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Jeff White

How to age a pearl eye?

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 Just replace this eye in the frog and realized when I was all done, that it looks terrible in comparison to the other side, which is probably 100 years old.  Actually, I’m probably gonna have to replace the other side as it’s pretty cracked and messed up but regardless, it still looks way too new. Hopefully this wasn’t something I should’ve done before I put it in. Didn’t think this one through very carefully.......

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The different appearance of the two eyes could be because they come from the shells of different mollusk species rather than because they are different ages.

Sometimes etching the surface of the pearl with acid can give an aged appearance by lowering the surface and making it a little uneven, but I don't know if acid can change the color.  I have used vinegar and nitric acid.

I have a collection of old pearl eyes that I have salvaged from junk frogs.  When I need to replace an eye, I can usually find one in the collection that is the right size, color and appearance, and it will also already have a concave face.

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Thanks Brad.  I thought I had heard something like that in the past.  It's not just the color, but the smoothness of a new pearl that really seems....wrong.  Can I source a form of Nitric acid from something other than a chem supplier?  Like....a pool acid?  Anyone know?    

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I imagine it’s mostly calcium carbonate and acid will eat it away. Try diluted vinegar and proceed very cautiously.  I would experiment first on blanks. 
 

Also, try just dirtying it up with some pigment and even linseed oil rubbed into its pores.

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I too have  a box of old eyes, and can usually  find one to  work  with  a  little  fitting.

Whatever  I  do,  first I clean the frog and wash out the old glue. Then I mask the frog  with a piece of shoulder  tape material, with a hole cut in it the size of the eye. I can file, sand, and etch the pearl without touching  the  ebony. 

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1 hour ago, Conor Russell said:

I too have  a box of old eyes, and can usually  find one to  work  with  a  little  fitting.

Whatever  I  do,  first I clean the frog and wash out the old glue. Then I mask the frog  with a piece of shoulder  tape material, with a hole cut in it the size of the eye. I can file, sand, and etch the pearl without touching  the  ebony. 

Yup, that's what I did, however, what is shoulder tape?  Is that the tape athletes use?

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7 hours ago, Jeff White said:

...Can I source a form of Nitric acid from something other than a chem supplier?  Like....a pool acid?  Anyone know?    

I don't know where to get nitric acid.

in a discussion on this same topic on this forum a few years back the following acids were suggested for treating frog pearl eyes:  vinegar, lemon juice, muriatic acid (from a pool supply or masonry supply seller).

 

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8 hours ago, Jeff White said:

Thanks Brad.  I thought I had heard something like that in the past.  It's not just the color, but the smoothness of a new pearl that really seems....wrong.  Can I source a form of Nitric acid from something other than a chem supplier?  Like....a pool acid?  Anyone know?    

First, please apply the brakes and slow down:huh:

Pearl is something called "nacre", which is a composite of aragonite (a particular crystal form of calcium carbonate, different from the more common calcite) and a protein called conchiolin.  Being calcium carbonate, any common acid will attack it and cause bubbles of CO2.  Vinegar or lemon juice would be more than adequate to rough up the surface.  Neutralize it with baking soda afterwards.  Any of the stronger stuff you mentioned is gross overkill.   :)                  

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4 hours ago, Conor Russell said:

I too have  a box of old eyes, and can usually  find one to  work  with  a  little  fitting.

Whatever  I  do,  first I clean the frog and wash out the old glue. Then I mask the frog  with a piece of shoulder  tape material, with a hole cut in it the size of the eye. I can file, sand, and etch the pearl without touching  the  ebony. 

Is there a way you can provide a picture of this process? I am having trouble imagining.  What is shoulder tape?

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4 hours ago, Conor Russell said:

I too have  a box of old eyes, and can usually  find one to  work  with  a  little  fitting.

Whatever  I  do,  first I clean the frog and wash out the old glue. Then I mask the frog  with a piece of shoulder  tape material, with a hole cut in it the size of the eye. I can file, sand, and etch the pearl without touching  the  ebony. 

