Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Old May 17th 12, 06:53 PM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Dec 2006
Posts: 635
Default How do welding shade numbers add up? Eclipse viewing.

I want to look at the eclipse this weekend.
Everybody says a #14 welding shade is good.
I don't have one.

So, how do the numbers stack up when you use 2?
I'm guessing it's not linear, so 7+7 doesn't = 14???

What's the math for stacking welding shades?

Thanks, mike

  #2   Report Post  
Old May 17th 12, 09:22 PM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Jul 2009
Posts: 648
Default How do welding shade numbers add up? Eclipse viewing.

mike wrote:
I want to look at the eclipse this weekend.
Everybody says a #14 welding shade is good.
I don't have one.

So, how do the numbers stack up when you use 2?
I'm guessing it's not linear, so 7+7 doesn't = 14???

What's the math for stacking welding shades?

Thanks, mike



A much better idea is to punch a pinhole in the center of one end of a
shoebox , and tape a piece of white paper inside the other end . Point the
pinhole end at the sun , there will be an inverted IIRC image of the sun
on the paper if you've lined it up properly . Similar in principle to a
pinhole camers , you might google "pinhole eclipse viewer" or similar for
more info .
Welding lenses are not really suitable for viewing the sun , though many
people do it ...;
--
Snag
Learning keeps
you young !


  #3   Report Post  
Old May 18th 12, 12:01 AM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Aug 2010
Posts: 934
Default How do welding shade numbers add up? Eclipse viewing.

"mike" wrote in message
...
I want to look at the eclipse this weekend.
Everybody says a #14 welding shade is good.
I don't have one.

So, how do the numbers stack up when you use 2?
I'm guessing it's not linear, so 7+7 doesn't = 14???

What's the math for stacking welding shades?


More than the dark factor, for eclipses, is the UV factor, and window glass
(and plastic) is fairly opaque to UV.
Beer's law would proly indicate that more lenses would be better for UV than
one dark lens, regardless of the net tinting.
http://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law After all the
bull****, Absorption is linear with thickness.... LOL

Of course, Snag's advice is always good.
--
EA



Thanks, mike



  #4   Report Post  
Old May 18th 12, 12:08 AM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Aug 2006
Posts: 1,621
Default How do welding shade numbers add up? Eclipse viewing.

On Thu, 17 May 2012 15:22:39 -0500, Snag wrote:

mike wrote:
I want to look at the eclipse this weekend. Everybody says a #14
welding shade is good. I don't have one.

So, how do the numbers stack up when you use 2? I'm guessing it's not
linear, so 7+7 doesn't = 14???

What's the math for stacking welding shades?

Thanks, mike



A much better idea is to punch a pinhole in the center of one end of a
shoebox , and tape a piece of white paper inside the other end . Point
the pinhole end at the sun , there will be an inverted IIRC image of
the sun on the paper if you've lined it up properly . Similar in
principle to a pinhole camers , you might google "pinhole eclipse
viewer" or similar for more info .
Welding lenses are not really suitable for viewing the sun , though
many
people do it ...;


If you have a room available that's sunny at the time of day of the
eclipse, cover up the windows and make a pinhole in the shade. You get a
lot bigger solar disk to view, and if you want you can make multiple
holes.

Because you need to make a tradeoff between brightness and focus, you
want a bigger "pinhole": if I recall correctly a 1/16" or even 1/8" is
appropriate for a ten foot distance.

I remember one solar eclipse where, after leaving the building where us
engineering staff had converted a conference room into a solar
observatory, I noticed that the little sun-dapples filtering through the
leaves of the trees were all little solar eclipse pictures.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com
  #5   Report Post  
Old May 18th 12, 12:51 AM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Dec 2009
Posts: 619
Default How do welding shade numbers add up? Eclipse viewing.


"Existential Angst" wrote in message
...
"mike" wrote in message ...
I want to look at the eclipse this weekend.
Everybody says a #14 welding shade is good.
I don't have one.

So, how do the numbers stack up when you use 2?
I'm guessing it's not linear, so 7+7 doesn't = 14???

What's the math for stacking welding shades?


More than the dark factor, for eclipses, is the UV factor, and window glass (and
plastic) is fairly opaque to UV.
Beer's law would proly indicate that more lenses would be better for UV than one
dark lens, regardless of the net tinting.
http://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law After all the bull****,
Absorption is linear with thickness.... LOL

Of course, Snag's advice is always good.
--
EA


Arc welding puts out lot's of UV. Why wouldn't a helmet already
have UV filters in it?
Art




  #6   Report Post  
Old May 18th 12, 01:25 AM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Aug 2010
Posts: 934
Default How do welding shade numbers add up? Eclipse viewing.

