[knarf]

Would the dark lens of a welder’s hood be safe enough .. just to locate the sun in the lens of the camera?

[pallis]

A welder’s hood yes, but not goggles for the torch. Try to use a number 10 lens.

[Ratman83]

I heard that it has to be a #14 shade, anything wlse would allow damage to the eye.

[LibWhacker]

From Perkins Observatory:

(METHOD 3) Welder's Glass

Welding glass is used to protect welders from eye damage. The potential damage does not come from hot sparks hitting the eye (although that is a possibility). Rather, the glass prevents the light from the very hot arc from burning an image of itself permanently onto the back of the eye.

Be careful that you use the right kind of glass! Welder's glass is numbered from 1 to 14 with 14 being the darkest. It is only number 14 glass that is dark enough for solar viewing! And NO STACKING! A pair of number 7's or a 10 and a 4 together DO NOT have the same protection as a single piece of number 14 (see unsafe methods for more details).

But to tell you the truth, this method makes me a little nervous. Do we know with certainty that the company that made the glass is reputable, or that there are no defects in the glass? Are we willing to bet our eyesight on it? Personally, I prefer to project the image onto a piece of cardboard or watch the transit online.