sanding question

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sanding question

Postby Mustang621 » Tue Feb 22, 2011 9:44 pm

Just wondering how much sanding should i be doing? I sand all the stringers flush to the formers, sand the wing so none of the ribs extend passed the edges and then sand it (start by trimming with knife) so that the ribs blend into the leading/trailing edges. After that I coat with 50/50 elmers glue water let it dry give it another quick sand job and then start my tissueing. Is that enough? Seems like its good to me but i am a newer builder.
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Postby Xanadu » Tue Feb 22, 2011 11:16 pm

Sounds like you are on the right path, and have it figured out.
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Postby SteveM » Wed Feb 23, 2011 9:06 am

I'll often leave the stringers proud of the formers a little or even scallop out the former between stringers. The reason being that if the stringers and formers are at the same height then the covering will adhere to both and make little rectangles all over the place.

That's really personal preference, but what you really want to avoid are stringers and/or formers of different heights or formers that stick out past the stringers. You'll often hear this look referred to as a "gaunt horse" because even after covered you can see the bones poking through everywhere.

Here is a scalloping example from my 500 series P-51. Click on a picture to see it close up. http://www.virtualaerodrome.com/image_b ... &offset=24

Here is another of my kits that was not scalloped, but the stringers stick out past the formers pretty evenly everywhere. This was a laser cut kit so getting even stringer height everywhere was easy. Note the little rectangles formed by the formers and stringers. http://www.virtualaerodrome.com/image_b ... &offset=12

I'll see if I can find a "gaunt horse" picture in such a way that doesn't embarrass the builder.
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Postby SteveM » Wed Feb 23, 2011 10:29 am

Ok, a few links on the gaunt/starved horse look.

http://www.modelflying.co.uk/forums/pos ... p?th=32500 (pictures with post dated 02/10/2009 08:48:49)
http://www.rcgroups.com/forums/showthre ... st12478066
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Postby Mustang621 » Wed Feb 23, 2011 11:01 am

Thanks for the tips. In terms of tissue covering I seem to be able to do the fuselage, rudder and elevator very nicely. I have trouble on the wing, mostly in how i get the top and bottom sheets to meet. its rather messy there. Any tips on wing covering?
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Postby SteveM » Wed Feb 23, 2011 11:14 am

I usually cover the bottom first and make sure the tissue also comes up the leading and trailing edges a bit to ensure overlap. Then I'll cover the top, also allowing the tissue to overlap on the leading and trailing edges. I'll often use a second piece of tissue in the top of the wingtip for best results.

Here is an excellent guide:
http://www.ffscale.co.uk/comp8.htm
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Postby Mustang621 » Wed Feb 23, 2011 11:16 am

ok thanks for the tip, so do you use the extra strip to neaten everything up over the leading and trailing edges?
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Postby SteveM » Wed Feb 23, 2011 11:40 am

No, I just put the top sheet on last so its edges will be trimmed to the bottom of the leading and trailing edges where the seam isn't readily visible.
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Postby Mustang621 » Wed Feb 23, 2011 4:42 pm

ok that makes sense.
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Postby Phugoid » Wed Feb 23, 2011 5:56 pm

I showed some detail of how I cover wings and more on this thread, there's also input by Scigs30 who is a top man WRT covering....

http://balsamodels.com/phpBB/viewtopic. ... 48&start=0
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