"Artemus" wrote in message
...

"Existential Angst" wrote in message
...
"mike" wrote in message
...
I want to look at the eclipse this weekend.
Everybody says a #14 welding shade is good.
I don't have one.

So, how do the numbers stack up when you use 2?
I'm guessing it's not linear, so 7+7 doesn't = 14???

What's the math for stacking welding shades?


More than the dark factor, for eclipses, is the UV factor, and window
glass (and plastic) is fairly opaque to UV.
Beer's law would proly indicate that more lenses would be better for UV
than one dark lens, regardless of the net tinting.
http://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law After all the
bull****, Absorption is linear with thickness.... LOL

Of course, Snag's advice is always good.
--
EA


Arc welding puts out lot's of UV. Why wouldn't a helmet already
have UV filters in it?


Even better for eclipses!
--
EA


Art



  #7   Report Post  
Old May 18th 12, 01:55 AM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Jul 2010
Posts: 2,510
Default How do welding shade numbers add up? Eclipse viewing.

On 2012-05-17, Artemus wrote:

"Existential Angst" wrote in message
...
"mike" wrote in message ...
I want to look at the eclipse this weekend.
Everybody says a #14 welding shade is good.
I don't have one.


[ ... ]

Arc welding puts out lot's of UV. Why wouldn't a helmet already
have UV filters in it?


It does -- and the auto-darkening ones block the UV even when
they aren't dark.

But -- I suspect that the problem with viewing the sun is more a
matter of IR than UV -- something which can boil the back of your
eyeball. Gas welding glasses have good IR blocking. Arc welding hoods
have good UV blocking. Probably you want both at the same time for
viewing an eclipse -- if you don't go with the pinhole camera approach,
which strikes me as the best -- especially since you can have more than
one person viewing the image at once, instead of fighting over the
filters. :-)

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
  #8   Report Post  
Old May 18th 12, 02:28 AM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 170
Default How do welding shade numbers add up? Eclipse viewing.

mike used his keyboard to write :
I want to look at the eclipse this weekend.
Everybody says a #14 welding shade is good.
I don't have one.

So, how do the numbers stack up when you use 2?
I'm guessing it's not linear, so 7+7 doesn't = 14???

What's the math for stacking welding shades?

Thanks, mike


Try These for a better view.

http://www.sunguntelescope.com/MAIN.html

http://cdn.transitofvenus.org/docs/B...Sun_Funnel.pdf

--
John G


  #9   Report Post  
Old May 18th 12, 02:29 AM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Oct 2011
Posts: 1,954
Default How do welding shade numbers add up? Eclipse viewing.


"mike" wrote in message
...
I want to look at the eclipse this weekend.
Everybody says a #14 welding shade is good.
I don't have one.

So, how do the numbers stack up when you use 2?
I'm guessing it's not linear, so 7+7 doesn't = 14???

What's the math for stacking welding shades?

Thanks, mike


Sent my wife today for two 4 x 5 shade 14 lenses. They said they were out,
and had sold 14,000 lenses. We are SMACK DAB in the middle of the path here
in Toquerville, Utah. My NexGen only goes up to 13. What's up with that?

Steve


  #10   Report Post  
Old May 18th 12, 02:32 AM posted to rec.crafts.metalworking
external usenet poster
 
First recorded activity by DIYBanter: Jan 2012
Posts: 1,622
Default How do welding shade numbers add up? Eclipse viewing.

Tim Wescott wrote in
:

I remember one solar eclipse where, after leaving the building where us
engineering staff had converted a conference room into a solar
observatory, I noticed that the little sun-dapples filtering through the
leaves of the trees were all little solar eclipse pictures.


I've seen that before. Way cool, isn't it?



Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
OT shot of eclipse for Jeff Gerald Ross[_2_] Woodworking Plans and Photos 7 February 22nd 08 02:55 AM
Need help with Eclipse AVN-2454 Todd Electronics Repair 0 September 18th 07 05:18 AM
Eclipse Scroll Saw Pops Shop Woodworking 0 March 16th 07 04:11 PM
Eclipse! Mary Fisher UK diy 13 March 29th 06 10:15 PM


All times are GMT +1. The time now is 10:50 PM.

Powered by vBulletin® Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright 2004-2017 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"

 

Copyright © 2017