Sharks with Frikk'n Lasers - or a nostalgic CO2 laser build

[ThunderSqueak]

===============

I decided to move this to a small website, if you are interested take a look over at

http://home.gci.net/~thundersqueak/CO2_Laser.html

also removed image links from this forum for this project, you can see them in a better fashion on the website. 

Thanks
~Thundersqueak



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So, after chatting with others while watching the makerbot being assembled, nostalgia got me.  I built one of these years ago for a science fair project with my father, well I dont have that one anymore... so here is the start of another!

My new CO2 laser build

So far I have the cooling water jacket built  and sealed.. The clear tubing in the middle is made from a peice of an old aquarium vacuum.  The rest is standard pcv that was glued with pvc glue then later sealed again with JB weld.  I am just using what I have on hand for this, the goal... buy as little as possible   The hose clamps are just applying some pressure while the JB weld sets.  I needed the window so I could see how the plasma in the tube was behaving during operation.  The grey stands are from the hardware store found in the electrical conduit department.

Next to construct are the mirror mounts.  I am going to use a standard sharkbite T pipe fitting, 2 washers, 4 bolts, and a couple grommets to act as a seal and allow angle adjustments.  The mirror will be held on with a nylon washer that is bolted to the adjustment washer.  All surfaces will be sealed with a gasket where needed.   I will show pictures of this later

The power supply that I have on hand is an adjustable 12kV at 30mA, the gas will be a CO2, N2,He mix.

Anyway... enough for 1 night,  Just thought I would show off progress so far on my latest boredom project  

Now... where did I put those dang laser safety glasses.  I think I will need to order a new pair  

[Psi]

Cool.  What wavelength are you aiming for?

[ThunderSqueak]

10600nm

contemplating if I should use commercial mirrors or sputter my own and use a piece of rock salt as the lens.  For an example of a "salt window" laser see



I think I will most likely use a gold plated HR with a ZnSe OC, but that is the fun of this, I can experement.

[slateraptor]

LMFAO!! That shark pic is awesome. Sweet project too; glad to see it coming along.

[ThunderSqueak]

Yeah, been considering what color to paint it, or if I should just leave it white.  I do plan on incorporating that shark logo into it tho

[ThunderSqueak]

Hmm just made a label for it... well a possible label anyway :>

[mikeselectricstuff]

[LukeW]

Cool.  What wavelength are you aiming for?

It will be standard 10.6 micron. You don't really get much choice.

contemplating if I should use commercial mirrors or sputter my own and use a piece of rock salt as the lens.

How fast does a NaCl window degrade or fail due to atmospheric moisture exposure?

One of the reasons ZnSe is a good all-round material is that it's not hygroscopic. Also, maybe you might want to try Germanium for the OC, along with NaCl or standard ZnSe, if you want to experiment with different materials.

Let us know how well you get on with sputtering the mirrors, I'm curious.
You're going to use gold, right? On what substrate material?

[ThunderSqueak]

For sputtering, was probably going to try copper first.  If I buy  a commercially made lense I will get a gold one.   Right now it is on hold for a few until a few other work projects are completed, which should be by the end of the month.   what pays the bills > hobby

If I do make mirrors I plan on filming each attempt, I expect the salt window would last quite a while as Alaska is classified as a desert.  Without a humidifier in my home, the humidity drops to 20% or lower.  I have to actually top off my aquarium regularly as it loses inches of water... always wondered if the fish know this and that is why they always seem to be watching the water level 

Anyway, this is a fun project    Nothing more.

[ThunderSqueak]

Well today I decided to make the mirror mounts, sort of made it up while I went, the materials were 2 large washers, 2 small washers, 6 screws, 6 nuts, 2 sharkbite fittings and a grommet that was used to form the seal and also act as a spring to allow adjustment.

The initial fitting test, at first I was not going to use the larger washer, then as I looked at ways of creating the adjustment it became clear that I simply needed more room to work.  I did have to cut off the first barb of the sharkbite and then file out the center of the washer for a very snug fit.  I used the next ring on the sharkbite to line up the washer at a 90 degree.


The next step was to file down the other side of the sharkbite so that it slid into the glass tubing easily but still be snug, I used a hand file for this, which went quick as brass is a very soft material.

Next, I measured out and drilled the holes for the adjustment screws in some larger washers.  The smaller washer was a bit tight so I later notched that to fit around the adjustment screw heads.

This is the first major dry fitting of it all, The next step was to use some solder paste I had sitting around and then my torch and make all the seals airtight. 


And with the grommet in place, I tested to make sure the seals were airtight by simply hooking up a pump, sealing the couple holes that were open (the end where the lens goes and the gas intake/exhaust and placing the whole thing under water.  There were no bubbles, which is exactly what I need for this project    I know the soldering looks a bit messy but I am doing this with hand tools and only had a small butane torch at hand.  Most of the fun in this is seeing what I can get away with for construction methods and equipment.  I have access to a machine shop and several labs, but what fun is that

Now to figure out how I want to attach the actual mirrors to them, I could simply use a gasket and let air pressure do the work, I may simply design a clip using spring steel and a nylon washer to clip over the lens while waiting for air pressure to kick in.   

and now to start that MITx class... ^^

[slateraptor]

OMG did you really etch a shark on the T fitting??

[ThunderSqueak]

LOL, nope, they actually came that way... but I figured I would leave it... as it is fitting

ok, bad puns aside ... the current issue is the lens mounting mechanism, I am considering just using a gasket and atmospheric pressure, this would probably let me try the widest variety of lenses (dont have to make the lens fit a certain form factor).  Another option I have considered is just using an external spring steel or piano wire clip with a nylon washer making the actual contact to the lens.

