Tuesday, December 23, 2014

laser engraving stainless steel w/ plaster















So Bryan and I tried the airbrush and the plaster of paris particle size was too large to go through the air brush even after considerable thinning. I finally tried the solution with a cheap detail gun and it worked great. Bryan applied one coat and then used the heat gun to dry the piece rapidly. Then he applied a second coat and repeated the heat application with the heat gun. The resulting surface was quite even. We set up the Rhino file and finalized our settings using the afore mentioned settings. It worked like a charm! Check it out.

I believe this is working due to the chromium content of the stainless steel. Stainless has a passivation layer that is thin and completely transparent; Chromium oxide. When combined with calcium sulfate (plaster) along with the heat from the laser and potential water from the surrounding air, you end up with calcium oxide and chromium sulfate. Chromium sulfate creates the mark and the calcium oxide washes off. Again this is my basic premise and understanding of what’s occurring here. 

 If you slow the laser down, it will create a darker etch/mark. Higher wattage lasers should be able to reduce the power a bit from my 100% power setting on the Epilog Zing 40 watt.





7 comments:

Shop Teacher Bob said...

The quality and the diversity of the work you and your students are turning out never ceases to amaze me. My students make scrap metal. While that's not as bad as it sounds, they are after all beginning welding students, it's just not quite the same. Necessary? Absolutely. Exciting? Not so much.

Keep up the good work. Your an inspiration not only to your students but to an old "Shop Teacher" as well.

Best wishes for the holidays and enjoy the time with your family.

Frankie Flood said...

Thanks! Likewise, I always love to read about your work. I can't wait to see what happens with the FB or the BSA if you decide to do a new build when the Sportster is fully sorted and on the road.

Happy Holidays to You and your family!

Joel Hall 2007 said...

This looks great! How does the mark and chemical process compare to a commercial option like Cermark?

pooua said...

How likely is the etching to rust?

Frankie Flood said...

I'm not sure; we haven't tested that. I give it a shot though...

Frankie Flood said...

Joel Hall 2007, I think it's a great match to Cermark as long as the application of the plaster is even and not lumpy.

J. Siefer said...

I tried Moly Lube, and didn't get that great of results. When I tried this, kind of the same thing. It took a small bite into the metal, but nothing mind-blowing. In fact, I actually got pretty amazing results with my 80 watt at full power, and nothing else. I'd be interested to try Cermark- if it wasn't for the pricetag.

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