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Solder or Epoxy?

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Old 02-22-2003, 02:56 AM
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iflircaircraft
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Default Solder or Epoxy?

Hi:
I am building a Super Skybolt (60 size Biplane).
The plans call for wrapping the cabane struts to each other with thin wire then soldering the joint. I've cleaned the cabane wires as directed and used flux.
I can't seem to get a good solder flow and it won't hold worth a damn.
I'm using silver solder and heating with a propane torch.
I was told silver solder will hold anything, but the instructions say to use acid core solder. Am I using the wrong stuff?
Would it be just a strong to wrap the joints with some thread and epoxy the joints?

Tom







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Old 02-22-2003, 10:26 AM
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daveopam
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Default Solder or Epoxy?

The epoxy wont hold. Make sure the heat from the metal is melting the solder and not the flame. JB Weld
would be better than epoxy but solder is the best. later daveo
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Old 02-22-2003, 12:46 PM
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iflircaircraft
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Default Solder or Epoxy?

Yes Daveo:
I'm heating the solder with the wire vs heating the solder with the flame.
Unfortunately, the solder runs off the wires. I've ruined a perfectly new 14oz fuel tank which was under the cabane wires. ERRRGH
My question remains, is silver solder not compatible and thus I should use acid core solder?
This bipe is driving me nuts!!!

Tom
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Old 02-22-2003, 03:25 PM
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Default Solder or Epoxy?

Go to Radio Shack. Get the silver solder they have in a syringe-like applicator. This is a paste of ground solder metal in flux that's about the consistency of Vaseline.

Re-clean the joint area (means unwrapping the wire...) Use 800 grit emery cloth on the music wire and make it SHINE BRIGHT!. Make CERTAIN that the wire you wrapped with is NOT insulated stuff... Coil winding wire has a "shelac" insulation on it... and that makes getting a good joint impossible. Re-wrap. Apply the silver solder after heating the wire structure. It will wick in GREAT. Best stuff I've found for doing the soldered wire landing gear and cabane struts.

somewhere along the line... you goofed up the cleaning process or have bad flux or not enough heat.
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Old 02-22-2003, 04:55 PM
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Default Solder or Epoxy?

... or too much heat (which in some cases may fry the flux before you can make a joint).

That Radio Shark stuff sounds good. I hope they still have it. I think I'll give it a try, too... Thanks FHH!


BTW others, even soft solder will do you way better than epoxy in this appllication -- but do be sure to wrap the joint and although it's not as fussy, cleanliness still counts. All in all, though, silver solder is the way to go if you can. If it really won't behave for you, you may want to try getting together with a flying buddy or someone and see if they do anything different than how you're doing it.
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Old 02-22-2003, 07:03 PM
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Default Solder or Epoxy?

Thanks all......I think I'll try Radio Shack's solder FHH has mentioned

I've re-cleaned the struts......re wrapped them and fluxed them and bought acid core solder as suggested by the instruction book.
The problem is....the solder doesn't wick.....it just sits there and then runs off the wires.

Can I use heavy gauge electrical wire once I strip it of it's insulation to wrap the cabane wires?

The wire wrap they gave me with the kit is ruined!!

I'm spending way too much time with this step than necessary.
If only I paid attention to the teach in metal class in high school.........30 yrs ago........LOL

Tom



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Old 02-22-2003, 07:55 PM
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Default Solder or Epoxy?

Clean off everything again before using the Radio Shack silver solder... its got its own flux and you don't want to mix fluxes. (results unpredictable if they aren't the same type flux...)

You CAN use copper wire... however you might be better off getting thin brass rod from the hobby shop Brass is stronger than copper and has always done better, for me, at doing the LG wrapping than the copper.

The typical reason the sloder runs off the wire is there is something on the wire preventing the solder from adhering.(Oil, grease... insulation coating.) There may be a skin oil problem even... some people's skin oil interferes with soldering (I can't handle wire for wrapping for a week after eating fried chicken...) and if that's the case, you need to avoid touching the wire. Use locking pliers or forceps to handle the wire while wrapping.
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Old 02-22-2003, 09:16 PM
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Default Solder or Epoxy?

Tom, what type of silver solder are you using. There are many different types, the ones marketed by the hobby industries ie. Stay Brite aren't really a silver solder. They only have either a 2% or 5% silver content- about the same as Radio Shack brand. Real silver solders, 45% silver content and greater, really require acetylene torch setups because the melting points on high silver content silver solders is usually greater than 1200 degress.
The Stay Brite types when used with copper wire wrapping will provide an adequate joint for all your solder needs on a 60 size aircraft. Only when you go to larger heavier aircraft will you need a higher silver content solder.
Now, there is only three things that will cause the solder to just set there.
First the parts are not clean (all the parts). Use 120 grit to clean all surfaces, really get them clean, clean the copper wire with 120 grit sandpaper. Every thing must be clean!!!
Second, you're not using enogh flux. If your using the Stay Brite types, it has a liquid acid flux, make sure that all parts are generously coated.
Third, you're not appling enough heat. The trick is to apply heat quickly and evenly to the joint using a propane torch before all the flux evaporates. Then apply solder to the heated copper wrapped joint and watch the solder flow to a beautiful joint.
After soldering with an acid type flux, you need to clean the parts with a water and baking soda solutions to neautralize the acid.
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Old 02-23-2003, 12:24 PM
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Default Solder or Epoxy?

I think your problem may be the propane torch. If your putting the flame directly on the joint to be soldered, chances are your burning off all the flux before you ever put the solder to the joint. I think you would get much better results using an iron. Place the iron on the bottom side of the joint and the solder on the top of the joint, as the solder melts it will wick through and give you a nice strong joint. Also use the smallest diamiter solder you can get, (Radio Shack has some real thin stuff) it will melt much faster than the big think stuff so you'll get solder into your joint before all the flux is gone.
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Old 02-23-2003, 10:19 PM
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iflircaircraft
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Default Solder or Epoxy?

It must have been my skin oils as FHH had suggested.
I did everything as I did before except I wore vinyl gloves while handling everything.
It really worked and wicked very well for a strong joint.
Thanks all for your input and much needed advice.
I used brass wire to wrap the joints and acid solder.


Tom
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Old 02-24-2003, 09:56 PM
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Default Solder or Epoxy?

I have tried several different ways to solder-and I also still get a weak joint-bought a wire feed welder-which is very small wire gauge and has no gas bottle-the flux is in the wire-since the flux is only to remove the air around what you are tacking-but it works very well-I do not have joints breaking loose any longer or countless hours of trying to produce several small assemblies-any pitting I get -I use jb weld as almost a bondo and sand smooth and finish-looks nice and holds-thanks
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