RE: UV Eye Protection?

As a disclaimer I should add that the welding curtain provides a good
measure of protection from incidental UV exposure. In other words, if I
or someone else happens to glance in the direction of the curtain, the
curtain blocks and disperses enough of the UV to prevent damage that
might otherwise occur from a prolonged direct exposure. I certainly
would advise against looking through the curtain at the UV source and at
the exposing bed while the machine is operating for any length of time.
Also, I have the plateburner about 20 feet away from any traffic or
other work area. I also avoid looking directly at any reflection coming
from the ceiling.

As indicated by my fogging tests with emulsions, there appears to be
either: 1) some minor amount of UV that still gets through the curtain
or; 2) minor fogging of sensitive materials placed near the machine from
UV reflected from the ceiling; or 3) the curtain may effectively block
most/all the UV but the emulsions were minimally sensitive to the
ambient room illumination (daylight full-spectrum fluorescent tubes
which probably have some UV output). I suspect the minor fogging
occured primarily as a result of reasons #2 & #3, but I can't totally
rule out #1.

A quick search on the internet turned up these UV transmission charts
for a couple different welding curtains:

http://www.goffscurtainwalls.com/images/WeldviewUVResistanceChart.jpg

http://www.traxindprod.com/welding/welding2.html

showing some minor near UV transmission of curtains by other
manufacturer. Note that the colored curtains appear to be a bit more
efficient in blocking near UV. One company also states their curtain
material "is not intended as a substitute for proper eye protection for
direct viewing of welding arcs at close range" and others suggest
consulting them on minimum safe distances for direct exposures. Other
sites had similar warnings about prolonged direct viewing of carbon arcs
through the curtains. So again I think the safest thing is to avoid
looking directly at the UV source and staying some distance away from
the curtain while the machine is operating.

It also appears that prices and sizes vary between manufacturers and
that the vinyl curtains can be cut to size. I ordered a standard size
and color and received it within one week from the local distributor.

According to a colleague who is a welding instructor, having folds or
doubling the thickness of the curtain layers enhances the UV blocking
effect.

Joe

>>> schuyler@bellsouth.net 01/21/05 7:14 PM >>>
Thanks for the suggestion. I picked up a 6x6 Tillman brand
(www.jtillman.com) curtain from a local welding supply today for ~$38.
In
my case, I cut it down the center fold crease (it's vinyl, so it will
cut
with plain scissors) and attached it to an Amergraph plate burner
draping
down from the top. One-half of the curtain covered both sides and the
back,
and the remaining half is attached to the front so it can be flipped up
out
of the way for access to the machine's bed and controls. As a bonus, it
will not only save my eyes, but also keep cats--one began working on his
tan
as soon as the machine was in the house--and dust out of the burner.
The
only drawback I have found is that the curtain smells/feels like it has
a
thin film of motor oil on it from the manufacturing process, and I may
take
it down to give it a good bath and get rid of that.

-Schuyler

-----Original Message-----
From: Joe Smigiel [mailto:jsmigiel@kvcc.edu]
Sent: Thursday, January 20, 2005 9:13 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: UV Eye Protection?

>>> schuyler@bellsouth.net 01/20/05 10:05 PM >>>
>>I was wondering what the more safety conscious of us are wearing for
eye
protection against UV light. I'm finally working with a machine
powerful
enough that I'm concerned about UV exposure, and I want to make sure I'm
doing everything I should to protect my sight. Almost everything
eyewear
today says it blocks 99.9% of UV, but <<

I purchased an ~6'x10' welding curtain from a local welder's supply
house for about $25 IIRC. It hangs from a suspended ceiling via shower
curtain hooks and encircles the NuArc 26-1K plateburner that I use for
alternative processes. I bought it wide enough so that overlaps about
6" in the front of the unit and I close it using a couple of those large
magnetic clips that are meant to hold papers/notes to metal cabinets.
This allows easy access to the front of the machine and controls. There
is also about 3" of space between the curtain and ceiling so that heat
has a chimney-like escape route from the unit.

Using this curtain I don't have to worry about the UV or wearing
personal protection. I've tested some papers coated with cyanotype and
VDB emulsions placed about a foot from the curtain over an exposure of
about 10-15 minutes and very little fogging occurred so I assume the UV
is blocked safely as long as I don't stare through the curtain for any
length of time while the prints are cooking. This setup allows me to be
in the same room while the UV unit is operating without worrying about
burning up my retinas. Also, the curtain is fairly transparent to
visible wavelengths (like a big gray neutral density filter) so I can
actually check the exposure progress on the LED display (and within the
frame if I had any reason to do so, which I don't) while the UV is on.
A similar setup perhaps could isolate your machine safely. Plus, they
come in a variety of colors for the fashion conscious.

Now, if I could only do something about the noise the unit makes I'd be
a happy camper.

Joe
Received on Fri Jan 21 20:17:04 2005