Page 89 - Making things move_ DIY mechanisms for inventors, hobbyists, and artists

70 Making Things Move

commercial parts after a design has been finalized. You can find all kinds of rivets and
rivet tools online at McMaster.

As with other permanent fastening methods, I recommend avoiding rivets unless they
are a last resort, because you will not be able to easily redo and adjust your designs.

Welding, Brazing, and Soldering

Welding, brazing, and soldering are ways of joining metal with metal by using heat.
They are all permanent joints and need to be reheated, cut, or both in order to reverse
them. Welding melts two similar metals together, sometimes using filler rod of a
similar metal. Brazing and soldering both use heat to melt dissimilar metals, as a kind
of glue between two pieces.

Welding
In welding, two metals are joined together by melting them along a seam or at a spot,
sometimes by using a similar metal to fill the voids. The two main types of welding are
gas welding and arc welding. Gas welding uses a blow torch that combines a fuel
(commonly acetylene gas) with oxygen to produce a flame that melts the two pieces
of metal you are welding together. Arc welding uses a DC or AC electrical current that
is converted to heat to melt the materials. There are two common types of arc
welding:

1. Tungsten inert gas (TIG) welding uses a pointy metal electrode to initiate the
arc between it and the materials to be welded. You can also supply a filler
material in this arc as you go along a weld seam, but this method takes
considerable coordination.

2. With metal inert gas (MIG) welding, a wire is fed at a constant rate through
the welding tip while the materials you are welding heat up. This method still
takes practice to master, but is slightly easier to learn than TIG welding.

NOTE If you want to learn more about welding, look for classes at your
local art or community center. For example, in the New York City area, check
out the Educational Alliance (www.edalliance.org) and 3rd Ward
(www.3rdward.com) sites.