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FrozenGate by Avery

Brick beamstop effectiveness?

Bricks are fine but a little big, I have a simple cube of aluminum painted black
with plain old flat black spray paint and it works just fine for me, I keep it next
to the OPHIR head of my LPM and when I'm getting ready to measure a laser
diode with a lens in front of it I always point the laser at the block first to be
sure it is not set to a pin point and if it is I un-focus it or spread the beam
out to at least 1/4" wide before pointing it at the OPHIR sensor.

Just a simple cube of Al painted black


Ready to meter a laser
 





Well, black-anodized heatsinks sometimes have their problems as well.

Surely they are black, but some of them can be a bit shiney as well, and still reflect a decent amount of incoming light if it is at the right/wrong angle.

Given that, a brick is not that bad an idea, but don't go spraypaint one as that will have some gloss to it as well. You can find bricks that are matte black throughout, which would probably make very good beamstops even at very high power levels.
 
Not much. If you look at a real purpose built beam dump, it's angled inside and made of aluminum or
maybe copper to get the heat away from the surface. Higher power ones are even water cooled. The
matte black coating is a closely guarded trade secret. The only thing I can think of is to go over it with an
acetylene flame to coat it with a thin layer of black carbon soot, but it comes off easily. Recoats just as
easily, though
 
You can build all kinds of contraptions yourself too.

Starting with the concept of a brick, there are several options. You could, for exampe, build a block from several bricks that has a hollow cavity on the inside. Using black bricks or coat them black prior to assembly.

Now drill a hole from the outside into the interor space, and you'll have a far lower chance of any reflections, provided you're pointing the laser into the hole and not next to it etc.

And yes, the art of making something really, really black are somewhat secretive. This stems from military applications, and at times even universities are asked not to publish such properties when they are not key to the research.
 
That certainly is a creative solution, and would be fine for low powered lasers.

I have my doubts how well it would work for modern day several-watt lasers though - i suspect they might be able to melt their way through the plastic at some point.

The advantage of brick and such is that you cannot burn a hole through them easily, at least not until you are shooting beams that are tens or hundreds of watts in power.
 
Benm said:
The advantage of brick and such is that you cannot burn a hole through them easily, at least not until you are shooting beams that are tens or hundreds of watts in power.
Click to expand...

Hey man My lightsaber reality edition is in the works! lol
 
I have a 3.5 watt 445nm laser that does not even make it smoke! The key is the 10 coats of tremclad high heat flat black paint. Let each coat dry several hours before recoat. On the fifth coat get a 400 sandpaper or some extra fine steel wool and give it a quick buff to aid in the bonding and to also keep all the paint really level. DO this one more time before your final coat.Dont sand the paint off ,just lightly buff it to even out the finish. Be sure to put lots of paint in the opening!!! If you don't have steel wool or sandpaper, a paper bag works awesome too!
 
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