I had issues with condensation on my laser tube when i had colder water temps than room temperature.
I did a lot of testing with different solutions, but the one that worked pretty good was installing fans at the end of the laser tube.
If you have a properly configured exhaust, sealed machine and smoke assist – this modification will not make wonders with your setup – it will help a bit though!
Read more here about smoke assist and how to seal your machine properly.
A fan on the laser tube?
The laser tube is the main part of your laser machine.
When in use it generates huge amount of heat inside the tube, which most is carried away by the water cooling.
But, your inside temperature, the water temperature and the laser tube temperature will create heat inside the tube compartment.
If you are in a very humid place, or where you have higher indoor temperatures you might get condensation on your tube, similar can happen when you have a very cold coolant flow.
Perfect water temperature on the coolant is roughly 12-15c – you do not gain anything by having it lower just adding risks for cracking the tube or creating condensation.
Remember, the air you push in to your laser tube compartment can never “cool” anything lower than your ambient temperature, and when the tube is working it´s always hotter than ambient so it´s always a win-win situation with fans.
The setup and parts you need
As there is different machines out there, some has a lid for a longer tube – others do not. If you do not have this removable lid you need to cut a hole for the fan.
– One 80-120mm computer fan, 12v
– Rubber seal, hot glue or similar around the fan so its sealed to the panel
– 12v power supply (1A is enough, a old wall wart will work)
– Screws or bolts to install it
Do not go overkill on flow, you just want some air pushing in over the laser tube. The exhaust will pull the air from the beam “hole” and out the exhaust.
If you have too much input here, you will disrupt the exhaust function and might push smoke outside your machine instead of out the exhaust.
In this example i have used high pressure fans made for computer water cooling.
What results can you expect?
I have a K40D in my example shown above, my ambient temperature is 20-24c and my water temperature on the coolant is always between 14-15c cooled.
After running this fan for a year almost now, i have noticed a lot less condensation on my laser tube (which can cause arcing or shorts).
The exhaust will pull air from your machine naturally – but adding a fan will help it by pushing the air in to the bigger compartment. Make sure to seal your lid for the laser tube with window rubber strips or similar.