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Building Tips and technical articles. => Building techniques => Topic started by: Jerry Rauch on May 23, 2010, 06:29:22 PM
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Did I just pull off a bonehead move....I covered a Sterling Skylark wing with silk, even went as far as 5 coats of Sig clear, looks great, and then realized I didn't put in any right wing weight or a weight box. Duh.....I'm an idiot....I can't see cutting a hole in the silk to add the weight, since my last attempt at patching silk on my Thunderbird looks like pure hell. I guess there is nothing else I can do. I even thought about trying vel-cro stuck on the bottom with 1/2 oz. of lead, but that doesn't seem very safe. I'd hate to see someone get hit if the weight came off. Any ideas???
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It aint pretty, but go to a tire shop and buy some of their stick-on weights. They come in strips with 1/4 ounce scores and once you put them on they will stay. Some acetone around the edges will remove if necessary. Just stick them on the bottom of the wingtip.
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I can't see how anything you could scab on to the outside of the thing would look better than a patch. Maybe you just need to bite the bullet, cut into all that nice work, build your weight box and patch it up?
Could you put a weight box way out at the tip, where there is (I hope) some solid balsa?
Could you cut a rectangular hole into the silk at the intersection of the bottom spar and the outboard-est rib, then build a weight box up to the back of the hole? I.e. build it inside out so that when you're done it's what you would have if you'd done it that way from the start?
You could always duct-tape some solder on after you get the plane all finished, and try to convince people that you meant to do that...
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It aint pretty, but go to a tire shop and buy some of their stick-on weights. They come in strips with 1/4 ounce scores and once you put them on they will stay. Some acetone around the edges will remove if necessary. Just stick them on the bottom of the wingtip.
That will look worse than the silk repair. Mu vote is to bite the bullet and put in a tip weight box. It's a lot easier to fix now than it will be to later.
Of course this from a guy who won the NATs with a week-old airplane with a big ugly chunk of wheel weight stuck to the fuselage.
Brett
p.s. Tim and I are not in personal contact, identical phrasing is just a coincidence...
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Another vote for cutting and patching. Unfinished junk stuck on the outside will just make it look like an R/C plane. ;D
I say just go ahead and fix it right, any of the cosmetic issues will be on the bottom anyway. Enough repetitive clearcoats and sanding on the repaired area and you should be able to get it looking pretty decent. Patience. y1
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I agree with the repair. I accidently poked a hole at the outer most bay of a silk covered ship. The silk is stuck down tight to the ribs & framework so when you cut leave about 1/8 " to the inside of the bay...make/install your tip weight box & lightly scuff the dope on top of silk and put a patch overlapping at least 3/4" and seal dope as before and as you add dope layers, sand the edges of new silk and I'll bet you will never see the patch once paint has been applied. Tearing the edges of the silk rather a scissors cut will make it blend much better. Good luck !
Geno
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The more obvious solution is; drill a 1/4" hole in the L.E., near the wingtip. Epoxy a 3-4" aluminum tube (with one end crimped shut) allowing about 1/8" sticking out. Fill the tube with b-b's (from your 12ga. shotgun shell) and plug with a balsa stopper. No need to disturb the silk covering!
Floyd
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The more obvious solution is; drill a 1/4" hole in the L.E., near the wingtip. Epoxy a 3-4" aluminum tube (with one end crimped shut) allowing about 1/8" sticking out. Fill the tube with b-b's (from your 12ga. shotgun shell) and plug with a balsa stopper. No need to disturb the silk covering!
Floyd
You could carve and paint a nifty bullet-nosed stopper that would look like a scale detail.
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Model I am working on has the opening for the weight box on top of the wing rather than on the bottom. I'll have to figure out how to make it look like I did it on purpose. HB~>
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I did that too on my Akromaster. I just bit the bullet and moved it to the bottom, glued to top onto the top of the tip and filled it in. It probably just reduced the weight I need to put inside!
Jim Pollock n~
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I like the idea Floyd Carter came up with... going to drill the hole in the outer leading edge at the wingtip. It will be a lot easier to repair a 1/4" hole if I cover the end, or I may put a plug the fits tight in the tube. Thanks Floyd....I would never have thought of that!!
I can't visualize a thing, but I can sure copy other peoples ideas! Thanks again.
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one more possibility if you can do a 1/4" hole, get a brass bolt and screw it in the hole. Change weights by changing the bolt length. If you want to be really sexy, cut the head off the bolt and file a screw notch in the end so you can screw it in all the way flush. Paint the end to match your colors. Brass is denser than steel, that is why it is the material to use.
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I would cut the silk and put in a weight box. As has been said, you will find that silk, unlike silkspan, will not wrinkle around the hole you cut. If you just want to add weight, go ahead and cut the silk enough to get some weight glued in, and recover the hole, and then cover that with a decal. I keep lots of decals of different sizes, to patch things. Sometimes easier than patching doped silk.