Here are some examples of the Soldering and fluxing that I was mentioning above. And on a set of LC smith barrels no less.
Here are the barrels before soldering but with upper and lower rib in place and fluxed. both surfaces to be soldered were cleaned of old solder and degreased. Then flux was applied using a Q-tip being careful to only get it on the surfaces to be soldered. Not on the sides of the ribs or too far onto the outer surfaces of the tubes.
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Here are some photos after soldering is complete. The solder flows into the areas only where flux was applied. Careful application of flux allows for very minimal excess solder to clean up afterwards. And notice... I have to say it... no radiator clamps.
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