This idea initially sprang from a search for crystal based artwork. After poking around a bit, I came to the conclusion that the height of crystal art at the moment can be summed up as "Crystal on Rock", which I found both surprising and unfortunate. Crystals are beautiful and there are so many things that can be done with them. It is my hope that by posting this instructable, it will inspire you to create more interesting and unique crystal based art projects. I also think that 3d printing a sub-structure would be a good idea, but we'll have to try that later.
We'll do this in two parts: the primary art piece and the base. The primary art piece is the interesting bit. Searching for a good base was unproductive, so I built one myself. I'll walk you through some of that process as well.*
*More musings on the reasons behind this decision can be found in the Troubleshooting & Adjustment section at the end of this instructable.
Here is a short video of the end result.
A note on sourcing materials: I found it very difficult to find many of the items on the list. To save you time, I will list the sources I found for purchasing the parts as well as alternate vendors.
Part 1: The DNA Sculpture
Materials you will need:
2x Cast Acrylic Tube - 3"OD 1/4 or 1/8" wall thickness, 12" in length. (76.2mm OD 6.32mm or 3.18mm wall 304.8mm in length) Source: http://www.eplastics.com Note: Cast acrylic tube is higher quality than extruded but will cost a bit more. It is worth it. The striations in the clarity that come from the extrusion process make this less than desirable for the intended use.
1x Mirror backed Clear Acrylic Disk 3" in Diameter. Source: http://www.tapplastics.com Note: Thickness is unimportant.
1x Clear Acrylic Disk 3" in Diameter with two 9mm diameter holes placed roughly 0.5" - 0.75" from center. Source: http://www.tapplastics.com
1x Plastic tube cap 3" Diameter. Source: http://www.tapplastics.com
9-12x 1.06oz Food Grade Potassium Alum. Source: Local grocery store or online vendor. Note: Be careful what you are purchasing here, not all potassium alums are alike. I purchased a 1lb bag from an online source and what it made was mush instead of crystals. In the end I used McCormick's Alum. It is expensive, but it also makes very nice crystals and is relatively consistent in its quality.
42" of 16 gauge Ni-Chrome wire. Note: Do NOT use aluminum mechanic wire. It will react with the alum and rust.
12-16" of 24 gauge Ni-Chrome wire. Note: You can use aluminum wire in this case, but I recommend against it.
1x wooden or plastic rod measuring 1.5" in diameter and greater than 12" in length. Source: Local or online hardware store.
1x wood, plastic or cardboard block measuring 2" x 4"
2x EL-Wire, color and thickness of your choosing. Length ~1ft(304mm). Source: http://www.thatscoolwire.com http://www.sparkfun.com
1x 3v EL-Wire Inverter. Source: same as above.
1x Y splitter cable for el-wire power. Source: same as above.
1x AAA or Coin-Cell Battery pack for El-Wire. Source: same as above.
2x AAA batteries (if you go with the AAA battery pack obviously) Source: The bottom of a drawer in your home somewhere or anywhere that sells batteries.
2x Trial kit of Encapso-K encapsulation silicone. Source: http://www.smoothon.com
1x Aluminum (6061) extruded tubing. 3.5"OD x 3"ID x 2" length. Source: http://www.online-metals.com (Optional depending on taste and budget)
1x Aluminum (6061) extruded rod. 3.5"OD x 2" length. Source: Same as above. (Optional depending on taste and budget)
Several Popsicle sticks or other flat support. Source: Michael's Arts and Crafts had a big box for cheaps.
A bit of nylon line or similar. The smaller and more transparent the better. Source: Hardware store or fabric store.
1x Tube of Silicone Sealant Source: Hardware or Auto store. Also some grocery stores may have it.
1x Tube of Acrylic Adhesive Source: http://www.tapplastics.com
Graduated mixing cups Source: http://www.tapplastics.com
Large measuring cup
Tools you will need
~1.5" Diameter hole saw
~1/8" drill bit.
