Sand Pits in Opal

[mirkaba]

I was grinding a great seam opal this morning and got it rubbed down to exactly where I want it to be when, lo and behold...... pin point sand pits! About a half a dozen or so appeared and they are deep.  I mixed up a small batch of Colours grindable epoxy and pressed it into the holes . Then painted the surface over the pits. It will be dry enough to smooth down in about 24-48 hours. I don't deal with this problem too often but was wondering how you folks deal with similar problems. I have ground out and filled pretty large holes in opal with this stuff. Are there any other recipes out there? Thanks   Bob

[Taogem]

Bob, I am extremely interested in your process.

Here are a couple of recent  links to discussions here.

Opticon and pits filled with polish.

Opticon and initial oven temps

I was just in the rock shop today talking about this yet again. They kept coming back to the epoxy 320 and talked about the opticon of which I had no success.

[mirkaba]

Thanks George..............Overall I am pretty happy with the Colours epoxy. I heat the opal before I apply it. A very light heat as I have totaled a couple of really nice rocks by getting them too hot. I have a lightning ridge that I ground the sand out of and completely filled in the abcess and it turned out great. I have dead batteries or I would post a couple pics. The stone I am working on did what I was worrrying about and a small bubble came to the surface. This isn't a big thing but this is a pretty nice stone and I want to get the finish as good as possible. So I will just sand her off and try it again. I usually clean the stone with acetone before applying the epoxy. NOT fingernail polish but good old industrial acetone. (must be well ventillated) Also I use hypodermic syringes to mix the epoxy so the mixture is as close to exact as I can get it. I also have not had much luck with the opticon. Its probably just me though. I have even tried gap filling Hot Stuff...A total wash. I will get some pics up this evening and maybe we can keep the threads going and all learn something..... Bob

[Taogem]

Excellent.... Yes lets keep this one going.....

[Taogem]

Thanks George..............Overall I am pretty happy with the Colours epoxy. I heat the opal before I apply it. A very light heat as I have totaled a couple of really nice rocks by getting them too hot. I have a lightning ridge that I ground the sand out of and completely filled in the abcess and it turned out great.

Part of the Opticon process requires some heating in oven at about 150 deg for an hour or so... 

I did an internet search for "Colours grindable epoxy", but nothing came back. I would very much like to give this a whirl. Can you point me to where I might buy it?

[mirkaba]

It is sold by Rio Grande.....Bob

[seth]

Color epoxy works good. I am not a fan of opticon. The resin heated does bring depth to andamooka sanstone matrix and other grainy stones. I hate to fill any stone but sometimes you must. If I ever get time I will finish the work on my nano silica particle stabilizer.

[Taogem]

It is sold by Rio Grande.....Bob

Ok, I found it in my magazine Bob.

They really make it so a person can use it with a variety of minerals. A lot of different colors to choose from.

I mostly run into my pitting problems with agates. I don't know if that is as common for others, but has been the case for me.

I will take your advice and use the syringes. Then it looks like will need both the resin and hardener.

I also see a Colores finish powder. Apparently something to do with being absorbed by the wet surface, leaving a iridescent finish.

It says to try mixing the powder into the Colores color mixture for varied effects.

Have you tried this.

Seems like the Rio Grande has everything! I need to check it out more closely, page by page 

[freeform]

In my opinion, based on the avaiblity of good opal rough. I just wont work it if its needs to be stablized. In that case, if i cant make it into a doublet or triplet, it gets tossed.  What most people dont realize, is opal in general is not a good jewelry stone. Unless its the matrix types which are not pure opal. based on how naturally unstable they are, if they further reqiure stablizing, i personally get very uncomfortable in this case if the piece is being cut for jewelry, or a jeweler. It just wont last in a setting in most cases, at least longer than a couple years. As with most opal, you rarely if ever see heirloom opals.

"hot stuff" gapp filler(green bottle) is another option i would try out. Ive used it before on copper ore silicates and it worked good. Though i do prefer opticon, there is a high learning curve there.

[mirkaba]

Okay  I realize what you are saying Freeform. But I occaisionally find a great picture or story opal that is more often than not associated with some sand in the potch. I want to preserve the character of the stone and the pitting is so minor That I want to deal with it. Also the Lightning ridge stone seems to be quite a bit more stable and hard than other Australian varieties. I have committed to buying half a kilo of "good" rough in Sept.  So I have a couple of months to hoard my sheckles. Sorry about the photo....For some reason the camera focused on everything except the opal. The pittinf are the very small white spots in the upper center of the stone. I can get back to work on it now      Bob

[Taogem]

One of the members of my local gem and mineral club mentioned this Liquid Glass. Claims it works well.