[TheForge] Re: Cheap Autodarkening Welding Helmet.

[Kenneth Mayer]

>Date: Sat, 09 Aug 2003 19:11:10 -0500
>From: xlch58@swbell.net
>
>I had heard that before.  What I am curious about is how can you tell
>that it is in fact blocking the UV?   I generally don't trust cheap
>tools from Harbor Freight(or elswhere)  and generally inspect and test
>them to the debree that I can on the odd occassion that I buy any these
>days.  So how does one test the UV permeability of a lens?  I can tell


If the front (clear) shield is polycarbonate, it absorbs 99%+ of the UV.
There's an OSHA spec that requires welding lenses to provide UV protection
at all times.  The instruction sheet that came with the helmet probably had
a paragraph that said to use only manufacturer-provided front shields, so as
to maintain the UV protection.

A quick go/no-go test for UV absorption is to look at a UV light source
through the lens/shield.  The light source souuld should appear dark.

>it is stopping the visible spectrum alright, but outside of that is
>there an easy way of verifying?   Regarding the sensitivity of the auto
>feature, it had two switches that adjusted sensitivity (high and low)
>and speed ( fast and slow).   I used it in the high/fast setting as the
>other settings were nothing like my sellstrom that I have gotten used
>to.   On the high sensitivity setting it tends to darken even on
>sunlight reflected off the bare metal, but I would rather that than the
>alternative.


You get what you pay for.  For hobby work, the inexpensive helmets are
perfectly adequate.

Ken
:-)