Safety question about galvanized steel plate

Is it safe to use a piece of galvanized steel plate 12x12 inches as a shield. Not to try and burn or cut but to use as a shield in the bottom of my K40.
I have cut a hole so that my rotary will fit inside my K40, well that leaves a hole that now when lasering other stuff like just wood etc on the normal bed I have the beam has been burning the table beneath this hole, so I am trying to think of an easy way to block the hole when not using the rotary.

I read somewhere that a CO2 lasers and galvanized metal don’t go well together due to gasses emitted.

Hot-dip galvanization - Wikipedia

In long-term, continuous exposure, the recommended maximum temperature for hot-dip galvanized steel is 200 °C (392 °F) […]

Hmm. I expected that temperature to be quite a bit higher. 200 °C max is kinda crap.

Well, the beam is extremely defocused, most of it is reflected, and this piece of sheet metal is essentially a large heat sink. It’s probably fine.

But I’d prefer to use something else. E.g. aluminium, stainless, or some old baking tray (without non-stick coating).

Your local hardware store might have some sheet metal. The super thin stuff is usually pretty cheap.

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Yea I already checked Lowes here locally and all they have is either galvanized or hot dipped galvanized.
I do have some old baking sheets I could probably cut up to the size I need. Was just going to go with an aluminum or stainless sheet but they are both kind of pricy at the moment on amazon for a simple 12x12 inch piece.
And although the beam is pretty defocused at that range it sure did leave some nasty burn marks on the table below the chassis where I cut out the hole.

Guess I will play it safe and just order aluminum or stainless from amazon.
Thanks for the feedback!

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Aluminum foil perhaps? It won’t cut it at that distance…


I ordered some thick foil tape that I am going to use on my motorized labjack I designed, I will probably cover it with that for now.
K40 Laser Motorized Lab Jack - YouTube


I don’t see a problem using galvanized metal in the bottom of the laser bed. As mentioned before, the beam is going to be very defocused by the time it the plate. I have aluminized duct tape covering a hole in the bottom of my laser and it works just fine.


If you want aluminum, go to a local metal yard. It will be way less than what you pay online and cheaper than Home Depot or Lowes. I buy off-cuts for $3.50 per pound from a metal yard conveniently located not far off the freeway along my commute to and from work.

For example, a 12"x12" piece of 1/8" aluminum at a popular online metal seller would be $30.62 plus shipping. It would cost me about $6.20 at the metal yard. It is actually cheaper for me to make parts out of aluminum off-cuts than from plastics. When I was cutting new plates to modify my CNC router, I found a 4 foot by 12" piece of 1/4" aluminum plate “off-cut” and paid about $50 for it. For protecting the work top from a laser you could get a much thinner and therefore much cheaper piece.