It's a moment of inspiration. You just happen to see something or find something in a store or a garage sale or anywhere really and you think, wow I could make something pretty cool with that.
I recently had one of those moments. While wandering through a store I found these agates that had been drilled out apparently for candle holders. I like agates and geodes. All that sparkling and color are pretty eye catching. And I thought that instead of a candle why not put LED's inside it and light it up from the inside. The hard part was done, the drilling out the core, it had a big hole down the middle so all I had to do was fill it. My recent projects with marbles and wood and LED's and epoxy have helped me to see the possibilities of what can work. SO a new project was born.
Step 1: A Little Drilling to Modify Things
I needed to drill a small hole for the wires for the LED's. The big hole they made for the candle looks like it was drilled all the way through and then filled with a plug of epoxy. Probably easier for them to do it that way. It had to have been drilled with a diamond tipped hole saw. The quartz along the side of the bore was cloudy from the abrasive of the bit. I thought about drilling through the bottom which most likely would have been easier but then the wire would have been in the way. So a hole in the side was the way to go. A simple carbide bit for drilling cement should work, I thought. Turns out this stuff is really hard to drill.
After I drilled through the outer layer of rock and got into the quartz my progress slowed to a crawl. I had to turn on the hammer drill part of the drill and then had to add water because the bit was getting hot. It took a lot of effort and more than a half hour to drill this little hole in this thing. I now had great respect for whoever drilled out the core of this.
If I do this again I am getting a diamond drill since from what I have read it is the best way to drill quartz.
Finally I got through and amazingly it was in the exact right place.
Step 2: Adding LED Lights
Once you get the hole drilled put the power wires through the hole and hot melt glue them in place. Make certain the LED face is out against the quartz. Use a lot of glue on the little hole and be certain it is filled. Since you are going to pour epoxy into this and fill it you really don't want it to leak.
It took me a number of tries to get the LED strip to coil nicely around the bore hole. It just doesn't want to go easily. Fingers work the best for this, one holding it in place while the other one pushes more of the strip down. If you have thick fingers you might have a problem getting them in there with the strip. The pressure of the strip wanting to uncoil will hold it in place once its finally in there.
I took the left over LED strip and looped it down and back up in the hole. This will help to light up the glass that will fill the hole.
Once it is in place TEST the lights to be certain they work. Once you add the epoxy to this there is no fixing lights that don't work.
Modification ---- Fixing a Design Flaw
After all this assembly I realized that I should have hooked up the LED strip differently. The wires for the strip are pretty small since it doesn't use much power. This could be a problem in terms of physical damage. It would be pretty easy to break or pull the wires off that connect through the hole in the base. If this happens it will be very difficult, if not impossible, to fix because of the epoxy. What I should have done, and will do in the future, is use a piece of electrical wire here. Something like the wire from a thin cheap extension cord. or a lamp wire. Run it through the hole and tie a knot in it to keep it from pulling out of the hole. Attach the LED strip wire to that cord inside the agate. This way it will be a lot harder to accidentally damage the wires. The wires can carry far more current than will be needed but what you are looking for here is physical strength. We don't want someone to grab it by the cord and break the wires off.
Step 3: Filling With Glass and Epoxy
After the LED strip is in place add broken glass to start filling the void.
A special note here --- don't use plastic for this --- plastic floats on top of epoxy and the liquid epoxy will push the plastic up and out of the form.
I did an instructable all about this process including how to crack glass. If you haven't done this type of thing before you should read through that one for full detailed instructions.
As you fill the hole shake the agate and tap it to get the glass to fill in the voids. Use smaller and bigger pieces of glass together so they fill in the empty spaces. The more glass you use the less epoxy you will need.
Make a hot melt glue dam around the top so the epoxy does not run off. Once it is filled with glass you can put whole marbles on top for a finished look.
I mixed up 60 CC of epoxy for this (30 and 30) and had about 10 left over. It took less than I thought it would so that means the glass settled really well. Pour it in slowly and let it work its way down. Big bubbles should come up as the epoxy fills the gaps. The above instructable has a big section on pouring epoxy so you can read that for more in depth directions.
I plugged the lights in while I was doing the filling. The LED string did generate heat which helped the epoxy flow and eventually sped up the curing process. The epoxy I used cures very slowly so there was a lot of time for it to flow and get into all those little places. This allowed for the entire column of glass and lights to be completely filled so it made for a very solid piece once cured.
Step 4: Night Light
I liked the finished result. This one worked out good. I am now on the lookout for more agates and geode's
When turned on to full brightness the LED's do generate heat. After being on for about 4 hours the temperature of the agate measured at 105 degrees F. Since it is essentially a solid block that is probably as warm as it will get. So it makes a nice hand warmer but not hot enough to be uncomfortable to hold much less be a fire hazard.
I added an in line LED dimmer/controller and with it turned down just a little it stays at room temperature. Some might prefer it that way anyway since on full power it does put out a lot of light.
The entire agate lights up and glows, not just the polished face. I almost like the backside better since it is more colorful with all the different rock showing up.
It would probably be possible to use an RGB light strip although I don't know if I would like the whole thing changing color. But I might try it.
An easy and fun project and something that could be around for a long time.
By the way, this is totally waterproof, if you waterproof the little cord it could be used outside as well as inside. Outside it would make a fantastic path light. But you might need more than one of them.