Newsgroups: rec.crafts.metalworking
Subject: Re: Eye shielding? (was: Propane torch recommendations
From: John De Armond
Date: Mon, 11 Jan 93 03:29:28 GMT

hank@well.sf.ca.us (Hank Roberts) writes:
 
>With what torches (short of welding torches) is a green eyeshield needed?
 
Depends on what  you're doing.  The FLAME of a combustion (as opposed
to electric arc) torch does not generate harmful light.  The materials
being heated DO.  If you are gas welding steel or other material
that must be heated to incandescence, any color attenuating lens
will work fine.  The rays are not harmful in the sense of having
a large UV content but they are umpleasant to look at and the IR
radiation can dry your eyes and make them sore.  therefore you
want to choose the attenuation necessary to make your vision
comfortable but no more.  If you are brazing or silver-soldering
something using a flux that emits a strong line, frequency-selective
lens are called for.  A cobalt-blue lens, for example, will make the
bright yellow sodium flame of most brazing fluxes and hot glass
practically transparent.
 
John