Latex or Nitrile Gloves (optional but useful for not leaving dirty, grimy finger markings all over the acrylic tube)
Wire cutters or Needle nose pliers
Digital Calipers (optional but useful)
Thermometer (optional if you are approaching it more scientifically than I have)
Safety First! None of the above are safe for human consumption, so don't.
Step 1: Grouping the Materials.
Out of the list of materials on the first page, separate them into the following groups:
Group one: Crystal Growing Chamber.
Acrylic tube, Plastic Tube Cap, Nylon line, Popsicle Sticks, Alum.
Group two: Wire coiling guide / substrate
EL-Wire, Ni-chrome wire, 1.5"D rod, 2"x4" wood/plastic
Group three: Final Housing
Encapso-K Silicone, Acrylic tube, Acrylic disks, Silicone Sealant, Acrylic Adhesive, Aluminum Tube and Rod.
Step 2: Building the Crystal Growing Chamber.
Step 3: Building the Wire Guide.
We will be putting a hole in the center of the bit using the 1.5" (38mm or close) hole saw. A pair of scissors would probably work if you are using cardboard.
First, grab the bit of 2"x4" (50mm x 101mm) plastic/wood/cardboard/whatever. Using a pencil/marker/eyeliner; make a mark in the center of the piece. Precision is not really required; you can eyeball this. Measure ~2" (~50mm) from the mark you made and place a mark. Do this again in the opposite direction. You should now have three marks on the material. The center mark is where the 1.5" (38mm) diameter guide rod will eventually go. The two side marks will be where the wire will be threaded through.
With the 1.5" hole saw bit affixed to your drill; create a hole in the center of the material where you marked. Swap out the hole saw with the drill bit and drill a hole on each of the other marks. Your finished piece should look nothing like this. This was done with the above tools minus the drill.
On to the guide rod. We will want to mark out every half inch (12.7mm) on the guide rod to help us in spacing our turns. So, with a ruler, go through and do so.
Place the rod through the guide hole, and you are almost ready to create the double helix.
Step 4: Building the Double Helix
Place the bent wire over on end of the guide rod and thread it through the wire guide. Move the wire guide to the top of the rod. Start turning the wireguide as you move it down the guide. As you are doing this, check the spacing of your turns to make sure they are relatively even. I think I used one full turn every 2 inches but this is really just a matter of preference. If you decide you would like more or fewer turns, remember to adjust the length of your wire accordingly. To actually calculate the required length, check the Troubleshooting and Adjustment section at the end of this instructable.
After you are happy with the coil you've made, fold the left-over material, if any, 90 degrees. Twist the ends around each other to make a firm support and remove any excess wire. Now you can remove it from the guide and set it down someplace where it won't get smooshed. On to adding the el-wire.* I usually start by placing the terminating end of one of the el-wire strands roughly 1"-2" over the center mark on the ni-chrome wire and secure it with a twist tie or electrical tape. After that bit is done, start wrapping the el-wire around the ni-chrome wire in whatever coil spacing works for you. This part may require a bit of adjustment if you find you end with too much left over. I have found it is best to leave around 3" of el-wire. The primary purpose in doing so is to allow yourself the ability to adjust how it hangs later on in the process.
Repeat that process again for the other strand of el-wire.
Next we add the cross bars.
* At this point, some of you may be wondering why I didn't just add the el-wire before making the coil. Initially I did and both strands died horrible deaths. Now I do it this way. EL-wire uses a phosphorescent coated core wire with another (corona) wire wrapped around it like a candy cane stripe of horrible fragile evilness. Well, the power connection point anyway. The rest of it seems to be okay. It is worth noting that having to remove the strand after you've got it on the support wire and have the crossbars wrapped snugly around it, having spent a day or so growing crystals on it, that you now have to remove, is a mildly annoying task that is best avoided.
