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General control line discussion => Open Forum => Topic started by: sleepy gomez on June 16, 2010, 05:24:35 PM
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Most fuel proof (15% nitro): Dope, epoxy, polyurethane, Elmer's white glue, or any other. I want to experiment with making a non metal tank. Any thoughts?
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Epoxy, Poly-u, dope in that order. Not sure, but I don't think Elmer's white glue is. Never really tried that before.
Paul
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J B WELD TRY THAT
TOM WEEDMAN
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Granite.
Granite (pronounced /ˈɡrænɨt/) is a common and widely occurring type of intrusive, felsic, igneous rock. Granites usually have a medium to coarse grained texture. Occasionally some individual crystals (phenocrysts) are larger than the groundmass in which case the texture is known as porphyritic. A granitic rock with a porphyritic texture is sometimes known as a porphyry. Granites can be pink to gray in color, depending on their chemistry and mineralogy. By definition, granite has a color index (i.e. the percentage of the rock made up of dark minerals) of less than 25%. Outcrops of granite tend to form tors, and rounded massifs. Granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels.
Granite is nearly always massive (lacking internal structures), hard and tough, and therefore it has gained widespread use as a construction stone. The average density of granite is located between 2.65[1] and 2.75 g/cm3, it's compressive strength usually lies above 200 GPa and its viscosity at standard temperature and pressure is ~4.5 • 1019 Pa·s.[2]
The word granite comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a crystalline rock.
Granitoid is used as a descriptive field term for general, light colored, coarse-grained igneous rocks for which a more specific name requires petrographic examination.[3]
All this is assuming, of course, that your airplane might be a little tail heavy. If not, then I'd try any number of commercially available tanks made of tin stock, copper or brass tubing, and a little lead solder to keep things from leaking. The cool part about a granite tank is that after you've crashed a few airplanes, you can always glue 'em together side ny side and end to end to make a small countertop or a small boat anchor. Water based gues are not advised for anchors, btw. Lest you find yourself drifting out to sea, where there are no flying circles.
Hope this helps.
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Most fuel proof (15% nitro): Dope, epoxy, polyurethane, Elmer's white glue, or any other. I want to experiment with making a non metal tank. Any thoughts?
I tried various epoxies. The best was the stuff I got from David Fitz. Here's a link: http://www.nclra.org/WayneTrivin/CompositeTanks.html
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Hi Sleepy,
If longevity is not an issue, I welcome you to try as you will. If on the other hand it is, a light well executed airframe has no need for epoxy based fuel reservoir. I know the Spanish dirt bikes of the 70's used fiberglass construction for their gas tanks but it is sincerely my feeling (as witnessed by the use of JB product to plug overflows on old 1/2 A tank which has disintegrated) that that a well crafted sheet metal tank for our purposes is best, especially if you can't locate the tank far enough one way or the other and need to move the uniflow vent kind of semi inconveniently. The Einstein's of this game would tell you that it (the vent about 7/8 forward of the pickup....my numbers) needs located just above (1/8" up on pickup center...their numbers & mine) as a hedge coming out of the gate on a full fuse ship for equal insides and outsides. Use K&S sheet, copper tubing and solder (60/40 per AR @ R shack) which then needs kicked down the street and re-pressurized while submerged to reveal any potential week spots, then re-soldered per required.
Anything worth doing is worth doing 2 excess and prize winning stunt platforms are typically found using metal fuel reservoirs,
Grady
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... prize winning stunt platforms are typically found using metal fuel reservoirs
Lately, not the big prizes.
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Most fuel proof (15% nitro): Dope, epoxy, polyurethane, Elmer's white glue, or any other. I want to experiment with making a non metal tank. Any thoughts?
Polyester has been mentioned, too ("fiberglass", although you can make polyester-carbon fiber laminates as readily as polyester-glass). But I'd check it against nitro.
Also, just about all the modern resins aren't single things -- they're families; the epoxy, polyester, polyvinyl, polyurethane, etc., resin you find in one factory may have significantly different characteristics (and price) than the 'same' stuff in the factory next door. I'm most familiar with polyester, and there's a huge range from el-cheapo shower-stall resins that'll darn near melt if you paint the part black and leave it in the sun, vs. resins designed for use in nuclear reactors that'll stand up to 400 degrees F and much more corrosive chemicals. The situation is the same with epoxy, or poly-damn-near-anything: there's cheap and there's good.
I wouldn't be surprised if cheap polyester boat resin melted or embrittled from contact with fuel. Even if it did I wouldn't be surprised if good polyester 'technical' resin did just fine. I'd have a bit more faith in cheap epoxy resin, but not much. If you were going to manufacture these in quantity you could get help from the resin supplier's tech support -- you may yet be able to, if you can interest the right guy in answering your questions. It never hurts to call up the hobby glue places (try the folks that sell materials for composite layup) -- you'll get someone who knows what's in fuel and knows the resins, and can at least call the manufacturer's tech support people if you get him interested enough.
Make a test piece with fiberglass reinforcement so it'll be cheap to make and easy to see the resin, then chuck it into a can of fuel for a week -- see what you can see.
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Or you could research the manufacturers' Web sites to find out what is chemically resistant, then get some of that.
Here is another interesting tank concept from a former F2D world champ: http://home.planet.nl/~wakke007/ .