[TheForge] Re: Subject: Didymium? I say "no way."

[Chuck Robinson]

Hey Mike,
I have a full face shield that Jim Schell sold me about 10 years ago. It is 
similar to the one in the below link:
http://www.baileypottery.com/safetyequip/eyesafety.htm
The main advantage is, it eliminates the sodium flare, so I can see my 
billet much more clearly and easily detect any welding voids.  Almost like 
having X-Ray vision The gold filters out the IR so effectively that the heat 
is almost completely blocked.
The gold also does this without reducing your  ability to see what you are 
doing when not looking directly into the fire, the way standard green filter 
lenses do.
As has been said before, the main disadvantage is that the gold layer is 
fragile, and the shields are expensive.

Jim Schell was involved in some of the NIOSH studies done on this subject 
about15 years ago He sent me this in an email:
........... My contact at NIOSH
is:  Mr. Gene Moss-NIOSH-MS-R-13, 4676 Columbia Drive, Cincinnati, OH, 45226
phone:  (513) 841-4374.
I do not have any way to address Doug Learn's comments about UV emissions
from gas or coal forges.  However, while at my studio here in Houston, NIOSH
did check for UV and IR emissions from my electric kilns, propane glory
holes and propane/oxygen torch.  Gene Moss can address each of these areas
for you or you can see his report:  HETA 95-0119-2554.  Doug Learn's
comments about genuine didymium being only in glass spectacles is correct.
The polycarbonate spectacles and faceshields I have incorporate a
"didymium-like" material that mimic's the effects of didymium glass.  The
goal of reducing the yellow sodium flare in didymium polycarbonate lenses is
almost the same as in genuine didymium glass.  The polycarbonate lenses are
much lighter, cost less and are less fragile.
JIM SCHELL
-----Original Message-----
From: Chuck Robinson <crobin at datastar.net>
To: Jim SCHELL <jhschell at ix.netcom.com>
Date: Thursday, April 09, 1998 1:59 PM
Subject: Fw: Didymium glasses and UV/IR protection)


Chuck