A TIG back cap is an insulator and:
Back caps typically come in 3 sizes (related to their length):
A new Tungsten electrode is normally about 7″ (175mm) long. As the Tungsten electrode gets shorter, you can change the back cap to a smaller size. A smaller back cap allows the TIG torch to be used where space is restricted. So, keep some shorter Tungsten electrodes back for this purpose, rather than using the electrode up completely.
Table Showing the Different TIG Back Cap Sizes:
|TIG Torch Fittings Compatibility – Back Caps
This is only a guide, please refer to the manufacturers data sheets…
1 Manufacturers may use a different code, sometimes replacing the first two letters with their own combination.
Back cap o-rings prevent the escape of shielding gas from the back of the TIG gun head. More detail on back cap o’rings (such as size and type) can be found in the article ‘TIG O’Rings‘.
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