I watched Paul Siefried replace a pearl eye once. He applied thick CA to the frog and used that as the barrier instead of tape, then cleaned the CA off after finishing the eye. I also watched him use a drop of Nitric Acid to bring the pearl below the surface of the ebony, placing a drop with a coffee stirrer.

Nitric is dangerous. 

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7 hours ago, Dave Slight said:

I think the shoulder tape Connor referred to is the clear self adhesive tape, used by some to protect the upper rib (shoulder) from varnish wear.

Ohhh, I was thinking of MY shoulder.  Makes sense.  

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16 hours ago, Violadamore said:

First, please apply the brakes and slow down:huh:

Pearl is something called "nacre", which is a composite of aragonite (a particular crystal form of calcium carbonate, different from the more common calcite) and a protein called conchiolin.  Being calcium carbonate, any common acid will attack it and cause bubbles of CO2.  Vinegar or lemon juice would be more than adequate to rough up the surface.  Neutralize it with baking soda afterwards.  Any of the stronger stuff you mentioned is gross overkill.   :)                  

Wow, that's some info. Thanks.  However, I tried the vinegar (full strenth)and it did nothing.  Let it sit....nothing.  Of course, after doing this on Sat afternoon ( and cleaning it off)and seeing myself return Tue AM to find no pearl left............................  Maybe I'll try the Lemon juice next?  Then, acid if no luck.  I had to make a new pearl for the other side and a new slide too.  All 3 make it look like a new frog....and at odds with the stick.

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1 hour ago, Jeff White said:

...I tried the vinegar (full strenth)and it did nothing...

Perhaps vinegar comes in different strengths, because it did something when I tried it on the eyes of a frog that I made.  When I put the vinegar on the eyes were perfectly flush with the ebony.  After half an hour the pearl was eaten away enough that I could detect a slight surface discontinuity when I ran a fingernail across the pearl/ebony boundaries.

I've never tried lemon juice.  When I put nitric acid on pearl there is a visible bubbling reaction as the acid attacks.  But this is very nasty stuff.  It scares me and I hate using it.

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When people on this forum think ‘acid’, why do they always go for nitric? That’s surely the nastiest option unless the aim is to colour wood. If it’s just to react with calcium carbonate then any acid will do the trick. If you want something stronger than vinegar, then hydrochloric acid - known as ‘spirits of salts’ - will work. It should be available in any hardware shop. You will probably want to dilute it considerably. Always add acid to water, not water to acid. I use it to clean my toilets.

Andrew

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Ok, well, it seems maybe I need to leave it on longer.  I'll try leaving the vinegar on longer, or get into some "light duty" acid.  Do I still have window pane in my freezer?????

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1 hour ago, Jeff White said:

Ok, well, it seems maybe I need to leave it on longer.  I'll try leaving the vinegar on longer, or get into some "light duty" acid.  Do I still have window pane in my freezer?????

Very dilute hydrochloric acid is used for field testing carbonate minerals.  Vinegar is successfully used for cleaning carbonate scale out of coffee makers and toilets. Lemon, lime, and pineapple juices are used as metal etchants in Southeast Asia (as well as in my keris restorations).  Nitric (as I have ranted about here in the past on several occasions) is best reserved for etching metal and producing explosives in competent hands.  Sulfuric (battery acid is a dilute form) is another powerful acid best used with caution.  Either nitric or sulfuric can cause wood to degenerate, as well as produce serious burns. 

Is it possible that someone has slipped you a laminated pearl product intended for jewelry, and you are trying to etch plastic?  :huh:

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3 hours ago, Violadamore said:

 

Is it possible that someone has slipped you a laminated pearl product intended for jewelry, and you are trying to etch plastic?  :huh:

No, it powders up just like pearl.  Ill be more patient with the vinegar

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We use Nitric on already wet pearl...this gives a nice etch without accentuating the stress marks you can get with some pearl.  The key to putting in pearl eyes and not damaging the frog is to fit the pearl eye before gluing......completely, then glue with hot glue.  It is real difficult to damage a frog when there are no tools close to it......using CA as was mentioned will leave a white line in the joint after cleaning, and if you are lucky enough to remove the white line, you end up with a shiny ring surrounding the eye.  Tape will leave the eye slightly above the surface when you are looking to get an eye appropriately below the surface (before acid).

