Making Chip Inlays

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From the SRP forum thread titled How to do Chip Inlays by icedog[1]

How to do Chip Inlays; The Icedog Method[edit | edit source]

Hey kids! Last month I posted this thread: New Scales on One of My Knives showing a knife from my collection I had customized. In that thread I promised to teach how I did the turquoise inlays on the custom scales I fashioned. Over the past twenty years I have developed and proven this method for putting inlays in substrates of wood, hard plastics, bone, horn, even metals. I have taught the process to several artists who have used it with fantabulous results. One furniture maker has made some pretty fancy pieces and some equally fancy cash on the sales of those pieces he inlayed using my technique. I hope some of you will try this method on projects of your own. While the results appear difficult and expensive, you may be surprised to find the process remarkably simple and gratifying.

Substrate Materials[edit | edit source]

Once you see the “big picture” you will understand why my method is suitable to produce inlays of any shape, color or size from very simple to ornate and detailed in the surface of practically any rigid material. You are limited only by your imagination and the laws of physics. As I did on the knife discussed in the above referenced thread, for this lesson I will be demonstrating on a piece of spalted apple wood:
Making Chip Inlays (1).jpg

Apple wood is typically bone white with deep brown heart wood. The grain is very tight and the wood when dry is rock hard. This particular bit of wood is highly figured because of “spalting” which is the fungal spores reacting with the sugars in the tree’s sap as they spread through the grain lines, eating the wood. Ya just gotta admire the power of nature and her ability to produce striking beauty even as she causes the destruction of a material as it rots away. You can find spalting in all types of wood but I believe the spalted wood of fruit trees is the prettiest because of the high sugar content in the saps. Happy spores are pretty spores! But this article isn’t about spalted wood. In the photo notice this wood is also “wormy”. It is those worm holes I will be inlaying. If I wanted to create my own design I would cut recesses to be inlayed with carving gouges or an electric rotary (Dremel) type machine.
Making Chip Inlays (2).jpg

This is a small sample of the vast array of burrs and end mills available to use for this process. Once you have designed your project you will easily decide which bit will best suit your purpose.

Inlay Materials[edit | edit source]

Making Chip Inlays (3).jpg

This is scrap turquoise. The operative word here is SCRAP.Notice the variety shapes finishes, colors and sizes of the turquoise chips. Anyone who is designing and fabricating projects utilizing turquoise will be generating scrap. Again look at the photo. There are pieces that were finished cabochons that broke during installation. There are also bits that are cut offs from much larger stones. Observe too the varied patterns and colors of the impurities (known as “matrix”) in the stones. This works to our advantage because it is yet another complexity that causes some stuff to be scrapped. While you can go to jeweler’s supply houses like Sleeping Beauty or Rio Grande and pay exorbitant prices for very nice materials, it is much more fun and frugal to shop around by walking into the studios of artists who are using quantities of turquoise, especially in the American southwest.
While on a business trip to Albuquerque, New Mexico I walked into the shop of a very prolific producer of silver and turquoise jewelry. When asked if he had any bits of scrap left over from his processes, he led me to a standard size three drawer horizontal file cabinet. He showed me all three drawers neatly packed full of bags of the very chips you see in the photo. I left the shop with ten pounds of turquoise in five zip-lock bags in exchange for a twenty dollar bill!
I will talk about other suitable materials a little later but first I want you to understand my process.

The Process[edit | edit source]

I am going to fill the worm holes with a blended paste of epoxy and turquoise so I the chips you see above are clearly too big. It is an easy task to pulverize turquoise into any size from smaller chips down to fine dust.
Making Chip Inlays (4).jpg
This is actually “shake” I separated from the bigger stuff by using a kitchen sieve. However you can crush turquoise by putting it between two sheets of steel (even large handsaw blades) and pounding with a hammer or you can quickly do it with an electric burr type coffee mill or spice grinder. I have a small Cuisinart food processor that I use for the job. As the blade is shot for anything but pulverization and the inside of the bowl has been severely stone blasted, it can never be used again for its original intended purpose (in sincere hopes to maintain domestic harmony I keep it well hidden from my girlfriend Scarlett, the machine’s original owner). Some projects (which I will show you in a little while) will use a combination of small and large chips. But in this lesson we are using what I’ve already showed you. We will be mixing it into a stiff paste with epoxy.
Making Chip Inlays (5).jpg
I use this Devcon High Strength 5 Minute Epoxy. I have a long history of work in both aerospace and the medical device industries. I have tested my process with every epoxy I have come across and (fortunately) none exhibited better results than this stuff you see right here. The goals for this application are three:

  • The cured epoxy must be hard and rigid so it can be polished.
  • It should be colorless.
  • It should bond to wood.

NOTE: If the epoxy does not adhere to the material into which you are putting an inlay be certain to undercut the recess you make to ensure positive mechanical retention of your inlay.

Be sure to have your substrate ready to receive the inlay before mixing the epoxy. The stuff doesn’t cure instantaneously but you don’t have all day either! Once the glue kicks you can do no more with it.

I always set the mixing cup, stick and leftover mix aside as a “witness sample”. What this means is that I use the leftover portion as an indicator to let me know when the inlay material is cured enough to begin sanding.

So here’s the inlay sanded flush with 100 grit sandpaper. It took about three minutes. I won’t go through the rest of the sanding but you should know the progression. I start with 100 unless I am using larger stones then I’ll start with 80 grit. The full progression will be 80, 100, 120, 150, 180, 220, 320, 400, and 600 and so on until you can polish with a wheel.
Making Chip Inlays (10).jpg

Alternative Materials[edit | edit source]

I mentioned earlier that the inlay material can be something other than turquoise. If it can be ground into dust or fractured or crushed or pulverized and mixed into a paste with epoxy, it can likely be used to fill inlays. Think about exotic hardwoods like ebony, purple heart, cocobolo, yellow heart, etc.

Conclusion & Contact Info[edit | edit source]

I hope I have put out enough info to interest and inform you folks. Any questions? I will always try to help you succeed.
Have fun,

Join in the forum discussion about this topic here or contact Brad by using the in-forum messaging options.

References[edit | edit source]