Engraving Glass w/ CNC

[wildwestpat]

Hi Matt

If this is a one off and you don't want to go to the expense of diamond tooling can I suggest you try this:-

Build a dam around the part of the sheet to be engraved using strips of metal and sealing on the outside with plasticine / modeling clay. The dam will be used to hold the coolant and abrasive so it only need to be a 1/4" high. Make up a tool out of soft copper with a flat end and required diameter. Mix up carborundum grit with a mixture of olive oil and turpentine. The amount of carborundum to the olive oil turps mix should be visibly thickened by the addition of the abrasive but the aim is for it to be liquid with the grains in suspension. Start with a 50% mix olive oil to turps but you will have to do some experimenting on a bit of scrap glass of the type you are using. The grade of carborundum grit determines the degree of frosting.

Place sufficient abrasive mix within the dam over the point at which the first figure is to be cut. The mix should be thick enough to stay put on the glass without spreading over a wide area. When you plunge the cutter into the mix the puddle will rotate and a slow speed of 1000 rpm would be a starting point - raise when you have the pecking sorted. Use a lift shift and repeat step as in peck drilling to allow the abrasive to be replaced before the copper contacts the glass. Diamond dust or diamond lapping compound will also work.

I have used this method for cutting holes and making decorative spots on glass plate.

Hope this helps - Regards - Pat