How to decide on applying epoxies/super glue or opticon as a possible option

[Taogem]

Thought might just start off with a few cabs I have to use.. I will start off, and hopefully others can add some examples that they have come across. Then for what ever reason we either decided to, or not to consider sealers as an option and why.

This first cab is likely going to get scraped or at least trimmed a whole lot due to the one crack upper left..

The area I wanted to share as an example is the very small vug, and the long gap where the agate and lace material meet. It is not a crack or fracture.. Presently it has a bit of polish in there.. I will give that a go around with the sonic cleaner prior to applying the epoxy.

For me, this would be a candidate for filling. Because the stone consists of a lot of agate, once filled it will blend nicely and look like a natural agate filled fracture. Although a good candidate, for me it is borderline.. If it were not for the other crack I might well be ok with the natural appearance and don't feel overall that it makes the stone unusable or unsellable. Same with the small vug. I would leave it be too..



This agate has a crack. Actually similar as it is where the Marcisite and agate meet. In this case it can not be repaired.. joint/crack is just too tight to even consider getting any sealer into.

So I am going to just whack the end off considerable and go with a completely different shaped stone. Freeform ! Gotta love it !



This next Plume was plagued with pitting. The one thing I have noticed with the two part epoxy 330 is that when used on a clear agatized area, the epoxy just stands out like a soar thumb. Maybe someone can share a better experience with Opticon or Superglue, but the 330 has proven for me to be a unusable option on a clear agate area like this.



I am going to fill the area on the lace agate and show the results before I scrap it. Hopefully it will turn out with the agate filled appearance I expect.

These are just a couple of examples to talk about. I will add more as they arise. Hopefully others can share some other comparisons of dealing with pitting, fractures, etc, and best use of sealers for different problem areas.

[bobby1]

I find that if a fracture has any color such as rust or black it won't do any good to use Opticon. I reshape the cab to exclude the fracture. I also find that Epoxy 330 doesn't work well for filling fractures or vugs. It doesn't match the cab material at all.
Bob

[Bluesssman]

George, this is a great topic! I have several cabs with pits that are too nice to just toss or don't have enough material to reshape. I do not know anything about using fillers, but if they do work, I would use them on a few cabs I have that could use a good filler...

I will be following this thread closely!


Gary

[bobby1]

Gary,
I routinely use Opticon to seal fractures in my finished cabs. It is about 75% successful. Getting the Opticon to penetrate deeply into the fracture and make it not (or less) visible is the trick. I always treat the cab after it is fully cabbed and polished. If you try it before cabbing you have some problems:
1. You grind through the treated depth in some areas of the fracture leaving a partially sealed fracture and some shallow sealed areas that are readily visible.
2. Trying to retreat a fracture is rarely successful. The opticon won't go back under a partially treated areas.
3. The heat of dopping weakens the previously sealed fractures.
After the cab is completed it is almost mandatory to put it into an ultrasonic cleaner to get all of the polish out of the fractures, vugs and pits.
I thought I did a tutorial on this process, but maybe it was on another forum.
Bob

[bobby1]

This on is a Brazilian Agate sliced parallel to the bands. It is 2 1'2" high. An ugly fracture propagated from a small one on the back to a major one right up through the middle front. I had to do the Opticon fracture sealer treatment after I finished cabbing it this afternoon.
Bob

[Taogem]

Wanted to move this over here Bob..

You had absolutely great results with the Opticon !

[Mark]

Bob, where is the fracture?  Boy, that opticon worked great on that one.  I have used it a couple of times and it was ok, but the slab was often sticky.  I tend to use Hotstuff a lot more.  It does a good job of filling small pits and cracks and dries clear like agate.  Being an impatient person, I hate waiting for opticon to dry.

Mark

[bobby1]

Mark,
Here is a photo of the sealed fracture. I'm going to resand the cab to see if I can minimize the surface apprarance. It fully filled the internal part of the fracture so that the only thing that you can see is the surface crack under strong light at an angle. I soaked and heated the cab in Opticon for about 3 hours under my bench lamp, removed it (the cab was too hot to touch but I could see that the fracture was fully filled) and wiped all of the Opticon off. I then mixed a small amount of Opticon with hardener and applied a small line of it over the fracture. I placed it under the light for two hours and then filed the hardened Opticon line off. Altogether it took about 5 hours to do the sealing. I was busy taking the grandkids swimming most of the time.
I knew it would work well on this fracture because it was fresh and clean. It didn't have any reddish or black color intrusions that an old fracture often has.
I was pleased with the penetration that I got on the fracture. I changed my procedure slightly on this one as an experiment to see what depth that I could get the Opticon to travel. The difference is how hot I got the Opticon and cab. I figured that if I could get the cab hotter then the fracture would open up more to let the Opticon in. It worked!
Bob

[Taogem]

Interesting that you used the Opticon alone with no hardener to fill the crack first. I bet that because it had no hardener in it that it allowed it to seep down into the crack a whole lot better.

