View Full Version : Rotary for pearl shell?

John Noell
04-11-2010, 3:04 PM
I am curious about the possibility of using a rotary to carve pearl shell. I can put a light engraving on the shells with my laser but I'd like to be able to engrave deeply (e.g., 1-5mm). The shells are not flat. Is there anyting out there that can "float" a bit to compensate for the slightly uneven surface but still engrave to some depth? Suggestions welcomed!

John Noell
04-12-2010, 2:46 PM
Does anyone have experience with anything like the Gravograph IM4? Would that do designs in shell?

Ray Uebner
04-13-2010, 3:35 AM
I have a signature 8080 plus that does just that and it applies the same pressure on the uneven surface. That is the best I can do for you. You could laser at a slower speed and several passes that also might work.

John Noell
04-13-2010, 2:56 PM
Thanks Ray. Due to the nature of the shell, additional passes with the laser don't do much except turn a larger area powdery white. The first pass affects the shell much like glass - causing microfractures. (And the same techniques, such as wet paper, help similarly.) I will be Googling the 8080!

Mike Null
04-14-2010, 9:41 AM
My Newing Hall 350 will do that as well as will other models of the N-H.

John Noell
04-14-2010, 11:35 PM
Being completely ignorant about rotaries, is it common that they can engrave on uneven surfaces? How can you control the depth of the engraving when the surface is uneven? Where is a good place to learn more? (Living on a remote island has it drawbacks.)

Niklas Bjornestal
04-15-2010, 1:34 PM
Where is a good place to learn more? Google :p
(Living on a remote island has it drawbacks.)Google works well on most islands to :rolleyes:

John Noell
04-15-2010, 2:19 PM
Yep - Google is great and I have been teaching search engine use for many years (anyone remember "Dialog"?). However, if you try Googling (as I have) for specific information on using small CNC machines for uneven surfaces on shell substrates you will soon learn why I seek information via this forum.

Mike Null
04-15-2010, 2:24 PM
Not all rotary machines can engrave on uneven surfaces, but you may be able to use a nosecone to regulate depth. In the case of N-H the device is powered by air so you can regulate the air pressure to regulate depth or ue a couple of other ways.