Enviro ET-120 air pump, the type we use as an air assist upgrade on our OMTech CO2 lasers

CO2 Laser Maintenance: Every Product We Use in Our Commercial Workshop

CO2 laser maintenance comes down to four things: clean optics, greased rails, clean cooling water and strong air assist. On our two OMTech lasers (both sold to us as 80W) that means cleaning the lens and three mirrors weekly, greasing the rails monthly and running distilled water in the chiller. It takes us about an hour a month per machine.

We've run OMTech CO2 lasers in daily production since January 2023, and two of them since June 2024, at our workshop in Buckley, North Wales. They run 5 to 10 hours a day, five days a week. Every product below is one we buy again and again because it works; no brand has paid to be on this page. Consumables come to around £50 a year at our 2026 usage.

The focus lens

The lens sits in the cutting head and focuses the beam to the fine point that does the cutting and engraving. In our experience a dirty or damaged lens is one of the commonest causes of poor cut quality, and one of the most overlooked.

We use the MCWlaser CVD ZnSe 18mm focus lens with a 50.8mm focal length. It fits both our OMTech machines, it's listed for 40W–200W CO2 lasers, and the quality has been consistently good. ZnSe (zinc selenide) is the right material for a CO2 lens: ordinary glass doesn't transmit the 10.6 µm CO2 wavelength, so don't be tempted by a glass lens.

Check your focal length before ordering. 2 inch (50.8mm) is a common focal length on desktop CO2 lasers, but OMTech sells lenses from 1.5 to 4 inches, so confirm it against your machine's spec.

Handle lenses with care: zinc selenide is toxic. Wear gloves or finger cots when you handle a lens, and wrap and dispose of a cracked or chipped one carefully.

The mirrors

A CO2 laser uses three mirrors to carry the beam from the tube to the lens. All three need to be clean and correctly aligned: a dirty mirror absorbs energy that should be cutting your material, and a misaligned one sends the beam off-centre.

We use MCWlaser 25mm gold-plated silicon CO2 laser mirrors, which come in a pack of three, one for each mirror position. Keep a spare set in the drawer: if you damage one during cleaning, you don't want to be waiting for delivery with a machine down.

Cleaning fluid

We clean lenses and mirrors with high-purity isopropanol (isopropyl alcohol, 99% or better, not 70% rubbing alcohol). At that purity it evaporates quickly and leaves little residue. Optics makers also approve lab-grade ethanol or acetone.

We use this isopropanol. Buy a sensible quantity: you'll use it every week, and it keeps well in a sealed bottle (left open, it evaporates and absorbs moisture from the air).

Never use household glass cleaner or anything with additives. Never touch optical surfaces with bare fingers, because skin oils contaminate the coating.

Lens cleaning tissue and technique

Optical surfaces need optical-grade lens tissue: not kitchen roll, not microfibre cloths, nothing abrasive. The wrong material scratches the coating, and a scratched lens is scrap.

We use these lens cleaning tissue papers: 700 sheets, sold for microscopes and precision optics. A few sheets per clean, one clean a week, so a pack lasts a long time.

The technique:

  1. Blow off loose dust with a hand bulb blower, not compressor air.
  2. Put a few drops of isopropanol on a fresh sheet of tissue.
  3. Lay the damp tissue on the lens or mirror and draw it slowly across the surface in one direction. Don't scrub, and don't wipe in circles, which can grind grit round the surface.
  4. Use a fresh sheet for each pass. If residue remains, repeat with a new sheet rather than pressing harder.

Rail lubricant

The gantry rails need regular cleaning and lubrication. We use Lucas Oil White Lithium Grease; white lithium grease is the type OMTech's help centre recommends for the rails. In our experience it stays put at speed and copes with a workshop's temperature swings. Apply it sparingly to clean rails. OMTech suggests every two weeks; we do it monthly at our usage.

Air assist upgrade

The built-in air pump on an OMTech does the job, but upgrading it is one of the most useful and least talked-about improvements you can make. More air at the nozzle means cleaner cuts, less charring, and a lens that stays cleaner between weekly cleans.