...finger eyes should be slightly lower than thumb eyes for those with an OCD advantage.....

 

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1 hour ago, Jerry Pasewicz said:

..fit the pearl eye before gluing...

I assume this would require repeatedly putting the eye in the hole in the frog to check the fit and the concavity then taking it out to adjust it.  But whenever I try to put an eye in a hole and take it out:  1.  If the eye is too big I can't get it in the hole, of course;  2.  If the eye fits closely the way I would like, it's almost impossible to get it out; and  3.  If the eye is small enough to remove it easily, the fit is too loose.

So how do you fit the eye before gluing it?  Specifically, if the eye is the right size for a good tight fit, how do you get it out to work on the concavity?  And once you get it out, do you file it to make it concave?  If yes, how do you hold it while filing it?

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1 hour ago, Jerry Pasewicz said:

We use Nitric on already wet pearl...this gives a nice etch without accentuating the stress marks you can get with some pearl.  The key to putting in pearl eyes and not damaging the frog is to fit the pearl eye before gluing......completely, then glue with hot glue.  It is real difficult to damage a frog when there are no tools close to it......using CA as was mentioned will leave a white line in the joint after cleaning, and if you are lucky enough to remove the white line, you end up with a shiny ring surrounding the eye.  Tape will leave the eye slightly above the surface when you are looking to get an eye appropriately below the surface (before acid).

...finger eyes should be slightly lower than thumb eyes for those with an OCD advantage.....

 

Happy New Year Jerry!

When you say "fit " do you mean matching the the concavity of the side of the frog and the lense shaped concavity of an old eye as well? how do you hold on to the little buggers while doing this? like wise are you doing the acid etch before or after installation?

Whoops! looks like Brad types faster than me.

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20 hours ago, Brad Dorsey said:

I assume this would require repeatedly putting the eye in the hole in the frog to check the fit and the concavity then taking it out to adjust it.  But whenever I try to put an eye in a hole and take it out:  1.  If the eye is too big I can't get it in the hole, of course;  2.  If the eye fits closely the way I would like, it's almost impossible to get it out; and  3.  If the eye is small enough to remove it easily, the fit is too loose.

So how do you fit the eye before gluing it?  Specifically, if the eye is the right size for a good tight fit, how do you get it out to work on the concavity?  And once you get it out, do you file it to make it concave?  If yes, how do you hold it while filing it?

The eyes on bows are cut with basically a spade bit.  Many times when the old eye is cleaned out, you will notice the pilot hole goes into the mortise.  For these cases I have a dental tool I have ground and shaped like a hockey stick. I can put that into the mortise and punch out the eye from the inside.  For tough eyes that do not have a hole, I have a couple different strengths of double sided mounting tape that get put onto different diameter drill rods.....I use the strength of tape that is appropriate....if it does not work I kick it up a notch.

For shaping the concavity,  I have a short (4”?) piece of 2” diameter PVC that I have heated and bent to be egg shaped instead of round.  I also will use glasses, cups, cans, or any appropriate radius.  Then, I mark the eye on the inside face with a sharpie which edge is the rail side, and while holding a piece of 600 on the radius object with my left hand, I index the the eye against my right middle finger and sand moving up and down to the desired radius......only radius. Once the radius is set, I mark my  rail side edge on the radius side and take to thickness on the flat side of the eye.

Happy New Year to you Nate.  I do not mind putting on the acid after it is glued, especially because the eye is already below the surface so the drop you put on does not need to span the entire eye.  Obviously doing the acid before gluing is safer if one is not confident in their dropping skills........

Also, eyes do not need to be tight.  When replacing an eye, it is rare that the edge of the hole is still sharp and not at least a little rounded over.....making the eye slightly under the surface to coincide with this wear eliminates the need for a tight fit, and making the eye incredibly tight up to the surface will never make the eye look like a good fit.  When the edge is sharp, it is likely a new bow with an eye that fell out... the maker of the bow made really tight eyes then glued them by putting thin CA over the top starving the joint.......hide glue prevents this as you put the glue in first which allows positioning.

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