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Building Tips and technical articles. => Building techniques => Topic started by: Motorman on January 27, 2014, 10:36:55 AM
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No, yes, definitely not.
I don't know.
Yes, but it seems like the CL stunt crowd does not.
I hope you found these detailed answers helpful in your quest.
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Is polyspan the same thing as Sig Koverall or is it lighter? I think they are both polyester cloth just wondering about the weight.
Polyspan is more like a paper made from polyester fibers. Sig Koverall is definitely cloth: it's just a simple weave.
Also, is it worth pursuing Polyspan lite because, I've heard it take more dope to fill and comes out just as heavy.
I dunno -- but it may be worthwhile trying something like Esaki tissue over the stuff. Esaki is almost air tight as it comes (it can be hard to get dope to penetrate for adhesion at times, in fact). So it should seal the Polyspan, and provide some complementary strength.
Lastly, can you apply polyspan with Balsa Rite? Should I cut the balsarite 50/50 with thinner like i do for monokote or use full strength?
I don't recall seeing an expert on this forum talk about using anything but dope -- nitrate dope, at that. I suspect that Balsarite would work fine to stick it down, but I don't know if it'd stick it down in a 20-point finish sort of way.
If you try, use the Balsarite that's made to stick down material with no adhesive, not something that's just supposed to help Monocoat along. I have some stuff that was sold as "Polyspan" by Hobby Lobby but which isn't exactly like the "Polyspan" that was sold by CLC (or RCM -- it's been a while). It looks similar, and came with stuff called "Balsa-Loc" that looks & smells like Elmer's white glue, and does a good job as a brush-on, heat-activated adhesive.
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Polyspan will be quite a bit lighter than SIG Koverall. If you want something even stronger than Polyspan, you might look at the local fabric store and check out their "dress liner" material, which is the same sort of polyester mat...looks like heavy silkspan. It'll cost you a couple of ounces, but about bulletproof, and cheap. D>K Steve
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Polyspan doesn't do well around wing tips. Can't pull it tight either, got to rely on just it's shrinking.
I never thought I'd get the hang of using silk, some effort in the beginning, but I managed.
You may want to consider using silk. It's really not difficult at all. JMHO.
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Polyspan doesn't do well around wing tips. Can't pull it tight either, got to rely on just it's shrinking.
I never thought I'd get the hang of using silk, some effort in the beginning, but I managed.
You may want to consider using silk. It's really not difficult at all. JMHO.
Poly span WILL go around wing tips just fine, it is a matter of learning how to use and you also can pull it tight. Like anything else the more you use it the easier it gets to handle.
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This is a very good video that I ran across the other day on polyspan. http://www.youtube.com/watch?v=2oJrkbC3vLc
It will answer some of the questions above.
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As he shows, time and patience. Myself, instead of using X-Acto blades, I use single edge blades. Get them by the box. Also As I don't have sound, don't throw away the scraps. The area he had open up from holding the heat gun in one spot too long can be fixed with a piece of scrap cut in a circle shape. Hard to tear the poly-span. And I have a question about the Stix-It, can it be thinned? My can of the stuff is like molasses.
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...Hey "DOC", He says it can be thinned with lacquer thinner, acetone, or dope thinner.
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I am a big fan of Polyspan, pretty much all I use. I did try the P-span lite one time, did not like it. Took more dope to fill than the regular P-span so I doubt it saved any weight, and pretty sure it is not as strong.
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Mike Haverly says to use a heat gun to stretch the Polyspan as you wrap it around wingtips, etc. He applies it with clear dope...so be careful to keep from setting the clear dope afire. Stretch the polyspan around the tip, turn off the heat gun and set it aside in a safe location, grab the brush and put the dope to it. With the balsa and polyspan both warm, it will dry the dope quickly. But you do have a fire extenguisher in your shop, right? H^^ Steve
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sig coverall is heavier than polly .silk, or silkspan but is way stronger and great for sport or sport stunt ships can be put on with dope and tightend with a heat gun leave a good amount of overlap on the leading edge and don't try to overlap at the trailing edge ,just trim off flush
i fly my Circus King at the ff field i hand launch and land in the grass stubble no holes yet