What kind of water do I need for a laser cutter?

There are three types for a laser and two of them you shouldn't use, Tap water, deionised water and distilled water. The short answer is use distilled and there are reasons. I'll go through the different types and explain the differences and when they are used.

Tap Water.

You'll often see videos of laser cutters running on tap water with some ice in it. If you want to use it and you have nothing else then do so at your own risk and you'll need a supply of ice. The main issues with tap water is they have minerals and organisms in them. Firstly I'll address minerals. Minerals increase the conductivity of water and (depending on the power of the laser tube ) you could have anywhere between 15 Kv ( 15,000 Volts ) to 50 Kv. If you think about the sockets in the UK are approximately 230 V thats a lot higher, and whilst everyone says the voltage wont kill you at that voltage it will leap around and try to find its way to ground. The reason for this is the gas in the laser tube needs to be 'excited' to create the laser beam and that needs a high voltage.

So now lets imagine there is water flowing through the middle of the laser tube to keep it cool. If the tube cracks and the water and the electric mix and its flowing where it shouldn't there is a possibility you could be electrocuted.

Moving on to the bacteria etc in tap water, if left exposed to the air water can get alage and mould growth and this isn't good for the water flow around the laser system.

Distilled water.

Lab Pro States:

' Distilled water is produced by condensing steam from boiled water and then collecting the condensation. This process can remove certain bacteria and substances, though it does not typically remove dissolved solids or minerals. Since distilled water has a neutral pH, it’s called “purified” water but not necessarily pure. While distilled water may be filtered to improve taste, it is most pure in its natural state, which makes it safe for consumption and suitable for general uses such as car batteries and irons.

Distilled water is often referred to as deionized water, although the terms are distinct.'

Distilled water does not conduct electricity as shown in this you tube video https://www.youtube.com/shorts/OY3dYbE0QMg

Deionized water.

Lab Pro goes on to say

'Deionized water is created by either passing water through ion-exchanging resins or other media, or exposing it to electric current. This process removes minerals and ions that contribute to conductivity in regular tap water. However, some of the available methods are not as effective at removing certain compounds like fluoride, nitrate, and chloride; therefore, advanced filtration systems are needed to make sure the water is safe for drinking. Distilled water on the other hand, is usually boiled and turned into vapor (steam). Once cooled down, impurities have been separated from the steam which results in pure H2O — not de-mineralized.'

and..

'Deionized water and distilled water are both considered “purified” and safe for consumption, though deionized takes it a step further. By being run through a deionization process, the water is stripped of its ions which can contain minerals and salts. This means that the remaining water is much purer than that of distilled water as all trace elements have been removed. Typically, this type of water is used in industrial and scientific applications or for extended-use applications such as steam irons or leather conditioning.'

What's wrong with using Deionized water?

Both Distilled and Deionized water immediately begin taking in impurities and minerals from the atmosphere and any material they are in contact with. Although I have never seen it, its theoretically possible that deionized will leech the minerals and ions from a chiller. Effectively rotting it from the inside.

Therefore Distilled water is the one to use.

If Distilled and Deionized are taking impurities from the air and elsewhere does that mean they are immediately impure?

Yes it does, and unless you get it straight from the source if will immediately begin to increase its conductivity. All we are really doing when using distilled, is reducing the conductivity and reducing the bacteria in the water so it lasts longer.

Antifreeze

This complicates things further because adding antifreeze adds impurities to the water and increases the conductivity. we start by worrying about the impurities and add in impurities to stop it from freezing!

That's why we use a specially designed antifreeze for coolant systems Coolflow DTX

It's only available in massive drums though, unless you buy it from somewhere like here:

https://laserply.co.uk/product/laser-antifreeze-coolflow-dtx/

Why your laser tube isn't firing in the summer.

The UK summer didnt really turn up this year did it? That said, in previous years it's been pretty hot. I find that often people keep their machines in garages or warehouses. Places that are susceptible to extremes of heat.

