Eye protection and melting furnaces

Jewelry Discussion
1

I know that when one is melting metal with a torch that one needs to
use lenses to protect the eyes from harmful rays. But what if one is
melting metal (silver or gold) in a graphite crucible in a melting
furnace? Is there any need for such lenses in this case? As none of
the books I have make any fuss about this issue I would guess that it
is safe to look into the glowing red crucible to see if the metal is
molten and to check for undesirable sludge floating on the top. Your
feedback will be much appreciated (as I have just acquired a small
electric melting furnace).

Stan

2 
    I know that when one is melting metal with a torch that one
needs to use lenses to protect the eyes from harmful rays.

Idunno. I’ve been working on the bench for over 30 years and have
never worn any eye special eye protection. I do wear glasses which
cut down on ultraviolet and function as a barrier of sorts, but that
was after about ten years on the bench. I do recommend safety
glasses. I can’t imagine that one would “need” special eye protection
for a furnace such as a Handy Melt.

3

Stan, One is ill advised to look at a glowing mass of over 900 B0C,
which emits much infrared light, from close distance and for more
than a brief period. But a quick look for inspection, as you suggest
in your query, is unlikely to do any harm, even in the long run. In
the old days some people working without eye protection as glass
blowers, or were involved in smelting metals in large, open
furnaces, would develop premature cataract. This is nowadays
attributed mainly to infrared light heating the back side of the
lens and the blood vessels in its vicinity. There is more
about hazards to the eye e.g. at
www.potterymaking.org/safetyeyes.html, and if you are interested in
a more fundamental medical treatise go to
www.optometry.co.uk/articles/19990521/Voke.pdf). Good luck, Philip
Quanjer @Philip_Quanjer1

4

YES, absolutely you need protection if you are looking at the molten
metal directly. If you can feel heat on your face, that same
radiation is going directly into your eyes.

I recommend a welders shade #2 at a minimum (my product AUR-99 shade
2.0 or equivalent). This filter blocks all the IR (infrared) energy,
and still allows about 40% visible light transmission. Overall, it is
the best tradeoff between IR filtration and visible light
transmission.

Mike Aurelius President Aura Lens Products, Inc.
http://www.auralens.com mailto:mike@auralens.com

5

Continue from:

  YES, absolutely you need protection if you are looking at the
molten metal directly. If you can feel heat on your face, that same
radiation is going directly into your eyes. I recommend a welders
shade #2 at a minimum (my product AUR-99 shade 2.0 or equivalent).
This filter blocks all the IR (infrared) energy, and still allows
about 40% visible light transmission. Overall, it is the best
tradeoff between IR filtration and visible light transmission. Mike
Aurelius President Aura Lens Products, Inc. http://www.auralens.com
mike@auralens.com

Mike, What lens would you recommend for beginning classes, safety
and flame protection. Students will hard solder copper, brass,
bronze, and silver. Sometimes they will pour ingots of silver or
bronze.

Regards,
James

6

this thread is great and full of info. i wear eyeglasses or contacts
at all times and read in the archives that, “Most glasses and
polycarbonates will stop the ultraviolet. So will most contact
lenses.”

does this mean that i’m okay without further eye protection or do i
need to protect from infrared when soldering with an oxy/acetylene
torch setup?

thanks!!
jocelyn

Jocelyn Broyles
Designer/President
www.jocelynbroyles.com
Costa Rica ph(011 506) 376.6417
U.S. fax (253) 669.1679