planking or sheeting?
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planking or sheeting?
This is my first real scratchbuilt, I planned the structure from a 3-view and some cross sections, now I would need your suggestion on which would be the best technique to cover a structure like this. Planking ( 3mm) sounds like a really hard job and most probably the fuse will end up being heavy, if sheeting over sharp curves I should use very thin balsa (1,5-2mm) and that sounds easier but fragile.
thank you
david
thank you
david
#4
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RE: planking or sheeting?
I remember building an Me-109 kit in 1953, in Germany! It used sheet instead of strips.. as the contours of the fuselage are close to straight lines.. but the slight curvature does create a problem.
Soak the sheet in a solution with ammonia.. this will loosen the fibers in the sheet.
Place the wet sheet on the structure and let it dry.
It will conform nicely to the fuselage.
Then glue it in place.
Gluing while it's wet is messy and can create bulges as the sheet dries.
Soak the sheet in a solution with ammonia.. this will loosen the fibers in the sheet.
Place the wet sheet on the structure and let it dry.
It will conform nicely to the fuselage.
Then glue it in place.
Gluing while it's wet is messy and can create bulges as the sheet dries.
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RE: planking or sheeting?
Something we are doing a lot of is molding the balsa sheet wet over a form, letting it dry, trimming and gluing to the structure. Either 3/32nd sheet, or two layers of 1/32nd with CF veil between..lots of ways to go. Cut your forms out of hi-density foam and add "bottom" of 1/2" plywood to give some oversize. Soak the wood in hot water, bend around, and wrap with an Ace wrap or even old rags. Let dry 24-48 hours. Pick some good light (5-6 pound A grain balsa). BTW, 3/32nd is probably strong enough for what you have in mind. The molded shape is both strong and light.
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RE: planking or sheeting?
Molding the balsa is GREAT... IF you are making a few copies. The problem with a one-off is you go to all the trouble of making the plug to mold the balsa around and never use it again.
There is a technique that is between molding and planking... you soak the sheet and bend around the framework... where it tries to wrinkle...you slice out long thin triangles. You get a lighter fuselage than true planking (less glue) and it goes a lot quicker.
When doing these... use yellow glue because the working time on soaked balsa is... all day.
****
Also.. the joints of yellow glue sand smooth easier than CA joints
There is a technique that is between molding and planking... you soak the sheet and bend around the framework... where it tries to wrinkle...you slice out long thin triangles. You get a lighter fuselage than true planking (less glue) and it goes a lot quicker.
When doing these... use yellow glue because the working time on soaked balsa is... all day.
****
Also.. the joints of yellow glue sand smooth easier than CA joints
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RE: planking or sheeting?
thank you!!!
well..I will definitely opt for 3/32" sheeting! The molding method sounds like a very accurate one, but in this case (making just one fuse) I'll wrap the soaked balsa directly over the structure.
Would an ammonia solution work better than plain water? Which percentage of ammonia is needed? Should I use gloves or some kind of protection with ammonia?
well..I will definitely opt for 3/32" sheeting! The molding method sounds like a very accurate one, but in this case (making just one fuse) I'll wrap the soaked balsa directly over the structure.
Would an ammonia solution work better than plain water? Which percentage of ammonia is needed? Should I use gloves or some kind of protection with ammonia?
#9
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RE: planking or sheeting?
I have heard it said that ammonia is not necessry for balsa and water will work well. I have used water or windex with good results. I make .40 -.60 sized warbirds and have learned to use 3/32" sheeting over open frames instead of the 1/16 sheeting. It is stronger and can be sanded more to smooth out seams.
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RE: planking or sheeting?
The one in my avatar is blue foam covered with 1/16 balsa, soaked in the bathtub for 10 min. and wrapped with the bandages. took them off the next day as the bandages are fairly porous and dried out fairly quickly. 25 FX up front.
#11
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RE: planking or sheeting?
"Windex", "409"... contain a bearable amount of ammonia. I use what's closest to hand when I go looking for some..Getting the wet sheet nice and floppy and letting it dry on the form is what's important. You can cheat with a heat gun..
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RE: planking or sheeting?
Also I glue the sheeting on with yellow wood glue with a hypodermic glue gun in a zig zag or saw tooth pattern. No need to cover the whole thing with glue as it adds a lot of weight.
#15
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RE: planking or sheeting?
I did a 62" ws 109 some years back, my design. The whole fuse was strip planked. Looks terrible until the sanding is done. Strip planking is easy and I use it mainly when there are a lot of compound curves to deal with. I use pins mostly to hold it down, and it goes faster than you think. You wont notice any real difference in weight, it'll still be pretty light weight. I'll use a sanding bar with 80 grit sand paper on it for the first pass sanding. Then use spackling to fill in imperfections and sand again. Sanding goes real fast no problem.
Edwin
Edwin
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RE: planking or sheeting?
[]I think I have a problem!!... balsa sheet looks collapsed between the formers, like it shrinked! uhmm... any solutions out there?
thank you
thank you
#18
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RE: planking or sheeting?
You probably have too much space between the formers, and you might try again with thicker sheet balsa.
Wrap the wet wood loosely to the formers and stringers to let it dry first. Then trim to fit and glue.
Doing it all at once leads to this kind of problem, as the wrapping pulls the wet sheet into the unsupported areas between formers.
Wrap the wet wood loosely to the formers and stringers to let it dry first. Then trim to fit and glue.
Doing it all at once leads to this kind of problem, as the wrapping pulls the wet sheet into the unsupported areas between formers.
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RE: planking or sheeting?
Two thoughts here - I observed kind of the same think when I sheeted my wing. Instead of the bandages, which apply pressure over the entire area, use masking tape next time, and only hold down directly over the formers. That's, of course, more of a "next time" thing, unless you can get the sheeting back off...
Perhaps, to fix the sheeting in place, just wet it, support it upside down, and maybe fill it with something like sand to balloon it out a little?
Dan.
Perhaps, to fix the sheeting in place, just wet it, support it upside down, and maybe fill it with something like sand to balloon it out a little?
Dan.
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RE: planking or sheeting?
I'm a bit suprised nobody suggested using the thin hardwood sheeting. (the proper name escapes me now) Ya know the stuff thats like 1/32" thick.
I used this once on a tank compartment top and loved it.
Bent real easy and was tougher than balsa.
Man I am really drawing a blank on the name of this stuff...[:@][:@][:@]
I used this once on a tank compartment top and loved it.
Bent real easy and was tougher than balsa.
Man I am really drawing a blank on the name of this stuff...[:@][:@][:@]
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RE: planking or sheeting?
I saw a link to a woodworking outfit that sells obeche. Now where in the heck was it????? I'll keep an eye out for info's sake.
Kelvin
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ORIGINAL: Tall Paul
Obechi is probably the name.
Mostly found in European kits.
Can't recall seeing any loose here.
Obechi is probably the name.
Mostly found in European kits.
Can't recall seeing any loose here.
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RE: planking or sheeting?
David, that's why the form method is better. You may get some sagging when the covering is applied, but less than you got. BTW, cutting a plug from blue construction foam is pretty fast and easy. A pattern on each end lets you either hot wire it, or even use coarse sandpaper to shape the form. Really doesn't take too long.
ORIGINAL: David74
[]I think I have a problem!!... balsa sheet looks collapsed between the formers, like it shrinked! uhmm... any solutions out there?
thank you
[]I think I have a problem!!... balsa sheet looks collapsed between the formers, like it shrinked! uhmm... any solutions out there?
thank you