This is a problem for co2 laser tubes. Laser tubes work best between 15-25 degrees C according to the manufacturers. Your lovely metal roof and uninsulated walls are soaking up all the heat in the summer. A lot of garage laser cutters either have a bucket of water as a cooler or a CW3000 'chiller'. That's fine for small machines like a 40 watt generally but at 60 watts and above things tend to get a bit hotter. That bucket of water and the CW3000 doesn't have any kind of refigerator in it. It can only chill to the ambient temperature of the room ( unless you keep giving that bucket of water some ice ). In the summer if your garage is getting to 30 degrees you have a problem. Signs of an overheating tube are the power will slowly drop off until the beam stops. The tube will also be at least very warm to touch. If this happens enough times then it will likely damage the tube. For this reason I recommend people buy a CW5200 chiller from somewhere like

https://laserply.co.uk/product/cw5200-water-cooler-genuine-sa/?srsltid=AfmBOordPCc4Fn9c2YMoAjgkSDtA8OkJNq27SIeNWkvHINHbThK2lgr6

https://hpclaser.co.uk/p/cw5200-water-chiller/

https://mantechparts.co.uk/products/sa-cw5200th-chiller-system-for-co2-lasers-genuine-product?srsltid=AfmBOooW8ZY5kRUXIrFIGP04ro_fqMvpHFQOI8l6ChTWO3sW2moc_Mae

Its an upgrade on the CW3000 chiller as it has an actual refrigerator in it. They aren't cheap but replacing a laser tube and fitting it is more expensive if they keep breaking.

What type of Laser Cutter should I buy?

This isn’t a complex question really, I’d say buy a second hand laser cutter and then get Studio T to repair or service it. They often come with software called RDWorks which is ok, but isn't great. You can purchase a newer and user friendly piece of software called Lightburn, which is much easier to use and supports a variety of machines. For a DSP licence it's around £96 and this allows it to be used on three computers. You can renew the licence every year for updates or just stick with the version you have if you don't renew. Note this software doesn't work on Leetro controllers.

Why is that?

Laser cutters haven’t changed much in their design in many years and most of the Chinese built lasers like Boxford, HPC, ThunderLaser haven’t changed much, if at all. The parts for these machines are also available from ebay and Amazon for much cheaper than the Laser Company will sell them to you. They will tell you the parts you are buying from the internet are inferior and theirs are better quality. This may be true, but not worth the price they are charging.  Sometimes it’s unavoidable to buy these parts from the original company and some can be reasonable, but certainly for lenses and mirrors this is not true. The exception to this is with ThunderLaser, who we work closely with and can pick up parts on our way to you.

What kind of Laser Cutters shouldn’t I buy?

It depends. If you want a machine that’s very quick at engraving, machines like Universal, GCC, Trotec are fast. However, they are expensive and use closed wall proprietary systems. Often the parts are only available from the original seller and are very expensive. You can easily expect to pay £800-£1200 for a new controller, £500 for a motor and fitting is on top.

In addition to this, there is the thorny issue of the air cooled Co2 Laser with these machines. When they run out of gas, you can pay from £3000 upwards for a re-gas. Sometimes, if the machine is old, the re-gas company will refuse to re-gas it and tell you need to buy a new laser unit. This can be around £10,000. They don’t tell you this when you buy a machine. This is especially a problem for schools as they can buy a whole new machine for less.  Factor this into your budget every year if you want to keep the machine.  In contrast to this, a 100 watt laser tube that fits in an HPC etc would cost around £500. Finally some of the software and controllers for these machines haven't been updated in years and are still being sold with it.

There is one other type of laser cutter I wouldn’t buy. The cheap Chinese machines – usually red and black with a warning sticker on them that doesn’t make any sense. You can take a complete risk with these machines and get a good one, or a Friday afternoon machine and it will be an absolute nightmare. You’ll end up throwing money at it and it will never work reliably.

What if I still want to buy a laser cutter new for VAT reasons etc?

