CW-5000 Filled with Anit-Freeze?

[Justin Stark]

The manual says you can fill it with anti-freeze but I am just curious if anyone does and have had success. I'd like to fill it with anti-freeze for the winter just in case.

[Keith Downing]

I haven't personally had to use it given our climate, but I believe the consensus is to use RV Antifreeze. And to use about a 25-35% ratio.

[Kev Williams]

As an RV and boat owner very familiar with RV anti-freeze, yes it works well to protect RV water lines, but at around 10°F (-12°C) the stuff starts turning to slush. Ok for 'static' water lines as it won't expand until around -50° F, but I'm not sure how a C5000 will react to pumping it. If you never expect to get that cold then RV/propylene glycol antifreeze should be fine.

[Keith Downing]

Interesting information Kev. I, of course, am only going off the recommendations I've read here and on some other forums, but the general consensus (dozens of posts at least) seems to be that you need to use the RV antifreeze because it is non-toxic. And that the normal antifreeze doesn't play well with the laser tubes, especially in higher concentrations.

Have you used the regular stuff with success? Or are you lucky (like me) not to have ever had to test it? Lol

[Justin Stark]

The manual says to use non-corrosive anti-freeze but it doesn't give an anti-freeze to water ratio. Are you saying to use 25% RV Anti-freeze to 75% water? I have no had any luck finding other threads that discuss this topic. If you can point me to those, that'd be awesome!

[Kev Williams]

Me, I use only distilled water in my chiller, but I heat my garage shop, no need for antifreeze.

Just did a little research, and some copy/paste --

ETHYLENE glycol, "car" antifreeze, is corrosive, so it has corrosion inhibitors added, often these are silicate based rust inhibitors that can coat and/or clog heat exchanger surfaces...

PROPYLENE glycol, "RV" antifreeze, oxidizes when exposed to air and heat, forming lactic acid.If not properly inhibited, this fluid can be very corrosive,so pH buffering agents such as dipotassium phosphate and potassium bicarbonate are often added to propylene glycol, to prevent acidic corrosion of metal components...

And for what it's worth, METHANOL is good antifreeze, but is also corrosive...

SO- basically, antifreeze is corrosive- or not, and may plug up your chiller's heat exchanger- or not --I'm thinking that if AF is changed out for distilled water in warm months the chiller would wear out before antifreeze will ever hurt it!

choose your weapon

[Jerome Stanek]

I have been running straight RV antifreeze in my lasers for 4 years now and have not had any problems

[Keith Downing]

The manual says to use non-corrosive anti-freeze but it doesn't give an anti-freeze to water ratio. Are you saying to use 25% RV Anti-freeze to 75% water? I have no had any luck finding other threads that discuss this topic. If you can point me to those, that'd be awesome!

There is always some debate, but to be clear yes my suggestion was in the range of 25%-50% RV antifreeze so 75-50% distilled water. Now obviously, the protection of the antifreeze does begin to drop at some point as you dilute it and you may want to check the manufacturer's suggestion based on your expected temperature range. But I'm assuming you aren't going to let your machine drop into temperatures significantly below freezing (like single digit temps or below).

Here's an old thread on the subject from SMC: https://sawmillcreek.org/showthread.php?73322

And then this topic comes up about once a week on the FB groups I'm in. Can't link to those directly though.

Edit: after a little more research, it seems like the most commonly recommended ratio is 50-50 RV antifreeze and distilled water.

[Keith Downing]

Here's one more link confirming RV antifreeze as well: https://sawmillcreek.org/showthread....iller-Question

I wish I could find some of the conversation regarding the reasons diluting it was better. I believe it had to do with the theoretical non-conductivity of distilled water. But don't quote me on that.

I have also seen it mentioned that pure antifreeze may heat up faster than water. Haven't verified that either though.

[Fred Britt]

Our Camfive Laser, the mfg states to use 50/50 antifreeze. I flush the system every six months as per the manual.

[Rich Harman]

I would not use antifreeze at all unless there is a risk of freezing.

If you do need to use antifreeze, use no more than recommended, antifreeze is not as good for heat transfer as water is. The more antifreeze that you mix in with water, the less heat the mixture can absorb.

A couple years ago I installed a water filter on the line. It seems to be working well on keeping scum from forming in the tube. I change the water maybe twice a year. On the few days where it may get below freezing in my shop I make sure there is a small space heater aimed at the laser. I doubt it is actually necessary but it gives me some peace of mind.

[Justin Stark]

Thanks for all your suggestions. I plan to try the 50/50 mixture. My last issue to solve for operating in the winter is maintain proper ambient temperature inside my shop. My shop is essentially a 10x20’ insulated shed (except the floor, I messed up there!). When I turn the blower on it sucks all my climate controlled air out and is replaced with outside temp air through small cracks/leaks throughout my shop to even out the pressure. To solve this, I was going to run tubing from my shop window to my house window (only ~10 ft run) so the replaced air is also climate controlled. However, I fear my glass laser tube will be cooler than the replaced air And create condensation on it. Maybe the temperature fluctuations will be gradual enough this won’t be an issue. Or maybe I can rig up an insulated blanket to keep on the tube when it’s not running to keep it warm. KC can get pretty cold in the winter so I don’t plan on keeping the shop temp as warm as my house ($$$)

[Bill George]

When I used RV anti Freeze (open system) it would scum up or get algae. I went to a real mild mixture of automotive anti freeze that had inhibitors to protect aluminum and a touch of bleach added. Yes it does not transfer heat as well as plain water, but those of up here in Winter Wonderland have no choice. Yes I have heat in my shop, but have you ever heard that if might fail!! Or a gas main might break or power goes off, it happens.

[Keith Downing]

When I used RV anti Freeze (open system) it would scum up or get algae. I went to a real mild mixture of automotive anti freeze that had inhibitors to protect aluminum and a touch of bleach added. Yes it does not transfer heat as well as plain water, but those of up here in Winter Wonderland have no choice. Yes I have heat in my shop, but have you ever heard that if might fail!! Or a gas main might break or power goes off, it happens.

Interesting. In my research it seemed the automotive antifreeze commonly resulted in the algae buildup (and is also corrosive). The RV antifreeze is supposed to be the solution to that problem ironically. I believe there are two different chemicals used for that stuff though. Maybe one is preferable.

Also, I used to do the bleach every few weeks until I watched it eat a hole through a copper pipe. And the concentration was only about 20%. So be careful if you go that route for algae control. I wouldn't have believed it if it hadn't happened to me.

[Bill George]

If the new automotive anti freeze is corrosive someone needs to tell the car manufacturers that. Modern anti freeze contains additives to prevent corrosion and if you get the right stuff made for aluminum engines it has that protection also.