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Justin Stark
12-20-2018, 9:17 PM
What is the minimum operating temperature you recommend for running laser engraver? I am operating in a 40degF shop and the chiller is at 7-10degC, just curious if anyone knows if operating at lower temperatures reduces the life of the laser tube more quickly...

Doug Fisher
12-20-2018, 10:04 PM
Go to the website for your tube's manufacturer and look up the specs for you exact model. Most companies post a temp range in the specifications.

Jerry Wright
12-21-2018, 2:49 AM
My Ten-High CO2 laser guideline is minimum of 4C or 40F.

Justin Stark
12-21-2018, 8:54 AM
The recommended operating temps for the Reci is 2-40C which is a wide range. Surely there is an ideal range within this recommended range that is better for the life of the tube. I was just curious if anyone knew if operating at 2C was any different than 40C in terms of laser tube life.

Jerome Stanek
12-21-2018, 10:06 AM
My chiller is set at 20 C for my laser

Jerry Wright
12-21-2018, 6:42 PM
I never run above 20C. Lost a tube at 24/28C, but I also had a kinked cooling line.

Michael Henriksen
12-23-2018, 6:27 AM
My workshop can reach freezing temps in winter. I keep the coolant water circulating all the time and have an 80W aquarium heater in the water tank. That keeps the temp above 10C.

Clark Pace
12-23-2018, 4:26 PM
Yep I run anti freeze in mine and run the water all the time. It gets cold in my shop. But laser still operates find. Cross my fingers

Justin Stark
12-24-2018, 11:20 AM
Thatís a great idea with the fish tank heater!

Jerome Stanek
12-24-2018, 12:47 PM
On my old laser I had a farm watering bucket that keeps the water at about 50 F

John Noell
12-24-2018, 3:54 PM
Dave Sheldrake (who is VERY knowledgeable) said, "Beam profiles change in DC tubes when they get hot, the window to operate a DC tube efficiently with a stable beam is only +/- 1.2 - 2 degrees. On a narrow body tube it should be kept between 20 to 24 degree's (on a wide body, 17 - 21 degree's). Hit 24 on a narrow body and you will start losing tube life exponentially as it goes above that. Temperature stability is absolutely essential in DC tubes."

Justin Stark
12-28-2018, 8:52 PM
Thanks for the post, John. In my research on the topic, I have seen a lot of posts to not go over the recommended zone in fear of decreasing the life of the laser but I haven't seen anything on cooling the laser with 7-10 degC water. I found an older thread where Dave said the following:

It's a strange problem with thermal shock and DC lasers (water cooled versions)

The problem comes from temperature change / time in most cases.

Start up at 12 degrees won't be a problem unless the tube/coolant is at a far higher temperature than that when the fluid starts to cycle. If say the tube glass is at 75 C and you dump water through it at 10 C it's probably going to shatter, the same the other way, if the tube is at 10 and you fire 70 degree water through it, it's probably going to shatter.

The problem is the ends of tubes are subject to some pretty savage heating when the tube fires so tube type will also be a factor. To be honest the bigger danger will come from the temp change affecting the epoxy they use to bond the jackets on to some tube types (cheaper tubes)

Short version? starting up with the water at 12 so long as the rest of the tube isn't already hot won't be a problem (I've started a few of mine with the water at 6 - 8 and had no problems) (my chillers are all set to a base line of 15 degrees)

ps: Johns idea will work well, run the chiller for 5 minutes before you start the machine, on mine the chillers are never turned off and run 24/7 even if the machines aren't running as the pumps put a little bit of heat into the water