** Apparently I made mine incorrectly. DNA wraps the other direction. If you want it to be correct, flip it. :)
Step 5: Adding the Cross Bars
For this step you will need the other length of ni-chrome wire. Measure and cut a ~2" section from it. Find a spot near the top of your coil. Place the section you've cut in such a way that you have enough material on both ends to wrap it around the el-wire and support wire. Once you have it placed, wrap it however you like and trim off the excess. The rest are done in the same manner down the length of the piece. The spacing of the crossbars is whatever suits your preference. I spaced mine every 90 degrees so that if you are looking through the coil from the top you see a rough plus shape. This process, aside from providing other spots for crystals to form, helps give the entire structure additional rigidity and can be used to tweak the shape of the coils if any are malformed.
This is an appropriate time to congratulate yourself and marvel in your creation by testing the el-wire to make sure it still works. If it does, and it should, yay! If it doesn't, see the troubleshooting section at the end of this tutorial. Now on to the crystals.
Step 6: Making the Crystal Solution.
This is how I approached it:
Start by filling the growing chamber up with water. Tap water will do, purified (actual purified) water will do better. The less impurities you have, the better your crystals will be, but all that being said, tap water will do. Once it is filled, dump it into a pot and toss it on the stove on high. Start stirring alum in. I go heavy on the alum and recycle what solidifies on the bottom of the growing chamber. Usually I find that 5-7oz of alum for roughly four cups of water works decently well. Boiling the water is not necessary, but if it does boil, it is not a problem. The water should be mildly murky, but if you put a spoon in and pull it up, the water in it should be clear with no tiny crystals. If it does have crystals, continue to heat and stir until they are all gone. Once this process is done, set your results off to the side (off of the heat) and let it cool as you prepare the next bit.
Step 7: Growing Crystals on Your Structure.
At the end that has the power connections for the el-wire, attach the nylon line by tying itself to itself in a loop under one of the crossbar supports. Then place the popsicle stick through the loop and use that to suspend the structure in the growing tube, making sure that the structure is not touching any of the walls of the chamber. Now, using a funnel, pour the prepared solution into the chamber through a coffee filter (or similar) and allow to sit overnight or overday if you are an early riser. The main growth will happen in 4-6 hours, give or take, depending on how the solution cools. In the end you should have larger clear crystals scattered on the surface of your structure.
If you want a more homogonous coating of crystals similar to the one in the first image of this tutorial, you can pour the solution into the chamber first and then submerge the structure. To enhance this effect, put the entire structure into the freezer first, allow to cool for a bit, then submerge it in the solution. The cold of the surface will cause rapid precipitation of the alum from the solution. This will result in a much tighter crystal grouping and the crystals will be smaller.
There are more ways to approach this. For additional control over the crystal growth, you can look into a different growing chamber setup. There is information available on the net for this, but I found this setup to work well enough for my needs. Unfortunately, it is rather tempermental and hard to control.
After the crystals appear to have ceased growing, very carefully remove the structure and hang. Be sure to keep the crystals from hitting the sides of the container. Do not handle the crystals! They are on there, but not very well and will break off at the slightest provocation.
If you wish to extend the length of your crystals, pour the remains of the liquid back in your pot and break up the crystals that have formed on the bottom of the growing chamber and dump them back in to the pot and reheat. Add another ounce or two of alum. Once that is reheated, pour it back into the growing chamber and allow to cool to near room temperature. The cooling is important due to the soluability of alum. At higher temperatures, if there is not enough alum already dissolved, it will actually break up the crystals on the structure and cause many to drop off. This can work in your favor if you like a larger range in scale of the grown crystals, as some will be big and some will be small. It can result in gaps.
A few notes on this entire process. It is variable. By that I mean if you change one part of it, the crystals you get will be different. If you bump it once or twice after it has been sitting a bit, it will be different. If you don't use a funnel, the crystals will be different. If there is a full moon and your breathing rate is +/- 10% of your normal breathing rate, the crystals will grow differently. There is a science here, but it requires expensive equipment to precisely control the growth environment and even then, the experts (okay...it was only one expert) tell me that there is more art than science in growing crystals. Inexpensive chambers can be built to make for more even and predicable results and I suspect there are more than a few instructables on the subject. If you wish to have more precise control, look them up. I enjoy the rather random nature of my approach. Makes for the occasional happy accident.
