Race Car Tubing Fabrication: Part 2

Brazing operations with a torch are seemingly simple. Use the feathered flame and don't overheat the work piece. Once overheated, the brass will not adhere to the base metal. Stop, cool and clean the area, and start over. Many brazed joints look good but are weak because of the overheating. Notice the use of a flux-coated brazing rod here. A different flux must be used on cast iron.

Some torches such as this Craftsman come equipped with check valves. These go a long way toward stopping a flashback in the torch. I highly recommend that your torch be so equipped. A flashback occurs when the tip is blocked and the fire follows the low pressure line, normally theacetylene. If not stopped, the fire will burn up the hose and reach the acetylene bottle. This is not the way to expand your workshop.

These flame arresters attach directly to the regulators. This is a sure-fire way not to have a fire.

For years, arc-welding has been the convenient method of joining metal. The machines can be inexpensive. The welds are usually good in the hands of an experienced welder. The results can be disastrous when an arc-welder is improperly used. This tube was the crossbar behind the seat of a Street Stock. I picked it up off the track after it rolled out of an upside-down car. I suspect in this case the flux filled the weld area and the weld looked good. Always chip the welds.

The E-6011 rod can be used in all positions. The weld is not as nice looking as some others, but it is easy to use and has the ability to stay where it is put. This weld must be chipped, wire-brushed, and then inspected for weld quality.

This tube joint has been burned through with the arc-welder. The amp setting was too high. The fit was poor, thus overheating the edges, allowing the weld heat to burn off metal without joining the parts.

Next month we will be using the Miller MIG welder...

...the Irvan-Smith tube bender...

...and the Speedway Motors tube notcher.