Making an Ammolite Pendant - part 1

I'd mentioned in an earlier post that ALL Ammolite MUST be either clear epoxy coated capped with clear quartz glass to protect the thin, soft, easily flaked aragonite sheets of color.
Here is how I make epoxy coated Ammolite doublets.

1.  Spend an inordinate amount of time looking at the piece of Ammolite rough you have selected to work on.  Look and look some more - savor the potential the piece has.  Have a cup of coffee, take a walk, dig in the garden, look at the selected piece some more.........  and then some more.........

2a.  Select one of your awesome pieces with a natural backing of about 2-4mm of the host gray shale and carefully sand the top face to remove any shale stuck to it.  This is definitely the type of work where the old lapidary adage "grind a little and look a lot" is the way to go.  Even more awesome now?  Good.  Carefully grind the outside shape of the stone and polish the top face up to 14,000 mesh diamond.  Your ready to coat your finished stone.

or

2b.  Select one of the thin flakes you have, which may be double sided, and try to decide which might be the top.  Repeat step 1 with this one piece only.........

3.  Carefully - very carefully - sand the top and bottom surfaces with a 320 or finer Nova wheel using lots of water.  Take your time - you are going at it too aggressively....... I know..... especially if you are used to doing lapidary work with agates, jaspers, and the like.  Do not grind the edges in an attempt to shape the piece in any way.

4.  OK.... if the flake of Ammolite you are working with is double sided, the inevitable problem now is - both sides of the flake are awesome!  Now what do I do?  Repeat step 1, of course.  One side is going to have to be sacrificed and glued to backing.  I use black jade.

5.  Sand the bottom side as nearly flat as you dare on a flat lap.  A lot of Ammolite, most I think, undulates somewhat so a thin flake may not be capable of being ground dead flat - don't worry about it.  Stop when you are too worried to go further.

6.  Select a piece of backing (black jade) 2-4mm thick.  It does not have to be polished.  In fact a rough surface is better for the epoxy to adhere to.  Mix a small amount of two part epoxy ( I use Hughes 330) and color it black with lamp black powder (traditional and messy) or color it the way I was taught by Joe DiPetro - use a couple of very small drops of real India ink from an art supply store.  Coat the stone thinly with the epoxy and drop the Ammolite flake onto the backing by placing the edge of the flake onto the backing at a 45 degree angle and  letting go of the stone so it drops down like closing a book.  This pushes out the air and minimizing getting air trapped between the Ammolite and the backing.  Move the flake around with a finger tip or the erasure on the end of a pencil.  Apply a little pressure, but not too much.  The flake will slip around easily at first, but as the glue layer is squeezed thinner it begins to act stickier and the flake will become more difficult to move.  Be sure the stone is level while it cures.  Epoxy, when first mixed is fairly thick, but actually gets thinner for a period of time due to the chemical reaction going on, before it hardens.  If the stone is not level the flake will slide right off the backing when your not looking.  Check it after about 10 minutes to be sure it has not moved.  Let it cure for at least a day.

Glued and cured.  Note the rough saw cut finish on the black jade backing

The flake is less than 0.5mm thick.  The backing is about 3mm thick

7.  Cut the excess backing away using a diamond blade trim saw.  Cut close to the Ammolite but leave a little margin to grind off.

Close but not too close

Trimmed and ready to grind

8.  Grind the black jade backing to the edge of the Ammolite.  Carefully shape the stone to your liking.

9.  Polish the top face up to 14,000 mesh diamond.

10.  Sand the bottom edge of the backing to remove the sharp edge

11.  Glue a small dowel to the bottom using a small drop of thick or gel type super glue.

Note the final outside shape and the rounded bottom edge

12.  Cover a piece of styrofoam block with plastic wrap and stick the dopped stone into the block.  Make sure the stone is even and level - never mind about the stick - the stone MUST be level! Clean the top and edges of the stone with a cotton swab dipped in acetone or alcohol.  All oil, including finger oil, needs to be removed.

13.  Mix a small amount of clear two part epoxy.  I use Hughes 330.  I use small pieces of thick flexible plastic and a toothpick to mix the glue.  Mix carefully, but bubbles are inevitable.  Most are the result of out-gassing from the chemical reaction taking place, not from your mixing air into the glue - but do mix slowly and thoroughly so you don't mix a lot of air into the glue.  Don't worry - the bubbles will be eliminated later.

Use equal amounts of the 2 parts

Lots of bubbles!!  No sweat......

14.  Let the mixed epoxy sit for a couple of minutes.  See - fewer bubbles already.  Pour the epoxy off the small piece of plastic and use a disposable kid's craft brush (I buy them in bulk from the craft supply store - real cheap) to scrap the glue off the plastic and on to the stone.  Use the brush to encourage the glue to flow evenly over the stone and down the edges.  Paint the edges with the brush to ensure the edges are coated with epoxy.

A bazillion small bubbles.... no big deal!

15.  Ahhh..... the secret to epoxy bubble elimination!!

A Butane pencil torch!

16.  After applying the epoxy to the stone, occasionally dab the edges with the brush, pick up drips on the base with the brush and let them drip onto the stone in spots that need a bit more glue, and use the brush to remove hanging drips from the bottom edge of the stone.  Spend a few minutes on this touch-up and clean-up work.  Then comes the torch!  With the torch lit and on a low flame, gently play the torch over the surface of the epoxy from a distance of about 6 inches to a foot away.  THE BUBBLES WILL DISAPPEAR!!!  You will be dumbstruck (gob smacked, if your British) the first time you see this.  It's amazing.  Do not have the torch too close to the epoxy surface.  Every torch is different.  To judge the correct distance, place your hand in front of and far away from the flame, move the flame back and forth and move your hand closer until it just feels warm.  Go ahead - it's just a little pencil torch.... not some honking bonfire.  The distance will be about 6 to 12 inches.  You may have to continue to do touch-up and drip clean-up with the brush every couple of minutes and you may need to repeat the torch trick.  

You can't see the flame, but it is only about a 1/2"" long and is about 5-6 inches from the stone

OK - a little explanation about the bubble bursting.  It's more  chemistry stuff.  It is not the heat from the torch that does the trick.  It is a chemical reaction between the combustion gases from the torch and the epoxy that bursts the bubbles.  It's mainly carbon monoxide and carbon dioxide that does it.  In fact, you can perform this miracle without a torch by exhaling strongly with an open mouth onto the epoxy (not blowing with pursed lips).  The carbon dioxide in your exhaled breath will work, but it takes much more huffing and puffing.  Ok for one stone, but if you have a group to do you'll probably keel over trying to get rid of all the bubbles.  Get a torch.

Clean and clear epoxy coat.

Let the epoxy cure at least one day.  Three is best.

Part 2 next time.