[Osirus264]

Hi! I'm a newbie in this screen printing game, but I've just recently bought a flood light LED 120W for my exposure on my photo emulsion silk screen. Will it work?

 

[KikRox]

That'll probably isn't strong enough you should try the minimum of the 500 watt. Give that a whirl and see what happens but generally that should be enough to burn your screen. Good luck let me know.

 

[PatWibble]

Is it a UV lED or a regular one?
A regular one won't do anything.
A 120w UV LED will do a reasonable job if it is a 395nm one (they tend to come in two readily available wavelengths of 365nm and 395nm - anything else is a specialist product). If you can find one at 405nm it would probably be better.

It won't be super fast because you will need a relatively large focal distance (height above the screen) to get a good exposure.

 

[TABOB]

LED floodlights will not work well. They will still work... but painfully slow maybe 30 minutes exposure, or something crazy like that.
This is because they emit very little UV light.

For regular emulsion, the common 395nm UV lights will be good enough.
The indicated 395nm is just the peak. They actually emit plenty of 375 to 405nm wavelength.
More watts = more light = faster exposure.
It has to be actual consumption watts though, and not "equivalent".