Think I read that Opticon by itself will harden eventually.

Seems like applying a small line of Opticon with hardener over the top that it would sand away leaving the Opticon with out the hardener exposed.

Good stuff Bob !

[bobby1]

George,
I've had Opticon for many years and have had no problems with it hardening on its own.
On another forum we had a chemist explain how Opticom polymerizes when it comes in contact with hardener. This action causes the Opticon within the fracture to harden. For many years this had been a question in my mind until  the explanation.
Bob

[Raqy]

Thanks guys.  I had always wondered about using opticon.  I have asked vendors at gem shows and they seemed a bit confused or just plain against it.  Has anyone here ever tried it on boulder opal?

[Mark]

Bob, that worked great.  I will have to keep that in mind.  I have a little cheap toaster oven that I bought for baking stones with opticon treatment.  I have heard of people using opticon with vacuum chambers to drag the stuff deep inside a fracture.  I've always wondered about coloring the option or hotstuff to try and match the stone color.  My wife has so many things from the art world, that i could use, like pigments, chalk dust, oil paints, etc.  On a side note, I have often had irritating chips, cracks, fractures, and breaks.  But recently, nothing.  Everything i have worked on for several months has gone well.  Not a single crack or chip.  I have been warming my cabbing water before use and i wonder if that is it?  I can still be kinda hard on stones when grinding, but I haven't had a problem in months.

Mark

[bobby1]

This is my method of treating fractures with Opticon. I almost always treat the fracture after all of the grinding, sanding and polishing steps are completed. I have found that treating before cabbing usually results in the fracture propagating more during the cabbing and the new fracture area is obscured by the Opticon so it can't be retreated.
I use my bench "gooseneck" lamp with a 100 watt clear bulb to heat the cab and Opticon. It provides more than enough heat to achieve a good healing action.

Here is a photo of the Opticon and hardener. This size container is the most popular and will do many cabs.

I use wells cut from an aluminum muffin pan to do the heating steps. You can shape a little spout on the edge to pour the excess Opticon back into its container.

I place the cab in the well and cover it with Opticon. Make sure that you have cleaned the cab with soap and water. I also place the cab in my ultrasonic cleaner to get all of the polishing compound out of the fracture. I have found that it is almost impossible to remove the polish with hand scrubbing. A few seconds in the ultrasonic is all that is needed. The last step before placing the cab in the well is to clean all the fingerprints off with denatured alcohol.

If the cab is a little large for the well you can easily reshape the well.

Next I place the well under the lamp.

Lower the lamp down as far as you can get it without the bulb making contact with the Opticon. I like to place something under the well as a heat shield to protect the bench top from getting overheated.

The heat will cause the Opticon to give off some odor so if this is objectional you can place a fan nearby. I leave the heat on the Opticon/cab for 3 hours. The cab will get so hot that you cannot touch it with your bare fingers! By getting it this hot the cab will expand and the fracture will be wide enough for the now very hot and fluid Opticon to fully fill the fracture.
After the three hours you can remove the cab with tweezers or pliers and wipe the excess Opticon off with a napkin. Wipe off all that you can get off. Carefully pour nearly all of the hot Opticon back into its container. Leave about 1 teaspoon of resin in the well.i

Pour this excess resin into a paper cup that has been cut down shorter.

Add a few drops of hardener. The instructions call for a 10 to 1 mixture of resin to hardener.

Stir with a wood popsicle stick.
 
Get a paper plate, cut a few pieces off a plastic ceramic tile spacer and arrange them on the plate. These will allow you to keep the treated cab up off the surface of the plate.


Lay the cab on the spacers and apply a narrow line of resin/hardener over the fracture line. Do the same on the girdle of the cab and on the back.

Place the cab back under the light and lower the lamp to it but not as close as before.

Leave it this way for an hour or so. Turn off the lamp and when the cab is cool enough to touch check that the Opticin has set up real hard.
File off the excess hardened Opticon and admire your success. As you will see, the less excess Opticon that you add over the fracture, the less you will have to file off.

I have tried to place the heated cab in the Opticon in a bell jar  under a high vacuum to increase the penetration of the Opticon with very limited success. The vacuum tends to vaporize the Opticon especially within the fracture and draws it back out of the fracture. Maybe placing the cab in a vacuum before any treatment will pull any water that might be in the fracture might help but generally heating the cab slightly before adding the Opticon will do the trick.
Bob

[Taogem]

Excellent.. Thank you Bob !