Another note on the type of pot you use. If you use a teflon coated pot, you can skip this. If you use an aluminum pot, expect the solution to eat your pot. Not in a major way, but it will eat away at the base of the pot and cause a shift in the color of your solution to an aquamarine/green. I have found that, while this is odd, it does seem to have a positive effect on the clarity of the crystals. I am not certain it is related as I have not approached this in a scientific manner, but it is something to watch out for. I am also uncertain of what is happening chemically here. I'm not terribly good at chemistry and I've put no time into figuring it out... I just said "Oooo! Pretty!" and got on about my work. However, if you do know what this about please feel free to chime in, I'd love to know.
Step 8: Preparing the Final Housing.
First, make sure the inside of the tube is clean. You will want to do this before you add the disk as doing it afterwards is an effort in futility.
Start by standing the tube on one end. Run a line of acrylic adhesive on the top rim. Do not place too much as you do not want any spill. After the adhesive is applied, take the mirror backed acrylic disk and place it on the top of the tube with the mirror facing down into the tube. Allow that to sit for several minutes to several hours depending on the adhesive you use. I let mine cure overnight. After that has cured, fill the tube with a bit of water to check for any leaks. I found that while a small amount of water would not often show leaks, filling the entire tube with it often would due to the increased pressure. After you have identified any leaks, fill them with silicone sealant. Alternately, you can just skip this and put the sealant on in large gobs to eliminate the possibility of a leak without getting any water on the inside of the tube (which may leave spots depending on your water). It is up to you. The sealant gets removed later regardless of approach....well, that is unless you choose not to use it in which case you don't have to remove it later.
Step 9: Encapsulating the Wire and Crystals in the Final Housing.
Start by placing the final housing tube, mirrored-acrylic-disk-side, down and making sure it is level. Suspend the sculpture as you did in the growing chamber with one minor modification. Because you will be filling this to the rim, you do not want a popsicle stick placed across the opening of the tube--it will result in a strip of bubbles in the silicone that, while not horrible or really noticeable, is not ideal. To avoid this, break a popsicle stick into a few pieces and glue them to the bottom of another full stick to form a stack that keeps it support on the rim, but not overlapping into the open area. Use additional sticks to adjust the hang height until you are happy with it.
Mix up the silicone according to the provided instructions. Start with one full kit (one bottle each of part A and B). Once mixed, pour against the side of the tube to minimize air entrapment. You can do this through a funnel as well if you desire. After that batch is poured, mix up the next one. This will not use the entire bottle so do it in smaller batches until it is completely filled. Allow this to sit for 24 hours at room temperature or as indicated by the instructions. Important note, do not move it after you have poured if at all possible until the 24 hour window has passed. It can result in visual tears inside the setup, dislodged crystals, or an implosion.
Also, at this point it may be beneficial to take the clear acrylic disk with the two holes in it and place it on top of the final housing after running the power leads from the el-wire through the holes. This will keep the power leads at the appropriate width so you don't tear the silicone later when you cement the disk in place. It is not necessary, but may reduce the possibility of tears in the silicone later when you adjust the wires to fit through the holes.
After this has cured, glue the clear disk to the top making sure to only place adhesive on the rim of the acrylic tube and not on the silicone. It might do bad things to the surface of the silicone... I didn't have the heart to check. Let this cure and set the entire assembly aside.
Next, the cap and collar.
