Santa has spies in my shop!

[oosik]

I have three baby cats in my work shop. 3 months old. In safe keeping until this coming spring. Then they will be big enough to turn loose on my hoard of field mice. They have already dispatched three mice, that I'm aware of. Mice were probably attracted to the big 'ol dish of cat food & the water dish. They are learning well.

Barn cats are a TREMENDOUS asset out here. The only mouse trap that never needs resetting, functions 24/7 and leaves "presents" on your porch.

 

[Green Acres Homestead]

Does anyone worry about their pets looking at the weld in progress and damaging their eyes?

 

[Code54]

I always have my dog out go the shop when I weld just to keep him safe. Too much hot metal on the floor and the arc can't be good for their eyes.

 

[yomax4]

Yes, Sad deal. I had a poor dog watch my welds and he was later walking along rubbing his face in the grass. I caught him and squeezed potato juice in his eyes. Quite a wreslting match but he recovered.

 

[Sodo]

The intensity drops by the mathematical equation 1/(4 x pi x r**2)

For the weldor, an arc at arms length (2 feet) might be 50/(4 x 3.14 x 2 x 2) = "1"
Meaning an arc of "50" results in an intensity number like "1" for 2 feet away.

Keeping everything the same but moving 20 feet away; the same arc called "50" becomes 50/(4 x 3.14 x 20 x 20) = 0.01
An arc of "50" results in an intensity number like "0.01" for 20 feet away.

So to compare 20 feet vs 2 feet; (.01/1= .01)
At 20 feet, the intensity is 1 hundredth of 2 feet.

The problem is when you focus on something, your eye is trying to put the subject image onto a very specific and accurate location of your retina. And it focuses this intensity upon the part of your retina that you NEED badly (for sharp vision), for a relatively long period. This intensity (.01) is tiny, but its then focused on a tiny, very important area of your retina. And because you're keeping it steady on that one super-important location, it's there for "too long". Its a bad deal! Don't __l00k__ at arcs. Don't subject yourself to repeated exposure.

But anyway, main point being animals who may or may not stare..... distance helps a LOT. It seems like you keep them at least 20 feet away and shadow them of possible.

 

[ning]

The intensity drops by the mathematical equation 1/(4 x pi x r**2)

For the weldor, an arc at arms length (2 feet) might be 50/(4 x 3.14 x 2 x 2) = "157"
Meaning an arc of "50" results in an intensity number like "157" for 2 feet away.

Keeping everything the same but moving 20 feet away; the same arc called "50" becomes 50/(4 x 3.14 x 20 x 20) = 0.01
An arc of "50" results in an intensity number like "0.01" for 20 feet away.

So to compare 20 feet vs 2 feet; the intensity has become (.01/157= .00006) At 20 feet, an immeasurably tiny fraction of the intensity of 2 feet away.

The problem is when you focus on something, your eye is trying to put the subject image onto a very specific and accurate location of your retina. And it focuses this intensity upon the part of your retina that you NEED badly (for sharp vision), for a relatively long period. This intensity (.00006) is tiny, but its then focused on a tiny, very important area of your retina. And because you're keeping it steady on that one super-important location, it's there for "too long". Its a bad deal! Don't __l00k__ at arcs. Don't subject yourself to repeated exposure.

But anyway, main point being animals who may or may not stare..... distance helps a LOT.

The intensity itself drops with r^2, because the surface area of a sphere increases with with r^2. The other numbers are constant.

The difference of intensity of a light at 20 feet vs 2 feet is 1/100, because radius has increased by a factor of 10. Pi doesn't matter here, keep it simple and easy.

 

[Sodo]

oops I fixed it
Not sure how that happened but the calculator on my computer requires parenthesis where they are not normally needed, and I wasn't paying attention then you replied too quickly. Agreed eliminating the constants simplifies the comparison significantly, especially a 1:10 comparison (squared = 1:100)

 

[BukitCase]

Sodo, been a while since I picked on ya so here goes (where's that EVIL GRIN emoji when ya really NEED it??!?)

Even simpler - "inverse square law"... gut feel here, AKA no proof: majority of people whose eyes DON'T glaze over/quit reading at the mere MENTION of "the evil MATH MONSTER" will get the distance to intensity relationship of ANY force that radiates 360* with just those three words...

Spoken by the self-annointed "king of verbosity" But where's the fun of NOT pokin' fun?

OK, I feel MUCH better now... Steve

 

[bcp]

Sodo, been a while since I picked on ya so here goes (where's that EVIL GRIN emoji when ya really NEED it??!?)

Even simpler - "inverse square law"... gut feel here, AKA no proof: majority of people whose eyes DON'T glaze over/quit reading at the mere MENTION of "the evil MATH MONSTER" will get the distance to intensity relationship of ANY force that radiates 360* with just those three words...

Spoken by the self-annointed "king of verbosity" But where's the fun of NOT pokin' fun?

OK, I feel MUCH better now... Steve

Bruce

 

[BukitCase]

Nice shirt Bruce

I find when I'm fabbing stuff that Algebra RARELY enters into the process; but I DO use Geometry and Trig fairly often, then I cheat with a few digital angle toys :laughing: ...Steve