I have also considered simply making a bolt on method, which wouldnt be too difficult, soldering a couple bolts on backwards, cutting out a face plate from nylon washer and simply bolting it on.   

Next up, the power supply for this.

[ThunderSqueak]

Ok well I added a mounting system for the mirrors, it is simply 2 screws soldered to the face of the adjustable washer, and I made the bracket that holds it on out of an old optical disk, if I need to use a higher temp material, it shouldnt be difficult at all.  I just wanted to allow it to hold the optics in place until air pressure kicked in, yet be a soft enough material that it would not scratch the delicate optics.


And the first dry fitting of the laser tube,  The epoxy is now curing for all joints that need to be sealed, later I will go over them again with another coat to be sure all seals are solid. 

The optics on order, are a gold HR mirror designed for this purpose and a ZnSe OC lens,  also on order are the proper safety glasses.   I also picked up another free working 15Kv neon power supply.

Looking at enclosures for the control system for this build, figured I might be a little creative and do all the switches and dials with a steampunk feel ( examples http://www.oddee.com/item_96830.aspx ) .... just for fun.  Def needs a HUGE red lightbulb "laser is armed" light on it.   

[baljemmett]

Looking at enclosures for the control system for this build, figured I might be a little creative and do all the switches and dials with a steampunk feel ( examples http://www.oddee.com/item_96830.aspx ) .... just for fun.  Def needs a HUGE red lightbulb "laser is armed" light on it.

Don't forget a couple of decent-sized dials with wildly-swinging needles!  If you want to be pedestrian you could have some that actually indicate some parameter of the system, but where's the fun in that? 

[ThunderSqueak]

Well, this will probably be the last post I do on this, decided to just do a small howto website for it as I go along.

http://home.gci.net/~thundersqueak/CO2_Laser.html 

If you are interested, attached is a pic of the progress as of this moment.  Waiting on the optics and now constructing the power supply setup and control panel.  For the vacuum pump I am going to convert a cheap air compressor, this is within my scope of trying to use only items I can get at the local hardware store using tools also from same type of store.

[slateraptor]

Great stuff!! Looking forward to the rest of your build.

[slateraptor]

How's your laaaaaazzzzeeeeeerrrrrrrrrr build coming along? You should really consider dating the posts on your website.

[sonicj]

would finer thread pitch hardware make alignment easier?

have you ever tried brazing?
-sj

[ThunderSqueak]

It is coming along, I had a few setbacks and a meltdown today with it.  I was fixing a leak in the system and fired it up without the cooling system active, the result was a cracked tube.  There was water in the cooling jacket, but it only covered half the tube.  The tube has been replaced, the epoxy is now curing for another go.    For the few moments it was on today, it did create a beam, which hit a block of wood I had sitting in front of it   So, I know it works.  The gas I used was a mix of nitrogen, co2, and helium.

This is the third tube that I have replaced.  The others were due to either too much tension on the optics or flaws in the glass.

 I am considering doing a complete redesign on it for my next build.   Right now, it really isn't the safest laser out there. 

What would I do different?
1. totally separate the gas in/out from the electrodes. For simplicity, this one used a simple sharkbite fitting, and to get power into the system you simply clip the power supply onto each end.

2.  I would probably go with a larger diameter tube for the laser itself, this one is ok, but I think I can do better

3.  I would build the cooling jacket out of plexiglass/lexan instead of  pvc....  save the hastle of using a window, and give it a square profile.... this isn't a huge thing, more aesthetics than anything.

I will post up a video as soon as I get it working... "reliably" :>  a.k.a.   not blowing up due to overheating.

Yeah, I know I should date the posts on the website.

The first firing I did get a picture of, as you can see, there is a leak in the system and it took a bit of work to find out exactly where and how to fix it without a total rebuild.  Turns out it was in the OC optics.... and an additional gasket fixed it.

This was with no gas, just firing it up to see if the tube would glow... with a proper vacuum, it should be pink, not purple.






As soon as the epoxy cures properly, I will give it another go... this time with video recording, just in case   

[ThunderSqueak]

would finer thread pitch hardware make alignment easier?

have you ever tried brazing?
-sj

Yes, it probably would make alignment easier, but what I have right now works just fine.  The goal was to see what I could do "on the cheap" with what I had on hand. 

Yes, I have tried brazing, I just was again using what I had on hand....  which was a simple butane torch and some solder   The other choice was going ALL epoxy .... 

JB weld... wonderful stuff

At least I didn't use this, for some truly redneck performance



But then again.... that gives me an idea 

[sonicj]

agreed, jb weld is the good stufff! i have to put on my hazmat gear to use it though....  epoxy sensitivity sux big time!

your laser is sweet btw!
-sj

[slateraptor]

As soon as the epoxy cures properly, I will give it another go... this time with video recording, just in case   

Fo sho...and make sure your cuteness makes it into the video too.

[KTP]

I saw this thread a bit late and it looks like you have most or all of your needed parts, but if not, I have a ton of leftover stuff from years of collecting (at one time I had over 40 different CO2 lasers but now just a few Synrads RFs and some sealed HVDC glass tube units).  I do have a complete OC and HR assembly in adjustable mounts and a bunch of ZnSe lenses of different FL if you still need anything.

I still have a goal of building a homemade RF excited CO2 laser, mostly because it has never been done before by a hobbyist (to my knowledge).  I got rid of my tank of helium though...

edit: nevermind...I see you were trying for the complete hardware store solution.  Polished copper would have probably worked for the OC and HC then...CO2 lasers have such a high gain they will lase off anything. 

I wonder if you could build a vacuum tube radio using just parts from the hardware store....resistors, capacitors, transformers easy to make, but the vacuum tube would be a neat trick.