Hi! I prefer being safe but with a growing
collection of increasingly strong lasers I am lacking on the safety equipment. I have several class four lasers -
the highest safety class there is. Even with safety glasses on,
a steady beam can start fires and scattered light from the laser dot can be
bad for the health of my skin and cameras. I need to build a beam dump to stop
the beam and the reflections. Later in the video, I will test
how well something I build works. Or not... Wear laser safety glasses when handling strong lasers. Be careful with sharp tools and
don't breathe the fumes from a spray can. First off, I'm neither a craftsman nor a handyman
but you don't need to be to build a beam dump. If I can build a useful one - so can you. Stopping a laser beam seems relatively simple. Take a dark brick and put it in the path of the beam. The dark color will absorb a lot of the light and
transfer it to heat, which the brick will handle just fine. This does work well as a beam stop. The brick will not catch on fire
but there's still a lot of scattered light. I would prefer to catch even more of the light. In a beam dump, also known as a beam trap. You can buy one, but even a small
professional model can be 200 dollars. A lot of money for a simple, passive device
that's easy to make yourself. I will build one based on a project
from laserpointerforums.com. Shout-out to the user clansley for the great tips. The beam dump has three main parts: A box section an end piece with a cone diffuser and a front piece with an aperture. Let's start by building the most
detailed part: the diffuser. It needs to handle the heat from being hit by a laser beam. This solid piece of metal sold as a plumb bob
is an easy and inexpensive solution. It has a high melting point and its pointed end lowers retroreflections of the laser light
- making the beam dump more effective. I will mount it to a plastic end cap using a bolt. Unfortunately, the hole in it does not
have a standard M8 coarse thread. Maybe a fine thread M8?
Or not metric at all. Anyway, this stainless bolt
- technically a screw - will do just fine. Time to drill. First, I find the center of the end cap
and mark it with a center punch. Now, I could drill an 8 mm hole fitting
the outer diameter of the M8 bolt. But for the sake of lighttightness I will drill a 6.8 mm
hole fitting the inner diameter of the M8 thread. These drill bits have a nice golden color
because they contain 5% of the element cobalt. This makes them more durable and
heat resistant than ordinary HSS drill bits. Cobalt bits will happily drill through titanium. But this time I only need to go through plastic... Tip: don't deburr holes in plastic with a drill bit. It will chew the hole bigger. And make sure the end cap is held tightly... *Tsk*
*Sigh* For extra strength - and cooling -
I will use some large washers. Make sure you don't overtighten the bolt in the plastic. Just make it flush and tighten it all
with another washer and an M8 nut on the inside. The end cap is now ready to hold the diffuser - like this. Next part is the box section. A meter long beam dump
would be effective but unhandy. Not to mention how hard it would be
to paint all of the inner side black. The almost mirror-like finish on the inside
has a beautiful kaleidoscopic effect. For a beam dump it is however unwanted. I will make mine 15 cm or 6" long.
Handy and adequate. Luckily, aluminium is a relatively soft metal
so it can be cut with the simple tools I've got. After some deburring, this main part is already made. Easy-peasy. The third main part is the front piece. To protect the plastic while I aim the laser at the aperture
I will cover it with a piece of aluminium sheet. With the main parts finished
it is time for the final touches. I need to paint the shiny surfaces. Without paint, the beam dump will
reflect the light - not absorb or trap it. Here demonstrated with a strong, green laser. For a better result, the paint needs
to be black, matte and heat resistant. This paint will handle up to 650°C
and harden at room temperature. Convenient compared to other heat-resistant
paints that will need up to 400°C to harden. I have no experience in painting aluminium
but I prepared it like this. I was in a hurry and painted the in- and outside in one go. For a better looking result you should mask the outside
and paint the inside first at close range. After removing the masking tape you can
paint the outside at the right distance for a spray can. After drying, the parts are ready for the final assembly. The end caps are meant for a wall thickness from 0.8 to 3 mm. Should fit the 2 mm thick walls on this box section,
though it does look like a tight fit. I could try with some percussive persuasion but I feel like a bar clamp will give me more control. That is tight.
It is NOT falling out anytime soon. The beam dump already has the desired 'black hole' effect. Time to add some feet. The square ones may match the overall design the best
but I will go for the round ones. Don't want it to look like something crafted in Minecraft... With the front piece attached
it is ready for test. Will it work as intended? A big, big thanks to all my patrons. You have proven to be the most reliable
support during hard times like 2020. If you want to help me keep going with the videos too
you can sign up on Patreon. For only a dollar a month you get full access to all posts. Link in the description. Thank you. All right, time to test if it works. I will start gently with a sub 50 mW laser. The brick has a strong reflection.
Notice the white part of the dot. That's actually green but very bright, overexposing the camera. Will the beam dump stop this strong reflection? Oh yes, that's better than I expected. I thought there would be some green glow coming out
of the beam dump - but it looks dark from this angle. Way safer than the brick. Here's the same test in a dark room. I hope you can tell how big of a difference it makes. It is even bigger in real life where the brightness
is not limited by the camera and screen. Going up a safety class, I am now
using a 10 times stronger green laser. Wauv. That's good. This time I am seeing some green glow from the inside
but nothing is bright enough to overexpose the camera. Now for a class four laser. A 700 milliwatts red with a multimode diode. The beam quality sucks with a
wide beam and a lot of spillage. The beam dump however still makes a big difference. Understated by the camera and your screen. As a final test, I will use my strongest, single-diode laser. A 1500 milliwatts blue laser. I think it is fair to call this a success. Finally, I have a proper beam trap. A long due, major upgrade to my laser safety equipment. And it was an easy build. Now, it's your turn. My original plan was to make several
front pieces with different aperture sizes. A 10 mm aperture is simply too small at a larger
distance between the laser and beam dump. In stead of interchangeable front pieces
I will experiment with a single, variable aperture. Should be more practical - if it works. The slow boat from China just hasn't arrived yet. Subscribe for an update video. And remember to click like, if you liked this video. If you want to see more laser tests I recommend the video where I test
the power and wavelength of my strongest lasers. Links in all the usual places. Thanks for watching and a Happy New Year!
