I regard that as an easy one to cover and have no problems there. The Slow Poke on the other hand has a multitude of surfaces in all sorts of directions.

Am I doing it wrong thinking I can cover the whole top and sides of fuselage in one go? The problem is, with a rounded top there is no corner to hide any joins.

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Re one piece for the top and sides - all the ARTF fuzs I have repaired (more than a fewblush) have mostly had a seam in the covering at the top centreline of the fuz or very occasionally separate top side and bottom pieces done in sequence bottom, sides, top. I use a piece of polystyrene foam packing from a microwave oven box to support models while covering - i cut a 'U' channel out of each end so that fuzs sit in it - doesn't damage the covering.

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"Am I doing it wrong thinking I can cover the whole top and sides of fuselage in one go? "

I think you'll struggle.

I would make a seam running along the top of the sides (assuming the sides are flat and the top deck is curved).

You could try making the seam along the top centre, doing one underside piece, and two side/top pieces. But, the taper of the fuselage will make it trickier than using four pieces.

On that basis, I'd go with the usual four piece method, bottom, sides, top.

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