Although flare connections are very reliable, people don’t use ’em as often as they could because creating them requires special equipment. Fortunately, you really don’t have to make a huge investment in tools — General Tools manufactures an inexpensive flaring tool to get you started making solid flare connections. Their flaring tool makes smooth 45° flares in soft copper, aluminum, brass, and other common, thin-walled tubing.
The hardened and plated steel bars of the flaring tool come with seven hole sizes marked: 3/16”, 1/4”, 5/16”, 3/8”, 7/16”, 1/2”, and 5/8”. Loosening the wing nuts allows the bars to spread for inserting and removing tubing. Twisting the sliding T-handle on the heavy-duty screw drives the freewheeling 45° plated cone into the tubing, flaring it to match the profile of the hole in the bars. Why is one bar much longer than it needs to be? It’s designed for mounting in a vice.
Expect to pay around $20 for General Tools’ standard flaring tool.