# Thread: How many lux at 1 meter do I need to start fires?

1. ## How many lux at 1 meter do I need to start fires?

How many lux at 1 meter do I need to start fires?

Trying to figure out the math with 50,000 lux from the sun plus a magnifying glass, but I figure some of these people burning stuff with their lights must have an idea of how many lux their hotspot is.

2. ## Re: How many lux at 1 meter do I need to start fires?

Originally Posted by sparkysko
How many lux at 1 meter do I need to start fires?

Trying to figure out the math with 50,000 lux from the sun plus a magnifying glass, but I figure some of these people burning stuff with their lights must have an idea of how many lux their hotspot is.
This depends on the infrared contents in you light source, sun and incan lights has a high infrared contents, led does not have this.

3. ## Re: How many lux at 1 meter do I need to start fires?

Roger, okay, so my question is an invalid one! Oh well.

4. ## Re: How many lux at 1 meter do I need to start fires?

Tomorrow I'll do some homework in the appropriate subforum. But it's quite late and for now there's probably no harm in disclosing my ignorance.

5. ## Re: How many lux at 1 meter do I need to start fires?

Originally Posted by sparkysko
How many lux at 1 meter do I need to start fires?

Trying to figure out the math with 50,000 lux from the sun plus a magnifying glass, but I figure some of these people burning stuff with their lights must have an idea of how many lux their hotspot is.
sounds almost like you want to look in the laser subforum

6. ## Re: How many lux at 1 meter do I need to start fires?

Lux measures the spectrum visible to the human eye. The typical incand torch fire starters work based upon their invisible infrared output. Another reason to include incands in your toy chest, assuming this is a desired, safe, adult activity.

7. ## Re: How many lux at 1 meter do I need to start fires?

Assuming at this point that you're still curious which incan lights would best light fires, bulb lumens will be sufficient for gauging. A mag85 at about 1300 lumens will light one if you're patient. If you want fire in a few seconds the mag623 w/15.6V battery pack is around 4500 lumens and will do nicely. Mine has ignited dry pine needles in 2-3 seconds. Being perfectly honest though, the novelty wears off quickly.

EDIT: Here is some recent discussion with various options mentioned.

8. ## Re: How many lux at 1 meter do I need to start fires?

Originally Posted by Patriot
Being perfectly honest though, the novelty wears off quickly.
+1

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