Hi there, I recently bought the H2D 40w laser combo, I’m completely new to laser cutting but willing to learn. Is there any useful tips to keep in mind when using the laser?
Like glass engraving, do I need marking spray to get a good result?
If I were to engrave heavy steel objects like a 3lb axe head when the mesh engraving comes out is there anything I’d need to know about that?
Any advise is welcome, but have a little mercy on me for my ignorance, I don’t feel in the mood to melt my machine by doing something worng 
Since the H2D is a blue diode laser (around 450 nm wavelength), there are a few things worth keeping in mind:
- Glass engraving
A blue diode doesn’t engrave glass directly since the wavelength passes through or reflects instead of being absorbed. You’ll need a marking spray or a coating (like black paint or a dedicated laser marking compound). The laser then burns the coating and leaves a visible pattern on the glass. - Steel and heavy metals
A diode laser cannot engrave steel directly like a fiber laser can. At best, you can mark the surface using a marking spray or by applying a coating. Trying to cut or deeply engrave an axe head or similar hardened steel won’t work – the laser won’t remove material, it can only discolor or mark a prepared surface. - Heat and machine safety
The diode isn’t powerful enough to melt big chunks of steel, so you won’t damage the machine that way. The real risk is from reflections: polished metals reflect the laser beam unpredictably, which can be dangerous both for your eyes and for the machine optics. Always mask or coat reflective surfaces before attempting anything. - Learning curve
Focus on materials the H2D is good at: wood, plywood, leather, paper, cardboard, acrylic (not clear), painted or coated metals, and some plastics. Start with flat, non-reflective, non-transparent materials to build confidence before experimenting with marking sprays and more advanced projects.
So in short:
Use marking spray or coatings for glass and metal.
Don’t expect to engrave steel directly – only mark it.
Avoid shiny bare metal surfaces without coating.
Start with easier materials like wood or leather before moving to trickier ones.
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L0rdS474n is correct. But, another thing to watch out for is make sure you are using laser safe materials. There are guides online. One very big no no is PVC! It will release chlorine gas when lasered and not only is it very toxic, it is also not good for your machine.
I would be very careful about weight of things being etched as it has to sit on the printer bed.
Oh yikes, thanks, I’ll put that on the no-go list.
I was thinking the same thing, can’t be good for the z-screws. 3lb is a bit on the extreme size for something I’d do, 1 or 1 1/2 is about max I’d do for steel marking.
There are certain materials that release toxic and carcinogenic gases when burned. Whenever I need to process such materials, I rely on my Carvera Air to handle the task. Some gases have a noticeable odor, but many pose a hidden danger without any smell at all.
As an additional precaution, I avoid using the Bambu Lab safety glasses. Their level of protection is only claimed, not certified or stamped. Instead, I use laser goggles from Thorlabs, model LG18C.
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There are many materials that release toxic and carcinogenetic gases when burned.
The biggest no-no is PVC. As mentioned, it cooks off Chlorine gas which combines with moisture in the air (or your lungs) to produce Hydrochloric Acid. Bad to breath, bad for the machine.
But even relatively innocuous material can be bad. MDF for example, or plywood, could be using glues that produce gasses like Formaldehyde when lazed.
There are many, many websites that talk about materials you can or cannot safely put in a laser cutter. If laser cutting is new to you, you should read up on the materials you want to use before you use your machine.
And yeah, this diode laser won’t cut metal (as well as many other materials). But it will etch Anodized Aluminum.
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You’re absolutely right — plenty of materials release downright toxic gases when lasered, from PVC’s chlorine soup to the formaldehyde cocktail in MDF and plywood. Definitely not something you want in your lungs or on your machine.
And just for the record: I cranked my 40 W diode to 100 % on bare aluminum, and it didn’t even leave a scratch. 
Interesting, what brand/kind of marking spray would you recommend? Do some work better than others?
It won’t. But the laser will easily remove anodization exposing the base Aluminum again (which immediately oxidizes and turns white). You get something that looks like this:
You can buy blank anodized Aluminum stock on-line. Many shapes, sizes, thicknesses and colors. I have a stack of blanks that are business card sized, and some that are like dog tags (both military and the pet style).
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I have plenty of bottle openers made from anodized aluminum, but I used pure aluminum as a test to show others that it won’t even leave a scratch.
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The bird’s eye cam is not at all precise. What you see is not at all what you get and it should not be used to locate etching onto small parts.
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The left edge of the laser plate is ~14 mm offset from the actual leftmost cutting/etching area reached by the laser. To get a real idea of what your working area is vs the actual edges of the plate, I made a laser line rectange of 310mm X 250mm and placed a blank sheet of plywood on the build surface to see the real difference. The top edge is almost exactly aligned between the working area and the actual top edge where you can place material.
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When I saw my offset is more like 14mm, I cut a blank of 14mmX250mm and I shim that in on the left side of my new work so that the left edge of the new material now matches the left edge of the workspace for the 40w laser.
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To reliably get your work positioned for etching things like the keytags, make a laser cut that matches the dimensions of your work, and cut that permiter out of a sacrifical piece of wood that is reliably placed on the workbed to match 0,0. now replace the cut out section of the wood with your work piece, and substitute the cutting line with your etching job in the same location and you’ll get a more reliable result.
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