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Is the inside surface of clear copper tubing, such as used in refrigeration systems, anodized or have some other finish applied to it? It appears to be impossible to solder to, even using acid flux, unless the surface is thoroughly sanded (or use steel wool or a wire brush). The inside surface "as is" looks clean, with no darkening or oxidation, but is smooth, lacking the tiny scratches of sanding with high grit sandpaper, or using steel wool on it.

The vial contains liquid-metal particles suspended in ethanol. The particles were used to demonstrate heat-free soldering. Credit: Christopher Gannon/Iowa State University =========================================================================================================== Martin Thuo likes to look for new, affordable and clean ways to put science and technology to work in the world. His lab is dedicated to an idea called frugal innovation: "How do you do very high-level science or engineering with very little?" said Thuo, an assistant professor of materials science and engineering at Iowa State University and an associate of the U.S. Department of Energy's Ames Laboratory. "How can you solve a problem with the least amount...

Almost ever electronic device made today except some for the military have solder joints that contain no lead. This is an effort to save our groundwater and our public health. The fact that the lead has been generally replaced with silver or bismuth, both of which are actually greater health risks than lead, well we’ll leave that one for Ralph Nader. The longer-term trend is toward all-tin connections, anyway, but they don’t work very well, either. Costs have gone up for computers with lead-free solder, mean time between failures (MTBF) has gone down (in this case down is bad) and...

Defense Secretary Robert Gates says American soldiers have more than their military might and training on their side in the war in Afghanistan. Some have pink underwear.

A video letter from a solder in Iraq.

The war in Iraq has hit home with a local family's loss of a son. Jesse Givens, son of Dennis Givens of Jefferson City, drowned last week when his tank plunged into a canal in Fallujah, about 30 miles west of Baghdad. Pfc. Jesse Givens Pfc. Jesse Givens, from Joplin, was a soldier in the Heavy Company, 2nd Squadron, 3rd Armored Cavalry Regiment. He was the driver of a 65-ton, four-man tank that fell into the river when the bank underneath it gave way. A story by the Colorado Springs Gazette said Capt. Bren Workman, a spokesman for the regiment,...