Doesn't help much after the fact, but I've gotten really tired of minor tail surface warps and have been reducing them lately. Although I use iron-on, the susceptibility is still pretty much the same. I'm convinced that a number of them came from tissue pulled in even the slightest angled direction, versus perfectly span wise or chord wise across the part. I'm also trying to apply both panels using exactly the same scheme now, like a mirror image, which seems to help. Start at the same place on either side of the panel, and work across the panels, tacking the covering in the same order/same areas. I also now do not fully shrink the first covered side or apply it as tightly, until applying the second, and then shrink both gradually. I realize tissue is a bit different, but the natural tendency is that the last side covered tends to be applied more tightly than the first side which encourages warps, if the covering is stretched at all while sticking it down. I imagine folks using tissue covering use the same techniques, as there's even fewer shrinking options with tissue than iron-on. With tail surfaces, who knows why some decide to warp at times, but with wing panels the procedure has really made a difference. Worst case scenario I've cut through the covering only in a spot where there is framing underneath, to reduce a warp. You can usually find a spot in the framing where the warp starts, and straighten that area. Flex the area with the relief cut just made to straighten the part, and then hit the area with a drop of thin CA. Unlike Louie's apartment on Taxi, after Jim stayed there, It's barely noticeable.
davidchoate wrote:Like Mitch said depending on how bad and where you are at with the finish; You may have to recover it. If it is not rubber power that companies planes need to be reinforced a bit. I have been using microlite because I never really did until recently, and it is so easy to get out warps and get perfect washout with that stuff. I have had to wet and clamp (as Mitch described) tissued parts for weeks before to get them right.
You'll find over time that you have to overkill the warps in the opposite direction with Microlite, as they'll come back on you, especially if it's in a hot area or direct sunlight, but eventually they stabilize and get better after a few reshrinks. I've had a few models where I'll simply tweak the covering a bit, right before taking them out to fly.
