I have been having a look around this morning on ebay & the likes

Lasers
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I have been having a look around this morning on ebay & the likes for some components for monitoring the temperature of my water going into the tube & as it gets out of the tube. I am trying to find something that is either located in Australia or ships here free (or relatively cheaply). Anyway, I came across this seller who sells the following things that I thought might be useful to me & anyone else.

http://www.ebay.com.au/itm/DC-12V-10A-Intelligent-Digital-Display-Thermostat-Temperature-Controller-Switch-/281842870176?hash=item419f24e7a0:g:GMgAAOSw1vlUrOQu

& this other one

http://www.ebay.com.au/itm/Digital-Time-Voltage-Dual-Temperature-Display-Module-for-Car-interior-wate-tank-/281856099378?hash=item419feec432:g:Fm8AAOSwFnFV9s81

Anyone (more electronically-minded than me) know whether it’s worth giving these a try?

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The small glass tube output end is where i cracked my tube when i forgot to turn on the water pump,i find that 15 to 20 deg is the best temp

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@Phillip_Conroy That’s unfortunate that you cracked your tube. I thought I best start sorting out some sort of temperature monitoring as it is getting well & truly into summer here & looking to get 40 degree C days I imagine.

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Here’s what I ordered for mine. Not needing control, these will give cheap monitoring once the thermistors are fitted into a couple of plastic barb tees.

You get a temp in and a temp out for under 10 bucks. I made my living in industrial controls for over 40 years, and just couldn’t justify fancier equipment.

I do have an old Ranger data logger I may hook to it temporarily to make sure there no spikes or odd happenings going on, but once that’s done, the only other thing I might want would be an overtemp/low flow alarm/shutdown.

http://www.ebay.com/itm/371108188641?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

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You can also get them on aliexpress for around $5.

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@Scott_Marshall Thanks Scott. I saw that style of temperature gauge while I was looking around too. As @Richard_Vowles says, you can find them on aliexpress cheaper. I actually found them on aliexpress for about $1 each.
http://www.aliexpress.com/item/Digital-LCD-Probe-Fridge-Freezer-Thermometer-Thermograph-Meter-for-Refrigerator-110C-Black-White/32455167342.html?spm=2114.01020208.3.91.CDHmGb&ws_ab_test=searchweb201556_2,searchweb201644_4_79_78_77_82_80_62_81,searchweb201560_5

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Water flow is more impotant than temp as a tube will only last 10 min with no water flow and high temps will just lower the laser output power temparaly )

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@Phillip_Conroy Thanks Phillip. Does that water-flow switch reduce the water-flow at all? I am unsure from the picture what is actually inside it. Looks like a good investment though. As you said, no water flow is going to be a serious problem.

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The water flow switch lowers the flow,i just used a better bigger pump,ps water tank must be same level as the laser cutter to prevent air pockets,and water flowing out of tube when pump is off

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@Phillip_Conroy After doing about 4 hours worth of cutting I noticed that the performance of my K40 dropped considerably. The water exiting the unit was warm to the touch and the reservoir was lukewarm. Do you know what sort of performance impact I should expect? I was finding that it was unable to cut 3mm acrylic even at 20mA.