Step 10: The Cap and Collar
I have included drawings of the parts for reference, or to take to a shop. The only important dimension is the inner diameter of the cap and collar; all else is relatively unimportant. In this instance, I wanted the bottom cap to have a hole so the light from the base could illuminate the sculpture, in addition to the el-wire. This necessitates an internal shelf on which the collar can sit; that is able to support the entire assembly but allows plenty of room for the wires to coil up. The inverter and battery pack also have to fit and still allow enough light through to light up the sculpture.
Alternately, you can substitue many materials for the aluminum. There are many different ways to approach this section other than how I did it; you can play with it and find what works with your budget and aesthetic. I did experiment with building a wood cap and while it didn't work great for me; I suspect that it is due more to a lack of skill and tools, than to the material itself. I think it could make a really nice cap if done properly. A rough outline of my approach on this was; to cut rings out of 1/4" wood, glue them together and then sand until it is relatively even. It did work, but in the end it didn't look how I wanted and I knew that aluminum was more in line with the aesthetic I was going for. But stacking material may be a viable approach. Such as: having a plastics company laser cut acrylic in such a way you could bond it together to form a layered cap. That could have a nice look, but I didn't try it. Again, so many ways this can be achieved. Play with it and find something that works best for you.
Step 11: Putting It All Together.
Once you have your cap; it should fit on the tube without the need of additional adhesives. If not, a bit of hot glue or similar should be sufficent. The collar should slip on and the weight of the assembly should keep it there. Again, if not, a bit of hot glue or a layer of electrical tape should provide the additional thickness required for a decent pressure fit.
Once those are both in place; start by cutting the two way splitter and wires down to a more managable size. You are just looking to excise any excess wire to take up less space. This may be an optional step, depending on the length of your wires. Once you have completed, or skipped, that step; connect the two-way splitter to the el-wire and inverter. Connect the inverter to the battery pack. Tuck all of this into the collar in whatever way works best for you. I used a bit of double sided foam tape to keep everything in place.
With that, you are done! Well done! Now, send me a link with pics! I'd love to see other people approach this. :)
Step 12: The Base
The basic goals of the design are to create an enclosure for the leds, motor, and associated electronics as well as to create a visually appealing base capable of supporting and rotating the art piece.
This can be created a number of different ways and I know very little of electronics. There is every chance that I have done something horrible and improper in all of this. Since there is electricity involved, use caution!
Laser Cut Clear Acrylic Sheet (6mm) Source: Any place that does custom laser cutting. http://www.pololu.com, http://www.ponoko.com etc
5mm threaded rod (1m) Source: http://www.mcmaster.com/
Hex Nut for 5mm threaded rod Source: Same as above
Hex Cap for 5mm threaded rod Source: Same as above
1000:1 Micro Motor (1595) Source: http://www.pololu.com (http://www.pololu.com/catalog/product/1595) (Alternates at Adafruit, Sparkfun etc)
Step-down voltage regulator Source: http://www.pololu.com (http://www.pololu.com/catalog/product/2101) (Alternates at Adafruit, Sparkfun etc)
Million Color LED Strip 19" Source: http://www.oznium.com (http://www.oznium.com/led-flex-strips)
12v 3.3A DC Power adapter Source: Included in the above if I recall. May have to be purchased separately.
(Optional) Small connectors like this http://www.adafruit.com/products/266 (You may have to shorten many of these)
Foam tape or hot glue
40 3mm Acrylic spheres. You actually only need around 32 but it is good to have extras, I got 100 for the discount. Source: http://www.usplastic.com
Access to a CNC Machine or Mill.
Autodesk Inventor 2012 Student/Unemployed version. You can download it after signing up at http://students.autodesk.com/ It gives you 30 days of full use and then it converts to the student/unemployed version. The only difference is that the files created are labeled as being created with the student version.
A note on the motor selection: I wanted an output turn rate of around 2-3rpm. That meant, given my gearing setup, that I would need a 14rpm motor. I searched for that and found this nice little compact 1000:1 motor from Pololu. If you would like a faster turn rate, look at the Troubleshooting and Adjustments section at the end of this instructable.
