stunthanger.com
Building Tips and technical articles. => Paint and finishing => Topic started by: Shug Emery on March 21, 2017, 07:37:48 AM
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As I am in the process of finishing a plane.....I have read a few times that not everyone covers their flaps in silkspan though do cover the rest of the plane parts in silkspan.
Is this common?
Any reason not to cover the flaps?
Thanks for any info.
Shug
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I do, but I suspect some are concerned with warps. I've used 1/2oz fiberglass and sometimes carbon fiber.
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Shug- I think stiffness is an important issue for flaps. Silkspan will help there, but shrinking dope does bother me. I recommend the .56-oz fiberglass and epoxy route. You'll get a lot of torque resistance, if you bias the weave to 45 degrees, but care is important in order to avoid a real mess! (carefully roll each piece up so that you can roll it out spanwise over a very thin - squeegied - coating of epoxy to start). If you do this and then follow up with a second coat of epoxy, after the undercoat as set to a tack, sanding later down to the weave, you will avoid the glass floating up - same with silkspan. You can dope over slightly roughened fiberglass. I have found that fiberglass takes so little epoxy to fill it that you can actually come in under the weight of dope/silkspan or epoxy and CF veil. I don't recommend dope applied over woven glass, because it may shrink and warp the flap and also because it keeps shrinking and revealing the weave pattern.
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Silkspan is good, but use nontautening dope. I use torque tube flap LEs, so stiffness is not an issue, but I use carbon tissue on the wood out of peer pressure.
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Silkspan is good, but use nontautening dope. I use torque tube flap LEs, so stiffness is not an issue, but I use carbon tissue on the wood out of peer pressure.
Is butyrate the non-shrinking type?
Appreciato.
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Is butyrate the non-shrinking type?
Yes. In order of achieved rigidity, moncoat, then silkspan & dope, then carbon veil & dope, then some sort of CF or glass + epoxy.
The best way to do it short of Howard's way is probably to vacuum bag CF onto the thing. Start with flaps that have been lightly coated with dope to inhibit the epoxy soaking into the wood and adding weight, then do the deed. Someone out there sells CF sleeves woven on a 45 degree bias (for making tubes) that would be perfect for this, if you wanted to be that detail-oriented.
Howard probably knows why this isn't as good as using CF tubes for the LE.
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Thanks guys. It is just a profile electric. I have doped them and they are straight so far. Think I'll silkspan and dope but do both sides as quickly as possible.
Shug
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Is butyrate the non-shrinking type?
There's tautening butyrate and nontautening butyrate. I got some of each, made by Randolph. Brodak is mostly nontautening.
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Gee, Howard, and here I thought you machined flaps out of unobtainium.
How's JCT manor shaping up?
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How's JCT manor shaping up?
JCT Manor is coming along nicely, Randy. The shop has room for a laser cutter, so I'm picking one up Friday. Marilou brought the suit of armor up from the wine cellar. I don't know whether to keep it in the library or Ebay it.
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I look forward to flying on your pristine circle. ;D
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Suit of armor... Cool!
Would really be something to see someone fly control line in a get up like a suit of armor.
I bet our resident flying clown (Shug) could pull that off!
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Well Howard has also flown in a clown suit so I hear, perhaps he should step up and try with the Suit of Armor as well,, it would be a nice resume filler for the JCT
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There's tautening butyrate and nontautening butyrate. I got some of each, made by Randolph. Brodak is mostly nontautening.
I thought Brodaks was tautening. Wonder if I'm using the wrong stuff?! Does the can of dope specifiy?
Chris
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I thought Brodaks was tautening. Wonder if I'm using the wrong stuff?! Does the can of dope specifiy?
I base that on only one airplane. I covered an All American with silk and used Brodak clear. It was wrinkly and baggy. I called Windy, who recommended putting on some Sig Supercoat, which tightened it up.