Cooling system tubing

Methods of cooling laser tubes

Cooling system tubing

Postby buildsomething » Fri Feb 19, 2010 3:39 pm

In cooling my system, I was using the light brown surgical tubing found at most DIY stores, but I am finding that it does not have the wall strength needed to go around sharp corners causing wall collapse and water flow restriction or worse total shut off.

I like the whitish opaque tubing used within the CO2 laser sections and I see it being used in some of the commercial machines, but I was wondering if anyone has any of that stuff that they would like to sell. I need about 18" - 24" max at 3/8" id. A foot at each end of the laser is all I need. Those pieces would be used to connect to the laser and then exit the machine. From there on in I can use other stiffer tubing that I have that will go to the pump. I didn't want to use the stiffer tubing that I have for fear of breaking the spigots at the tube end, while trying to force them on.

I haven't been able to source that material here at a reasonable cost....ie....going to the lab distributors...they want an arm and a leg for that stuff. I think the tubing might be called TYGON...but I'm not sure.

In the mean time, I will use the surgical tubing that I have to get me by.

Richard
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Re: Cooling system tubing

Postby bdring » Fri Feb 19, 2010 7:19 pm

I use that same tubing and yes, it is very sensitive to kinking. I have it carefully routed and keep an eye on, but I would not recommend it. It is very easy to attach to the tube though :)

My tube came with that milky white tubing on it to connect the various cooling circuits. It started to leak and when I removed it, it sort of fell apart as I removed it. I pulled out all other pieces of it.
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Re: Cooling system tubing

Postby lasersafe1 » Sat Feb 20, 2010 1:58 am

Most of the tubing that is relatively clear can be heated with a heat gun and it will stretch quite easily to slip over a fitting. Wear gloves. Sometimes you can just use a similar sized object to get it close. Once the tubing cools it will retain the new size. You don't necessarilly need to stay with "clear" tubing, as long as you have a flow sensor. Most home stores have assorted rubber tubing, and there is also a stiff poly tube used now for drip irrigation systems that will kink if bent sharply, but it will not collapse on its own.

Oh, I just read your post again. You are looking for the soft stuff that goes right to the laser tube. I agree that you don't want to force it, so the surgical tubing should be a solution. They are not using any brand of Tygon that I'm familiar with. The Tygon has absolutely no stretch, unless heated as I mentioned above. I can send you a few feet of Tygon. Give me your address in a private message.
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Re: Cooling system tubing

Postby Ben » Sat Mar 20, 2010 1:21 am

Tygon is definitely one of the best choices for tubing. Then it just depends on what type of Tygon tubing you want; for this application Tygon A-60-G (Norprene) or Tygon R-1000 (Ultra-Soft) would be ideal.

You could use some Anti-Kink Coils to prevent the tube from kinking. Every brand/size of tubing has a different bend radius before it kinks. I’ve never had any kinking issues when using anti kink coils.

Available here (in various colors!): http://www.koolance.com/water-cooling/default.php?cPath=80

What size of tubing is everyone using on the Chinese glass tubes? It sounds like some people are using 3/8” ID. Since the barbs on the tube are 10mm OD (3/8”) wouldn’t 1/4”ID be more ideal?
-Ben

My Lasers:
40w CO2 Laser (Chinese Glass Tube), Directed Energy Inc. 30w RF CO2 Laser (Needs Repair), Laakmann Electro-Optics 20w RF CO2 Laser (Needs Repair), 7-10w RF CO2 Laser
Coherent 12w 808nm FAP LASER DIODE
MELLES GRIOT He-Ne Laser
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Re: Cooling system tubing

Postby lasersafe1 » Sat Mar 20, 2010 1:15 pm

Yes, 1/4 Tygon is perfect for these tubes and can be resized on the fly by heating.
See this post: http://www.buildlog.net/forum/viewtopic.php?f=16&t=124&start=30#p557
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Re: Cooling system tubing

Postby Tweakie » Wed Apr 28, 2010 6:36 am

Being a RC flyer for many years I already had some silicone tubing which appears to be ideal. It does not kink and with the aid of a touch of washing up liquid slides easily onto the tube barbs. As belt and braces I also fitted small cable ties (just lightly tightened). Most of the model shops I visit sell this stuff in various diameters.

Tweakie.

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Laser fountain

Postby lasersafe1 » Sun Nov 14, 2010 1:35 pm

Started up my machine last night and heard a spray of liquid. Shut it down and removed the rear cover to inspect. The small tube that the factory installs on these Chinese tubes between the output lens and the main tube failed. You all may have already noticed that this tube is not the best. Mine almost looked like it had been chewed through from the outside. The propylene glycol coolant I use is sweet, so perhaps a mouse wanted a drink. I did not see any mouse droppings, so I don't know if that is what happened. If it was not a mouse, then perhaps there was a bad reaction between my coolant and the type of plastic used by the Chinese. The spray went all over my electronics and into the laser power supply while it was energized!! :shock: . I opened everything up and dried it with paper towels and a hair dryer.

To repair the tube I used a piece of Tygon. I replaced both input and output sides. My Tygon is the standard milk grade type B-44-4X. Once warmed in boiling water it is easy to bend and flex over the nipples. Leak fixed and I'm back in operation. - Got very lucky this time!! :)

http://www.tygon.com/tygon-traditional-tubing.aspx
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Re: Cooling system tubing

Postby bdring » Sun Nov 14, 2010 3:12 pm

Mine failed a while back too. The tubing was a milky white material that had the consistency of wax when it failed. I could peel of little pieces. I wonder if ozone is an issue. That can cause some plastics to fail. High voltage creates ozone, but usually only if there is an exposed arc.
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Re: Cooling system tubing

Postby lasersafe1 » Sun Nov 14, 2010 4:13 pm

We may never know. I think the big lesson learned is that all of us should inspect our tubing routinely, especially if we haven't replaced the original tubing with a higher quality tube. I was VERY lucky it didn't kill my electronics.

This should also be a lesson for the manufacturers. Spend the extra dollar and use some good Tygon in your systems because the tubing you are providing with your systems doesn't last.

I wonder how many Chinese engravers or tubes sold two years ago that are about to have this same failure?
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Re: Cooling system tubing

Postby macona » Sun Nov 14, 2010 6:51 pm

Like the manufacturers care. Once they leave the factory they will never see them again.

Probably the tube started loosing its plasticizers. There should be no ozone present in there. If it was everything steel would start rusting.
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