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General control line discussion => Open Forum => Topic started by: Dan Berry on October 23, 2012, 07:54:39 AM
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I am getting close to the finish line on the profile Oriental.
I am thinking of using 3M DP-460 epoxy to attach brass tank mounting brackets to a metal tank. This in lieu of soldering them.
I do not have a heavy soldering iron available and I'm not certain that my pencil iron is up to the task.
Will the epoxy hold up to vibration?
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Hi Dan
I've seen people doing it but with J&B Weld, but never did it myself.
The J&B seems to work fine.
Marcus
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Good clean surfaces and the epoxy or J-B Weld will work.
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I'd guess J-B weld first, not sure about the epoxy. OR,
Silicone sealer across the whole back of the tank to a slotted piece of ply. I've done that before with good success.
H^^
W.
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My favorite method for profiles is:
Cut a thin piece of plywood, fiberglass sheet, or carbon sheet slightly larger than the fuselage side of the tank, with enough material at the ends for your mounting bolt slots (for up/down adjustments). Fuel proof it (if it's plywood) with a coat of epoxy. Rough up the back of the tank and adjoining area on mount, then use RTV silicone to attach the tank to the mount and let it dry for at least 24-48 hours. Mount up and fly. This has the advantage of being about as light as soldered metal tabs, but having more surface area and providing some vibration isolation. I've never had one fail. 8)
Whoops...Ward posted while I was typing LOL
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Radio Shack (and others I'm sure) sell a small butane fueled, pencil shaped soldering iron that also has a small torch attachment. I have used this successfully for soldering these types of tabs. I found it much easier to evenly distribute the heat with the small torch than with even a large iron.
Bruce
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I don't believe in tank brackets. I use rubber bands and coat hangar wire.
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I'm deeply suspicious of epoxy, even though I've seen it do wondrous things. I don't think I'd try anything less than JB Weld.
Sheet metal like that doesn't have much thermal mass, and tin plate is about the easiest stuff in the world to solder to. I like using a honkin' big iron myself, but I've heard good things about pencil irons from smart people. So I wouldn't discard the idea of using a pencil iron until I'd tried it.
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Not to highjack the thread, but Phil, what kind of sound comes from your modified muffler ? and does it really cut down a lot of noise ? Thx.
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Radio Shack (and others I'm sure) sell a small butane fueled, pencil shaped soldering iron that also has a small torch attachment. I have used this successfully for soldering these types of tabs. I found it much easier to evenly distribute the heat with the small torch than with even a large iron.
Bruce
You could even use the torch to fix your J-3 fuel tank! Or maybe not... Hey Bruce, I woulda paid you $35.00 for your C-170 - no questions asked!! (As long as you delivered it, of course.)
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The problem with anything other than adjustable side tabs is that you are not able to move the tank to get the fuel flow the same up/inverted. Two 2" side pieces with 4 slots (2 on ea) and JB glued to the flat site of the tank after cleaning and ruffing up the surfaces, will hold the tank forever.
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The problem with anything other than adjustable side tabs is that you are not able to move the tank to get the fuel flow the same up/inverted. Two 2" side pieces with 4 slots (2 on ea) and JB glued to the flat site of the tank after cleaning and ruffing up the surfaces, will hold the tank forever.
Hooks and rubber bands give you adjustability if you space the hooks wider than the tank, and use shims.
Something with slots is prettier, IMHO.
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Thanks for the input. If JB Weld would hold it, I've no doubt that the DP460 will also do it.
Rubber bands aren't an option.
I do find that I need to put the brackets top and bottom--there is no room for them front and back.
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Not to highjack the thread, but Phil, what kind of sound comes from your modified muffler ? and does it really cut down a lot of noise ? Thx.
It depends on the number of baffles used. I had one that you could hear the prop noise over the exhaust.
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You should be able to solder tank mounts with a 40W iron if the tip isn't micro-sized. Let it get hot, then pre-tin both the mounting tab and the tank area. Then locate the parts. I use a stainless pan head screw thru the mounting slot into a piece of wood so I'm not fumbling around with loose parts. Then you can improvise something to press the tank up against it. (Thumb, rubber band, magnet, wood clamp, etc.) If I am making a tank to fit a screw pattern already on the plane, I just layout the same pattern on the soldering board, predrill some pilot holes, and jig everything up. Guarentees that it will fit and not be crooked when I am done. To get better heat transfer from the tip to the parts, heavily tin the tip of the iron. If everything is clean, it usually goes together no problems. One other thing to check is that the tip is free of scale and rust and firmly attached to the iron. A poor connection here will make even a big iron wimpy.
Epoxy is great stuff, but a good solder joint is probably easier to achieve than a good bond joint. I suspect it is also more tolerant of flex-induced failures--but I have no data on that. On the other hand, how many metal tanks can you buy that are glued together?
Dave "McSlow"
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I tried mating a piece of aluminum with slots using JB Weld, to a tank made with K&S .008" tin stock. It stuck to the aluminum fine, but not the tin tank. I ended up soldering slotted brass angle brackets top and bottom. That has worked very well. I just us a Weller soldering gun to do all my tank soldering, along with 2% silver solder from Radio Shack. It is .022 wire with rosin core. Makes beautiful solder joints.
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I've used rubber bands and wire hooks run through fuse holes above and bellow the tank. 4 holes, 2 back, 2 front. Two wires bent so they loop across the back. I use spacers to locate the tank accurately, moving tank up and down as needed to even out engine run, upright and inverted. Staples sell packs of 6inch color rubber bands. On the Magician in the picture I ran 4 1/8 inch bolts through the fuse, mounted wire hooks for the bands to that. I thought it looked neater than the the looped wire. I've seen soldered tabs become undone in flight. A few times as a matter of fact. I think rubber bands are cool when in color. Others no doubt think it crude.
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I have holes through the fuselage as if using wire and then I feed ty-wraps through and around the tank. Make the holes wider apart than the tank and then the tank can be wedged up or down as needed. I got away from rubber bands. After they age they need to be replaced. The plastic ty-wraps are cheap, come in many colors and seeming last forever.
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I used ty-wraps for a while. They last and last. But I had trouble getting them tight enough, also, when adjusting tank height, moving the tank up and down, changed the tension. Hard to get the ty-wrap right when adjusting tank height. At least to my satisfaction. But that's me. Yep. The bands go bad and rot. I always keep some in my field box, stowed in a zip lock. Periodically I inspect and replace. Sometimes I overlook one. They break, curl up, look like a dead worm. Ugly.