CO2 OC mirror and water...

[Pieznice29]

Just after setting up my co2 laser (Its normally sitting in the box it came in) I did a quick test on the coolant system, I turned on the water pump and sure enough water started to flow through the tube. Everything was fine, for about 5 seconds... The hose connecting to the tube at the output end popped off and sprayed water everywhere, I quickly turned off the pump.

Now heres my problem:
The OC mirror got soaked, I dried it off as quickly as I could though.
Have I wrecked the mirror?
I'm not sure on how reactive germanium is with water, google seems to tell me it does react slightly. I noticed there is a small slightly white spot in the center of the mirror that is less reflective than the rest of it. I've never noticed this before but the fact that it is in the center leads me to believe that it is damage caused by normal use of the laser and not this brief contact with water.

If I haven't completely ruined my laser, what should I do?
Try and clean the mirror? Give it a few days to dry?
I'm a bit scared of turning it on incase the mirror self-destructs...

Thanks in advance

 

[Cyparagon]

It will be fine. If it has water spots, clean it like you would other optics.

 

[Pieznice29]

Ok, thanks. I thought the same, but didn't want to risk it just incase.

 

[Meatball]

Just after setting up my co2 laser (Its normally sitting in the box it came in) I did a quick test on the coolant system, I turned on the water pump and sure enough water started to flow through the tube. Everything was fine, for about 5 seconds... The hose connecting to the tube at the output end popped off and sprayed water everywhere, I quickly turned off the pump.

Now heres my problem:
The OC mirror got soaked, I dried it off as quickly as I could though.
Have I wrecked the mirror?
I'm not sure on how reactive germanium is with water, google seems to tell me it does react slightly. I noticed there is a small slightly white spot in the center of the mirror that is less reflective than the rest of it. I've never noticed this before but the fact that it is in the center leads me to believe that it is damage caused by normal use of the laser and not this brief contact with water.

If I haven't completely ruined my laser, what should I do?
Try and clean the mirror? Give it a few days to dry?
I'm a bit scared of turning it on incase the mirror self-destructs...

Thanks in advance

Hey,

May I see a picture of your setup? I've got a 35W on the way here, and would like to get an idea of how big of a water pump I should pick up..

Thanks,

-Tyler

 

[Pieznice29]

May I see a picture of your setup?

It's a 40w tube from coletech(ebay), homemade power supply and water pump is:
12V DC CPU Cooling CAR Brushless Water Pump DC40A-1215 | eBay UK
Although its a 12v pump I usually run it at 5v and haven't had any overheating issues with the laser, yet.

 

[Things]

I believe my CO2 has a little white spot in the center of the OC, however it doesn't seem to affect the performance at all.

 

[Pieznice29]

I believe my CO2 has a little white spot in the center of the OC, however it doesn't seem to affect the performance at all.

I remember when I first got it the OC was a perfect mirror, seems to be somthing that occurs from usage. Good to hear it's normal. :thanks:

 

[Alexizupinhea]

Hey,

May I see a picture of your setup? I've got a 35W on the way here, and would like to get an idea of how big of a water pump I should pick up..

Thanks,

-Tyler

Ebay has some ones they show for CO2 lasers. Generally it doesn't heat up the water THAT quickly. They are small tubes and don't need a very large pump. What is more important is to just make sure you have a reservoir of maybe a liter or more with access to air. I don't think you would need radiator w/ a fan unless you planned on running it continuously for several hours. Of course, I only have a 25W, so maybe a 35W would be slightly different.

 

[Pieznice29]

They are small tubes and don't need a very large pump. What is more important is to just make sure you have a reservoir of maybe a liter or more with access to air.

I just use a small plastic tub with about 2 to 3L of water in, so far i've never been able to heat it above about 35C or so even with 5 to 10 minute runs at full power with a 40w tube. It always amazes me just how much energy it takes to heat water...

 

[Things]

When you think about it, for a 40W tube, you're pumping roughly 360 watts into it. Only 40 of that makes it out as laser light, the other 320 watts is dumped into the water. Considering an average kettle (At least here in Aus), is rated for 2200W and still takes a minute or 2 to heat up that small amount of water, the amount of heat coming off the CO2 tube is very little.

It's all about just moving it away from the tube, not because they generate so much heat they need water cooling

 

[Pieznice29]

It's all about just moving it away from the tube, not because they generate so much heat they need water cooling

Yep, I bet it would be possible to air-cool CO2's just like argon lasers if you wrapped a big heatsink around the bore of tube and pointed a rather large and noisey fan at it. I suppose water cooling just provides convenience in the tight spaces where these tubes are normally used.
Well, that is until a pipe blows off and gets your OC mirror wet :na:

 

[james1095]

I use a small fountain pump with my 25W CO2. I need to make a proper reservoir at some point but this works fine for intermittent use and when the water starts to get warm I dump some ice cubes in the jar.