If you want established brands, you cant go wrong with the previously mentioned HPC, Boxford and Thunderlaser. You get UK support free for a year to begin with. The components tend to be the same but with these machines the chassis is the key and they are solidly built. If you want to, buy a new machine, get the free years support and once the year has expired contact us. Why would I do that you ask? HPC and Boxford often will quote, for example, £600 but tell you they cant come for 4 weeks till they are in the area. Studio T usually works on a week to two weeks schedule.

Which Laser Cutters are the safest?

All of the previously mentioned are the safe. Boxfords particularly have complicated relay system. It’s a beautiful piece of engineering but it seems a little over engineered.

Can I expect any issues with these machines?

Flow Sensor.

HPC and Boxfords water flow sensor often break so the laser wont fire.

Autofocus.

The auto focus on Boxfords tends to break but this isn’t a design fault. This happens on all auto focus machines. When the machine switches on, it homes and drags the tip of the auto autofocus probe through the honeycomb bed.

Red Dot.

The red dot, I hate the red dot. They always break, they aren’t really necessary when you have been using the laser cutter long enough, but they always break on all machines.

Chillers.

Boxfords have the chiller in the back of the machine sometimes and if you want to change the water this is a bit of pain. My main criticism of HPC is some of their 80 watt machines are sold with a water pump and plastic tub for the water that cools the laser tube. I really don’t know why they don’t just increase the price slightly and sell them with a chiller. All Laser companies sometimes sell their laser cutters with a CW3000 chiller. Like a bucket of water, this will only cool to the ambient temperature in the room. If your environment gets to 30 degrees C in the summer because of a metal roof, your chiller will be at 30 degrees C and this is too hot for the laser tube. You are far better off buying a CW5200 which is real chiller.

Adjustable beds.

Most laser cutters come with a bed with adjustable height, they are a little useful if you engrave things like boxes. If you use them often they always seem to go out of alignment and aren’t parallel to the laser head after a while. This is for all laser cutters, not just the ones mentioned. I prefer to just adjust the barrel height and to the material.

Winter, freezing and thermal shock.

Water starts to expand at around 2 degrees when the temperature starts to drop to freezing. This can crack the co2 laser tube. You can avoid this buying laser friendly anti-freeze. Great I hear you say! It isn’t quite as simple as that. If the temperature is below 10 degrees C and you start to use your laser cutter to cut through some 6mm material the temperature can drastically increase; the change in temperature cracks the tube (thermal shock) and you have a dead tube. Optimum operating temperature for a laser tube is at least 15 degrees C, although you can get away with around 10 degrees C, just warm the tube slowly by either having an inline aquarium heater that you can switch on temporarily or use it on some light engraving.

Summer, insufficient cooling and forgetting to put the chiller on.

If you have a CW3000 chiller or a bucket of water and it's hot in the room, once the Co2 laser tube gets above 30 degrees C you may see the power decrease to the point that the tube stops firing. Co2 Laser tubes ideal maximum operating temperature is 25 degrees C. This isn’t necessarily a problem once or twice, but it can break the tube completely.

A note about fume extractors for laser cutters.

If you can, extract the fumes outside through a wall or window but not somewhere where they can blow back into a room or affect others outside. Filters cost around £500 a set and there are usually two - the pre filter and combined filter. According to BOFA technical support the combined filers should be changed every year because they are hygroscopic and will absorb moisture from the air. If they are full of moisture they can't absorb the fumes. If within a year the fume extractor shows as full, first change the pre filter. If the extractor still says full change the combined filter. However, it's best practice to change both at the same time.

It is up to you if you want to take the risk of using the filters for more than one year. If you you have an environment where several people could breath in fumes - there could be a H&S issue and it may affect your insurance. We would advise you to factor in a filter change into your budget every year. We can do this for you if you don't feel confident, but it is a simple job and can be done by anyone. It is not a technical job. Sometimes it may be ideal to combine this with a yearly service and we would only charge for the filters on top, no more than just a service.