We run the Enviro ET-120 air pump on both machines. It's a linear-diaphragm pond aerator: pumps sold as ET-120 are rated at about 120 L/min, against the 30 L/min OMTech lists for the Turbo-758's built-in pump. The swap is a ten-minute job: unplug the air hose and electrical connection from the built-in pump and attach the new pump's air hose in its place. You'll need a reducer to match the hose diameter to your machine's fitting.

Warranty: OMTech UK's warranty terms (checked October 2026) exclude faults caused by not using an OMTech-supplied water pump or chiller, and alterations or servicing by anyone OMTech hasn't authorised. If your machine is still under warranty, check with OMTech before swapping the chiller, pump or other parts.

Why a pond pump rather than a compressor? A compressor puts moisture into the air line, which can contaminate the lens, so you'd need a water trap as well. A pond pump moves a lot of room air at low pressure, so there's no condensate to deal with. Ours runs all day, every day, quietly, with no trap needed.

Distilled water for the chiller

Not an Amazon link, but essential. Your chiller must run on distilled or deionised water only. Tap water leaves mineral deposits inside the laser tube over time, which restricts flow and raises the temperature. Supermarkets and motor-parts shops sell it cheaply.

Top up when the level drops. Our own routine has been a full water change once a year; Teyu, which makes S&A chillers, recommends changing it every three months, so treat that as the safe default.

Frost: if your workshop can drop below freezing, drain the system or use a laser-specific antifreeze coolant at the maker's ratio, and flush back to distilled water in spring. Never use car antifreeze, which is conductive and corrosive. Freezing water can crack the tube's water jacket, and OMTech doesn't cover freeze damage.

For everything about choosing the right chiller, read our laser chiller guide.

The full maintenance schedule

  • Weekly: clean the focus lens and all three mirrors with isopropanol and optical tissue.
  • Monthly: wipe down and re-grease the rails with white lithium grease (OMTech suggests every two weeks); check and top up the chiller water.
  • Water change: Teyu recommends every three months (we have done it yearly).
  • Winter: protect the cooling water from frost, as above.
  • Every job: run air assist; check the chiller temperature before starting; never leave the machine unattended while it's cutting, and keep a CO2 or ABC fire extinguisher within reach.

For the reliability record behind this routine, read our OMTech reliability post. When tubes and power supplies eventually need replacing, our laser tube guide and power supply guide cover what to buy and how to tell which part has failed. We also run a 2-hour training session, in person or by video call, if you want help setting up.

See the machines running

Both machines run every working day at our workshop in Buckley, North Wales, which is also an official OMTech showroom. Visits are free, informal and by appointment: email info@cherrygrovecraft.co.uk with a couple of dates. If you then order a machine, our OMTech discount code Cherrygrovecraft takes 4% off at omtech.uk (checked October 2026).

Frequently asked questions

How often should you clean a CO2 laser lens?
We clean the lens and all three mirrors once a week, with our machines running 5 to 10 hours a day. If cuts get weaker or the lens looks hazy, clean it sooner.

What should I use to clean CO2 laser lenses and mirrors?
High-purity isopropanol on optical lens tissue; optics makers also approve lab-grade ethanol or acetone. Blow off loose dust first, draw the damp tissue across in one direction, never scrub, and use a fresh sheet for each pass.

How often should I grease the rails on an OMTech laser?
OMTech suggests white lithium grease every two weeks. We do it monthly at our usage, applied sparingly to clean rails.

How often should I change the water in a laser chiller?
Teyu, which makes S&A chillers, recommends every three months, using distilled or deionised water only. Top up in between whenever the level drops.

Can I use car antifreeze in a laser chiller?
No. Car antifreeze is conductive and corrosive. Drain the system or use a laser-specific antifreeze coolant at the maker's ratio, and note that OMTech doesn't cover freeze damage.

Disclosure: some links on this page are affiliate links, and we earn a commission from OMTech on purchases made with our code or link. It costs you nothing extra.

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