I acquired a CO2 laser engraver with a Synrad 25W laser source. I was told it 'probably' needed re-gassed. I found the beam path to be grossly out of alignment and the mirrors were dirty. After a realignment and cleaning it appears to be functional. I don't think there is any issue with the laser source but I'd like to measure the power out. As it is, directly out of the source it will burn a spot on cardboard 6-10 feet away at 10% power, even at 5% in several seconds.

Try it on a concrete block at full power and see what happens after a minute or two.

I know where there is (or was) a melted spot about 1" in diameter in a concrete block wall because a graduate student (from China) turned on an infra-red laser when he shouldn't have.

How accurate do you need to be?


If reasonably accurate is sufficient, i think i would set up a beaker and a known weight of water.  Then boil water using the laser for a set time, weigh the remaining amount of water, and go from there.

This assumes efficient (100%) transfer of energy to the water, which assumes total beam absorption by the water.

I don't believe either assumption.

The issue is beginning at the output of the laser & measuring power then measuring after each of the 4 mirrors to determine the output of the laser and the loss at each mirror. So it has to be reasonably portable. There is a budget power measuring device that I found that might be an option. It's nothing more than a zero set oven thermometer with a wattage scale. It has an anodized aluminum block attached to the end and it is calibrated against some known standard. I'll look into the math related to raising the temp of a known mass of an alloy. aka calorimeter.

I use C02 laser cutters at work all the time - what are you using it for? We never calibrate or measure the power output and they have been chugging along reliably for years. Just make sure you keep the lens and mirrors clean and you'll be good to go.

It will be an addition to the shop for whatever application requires it.
The ability to cut acrylic will probably be its biggest application at first but who knows. I was wanting to evaluate it for power output before I find myself in a situation and have to rely on it. I recon I'll try some of the settings & materials from the chart and see how it performs. If it performs as spec'd then I'll call it good.

It has 25" on the X, 18" on the Y with pass thru doors for no Y limit and 6.5" on the Z I'm envisioning a number of potential projects.

I also have 50W fiber laser that I use for NFA & other engraving in the shop. It's limiting factor is the size of the marking field.