On to the videos... Fair warning, it is around 50 minutes long. I wanted it to be slow enough that someone could actually follow, currently it is running 2x actual time.
Step 13: Cutting the Threaded Rod
I ended up cutting it with a small hacksaw. I suspect there are easier methods, but I don't think I had any of the tools that would have made it an easier job.
That's all there is to this really. Try a cap on both ends to make sure it threads properly. I had one where the threads were bent and I was able to fix it by placing a cap on the one end, a nut on the other and two wrenches with a bit of force. It worked well enough. There are likely better methods for fixing this.
Step 14: Machining the Bits That Need It...
When you have finished, you should have a track that will fit the 3mm acrylic spheres and will allow the turntable to turn freely. It may sound a bit loud when you spin it, but when it is spinning under it's own power, it should be nearly silent if your track is cleanly machined.
Step 15: Putting It All Together
After you have all of your parts, including the laser cut base pieces, it is time to assemble it all. **
User bpark1000 added the following comment to the troubleshooting page, however, I thought I would include it here in it's entirety because of the essential information that it provides.
"A word concerning another problem you may have in time: the laser-cut acrylic plastic can crack due to internal stresses set up by the laser-cutting process. Any cutting process heats (and melts) the surface at the cuts. These surfaces cool and try to shrink, but are braced by the bulk of the unheated material. They remain in tension, and cracks can start from imperfections over time.
You can see these stresses by illuminating the pieces with polarized light and viewing through another polarizer. Stressed areas will pass light; the rest will be dark.
The solution is to anneal out these stresses. You take the parts (remove the protective paper) after fabrication and put them in an oven. They are heated to a temperature that allows stress to relieve, but not enough to warp (probably about 180 degrees F), hold at that temperature until the bulk is at that temperature, then cool slowly so that essentially the entire bulk cools together. This will require at least 12 hours. The large gear will be the item you must watch carefully for warping. Annealing can be done more slowly at lower temperatures. The quality of the anneal can be checked with the polarizer set."
Start by organizing the cut sections and removing any of excess/unused material. Leave the protective covering on the acrylic in place. It can be easy to smudge, scratch or foul the surface in any of these steps so leave it on until the very end.
Start by placing the parts in the stack in the manner in which they should be placed. Start with the base layer and work your way up. Make sure everything fits and looks good. This step is just to make sure everything is rotated and flipped appropriately for easier assembly later. After you are satisfied that everything does indeed look good, we can move on.
Remove all but the bottom three layers. Place your color cycling control thingy and the voltage controller in there to make sure it fits properly and to get a good idea of how you want to run your wires.
I started by soldering the pin connector that came with the voltage regulator to the voltage regulator. After setting that aside, I stripped the main incoming power wires. I then stripped the wires for the LED controller and connected them to the main power. I branched at that point: with two wires going to the voltage controller and then two out from there to the motor. The ground from the main and the ground for the motor were spliced together.
Before you turn this on; you will want to disconnect the motor and adjust the potentiometer on the voltage regulator to be close to 6V. The specific regulator I used can output up to 7.5V. The motor can probably handle that, but I prefer not to risk it.
Once that is set and measured; you hook up the motor and turn it all on. You should get lights and your motor should spin. If not, check the trouble-shooting section. Woohoo! Almost there.
Cut your wires down to the sizes needed to fit appropriately in the case, if you didn't do so initially. Start by placing a bit of foam backed tape on the underside of the LED controller. I left the voltage controller loose because, it is light enough that the wires kind of keep it in place and there is nothing conductive for it to brush up against. You could just as easily glue it in place, but initially, I prefer to keep it all easy to modify in the very likely event that I'll mess something up. Check the attached schematic (I use the term VERY loosely) for the basic circuit design.
After you successfully get all of the electronics and wires packed in there, you are ready to put the rest of it together. Lay on the additional layers until you get to the layer that holds the turntable. Coil your LED lights in a spiral with the terminating end in the center. Place this in the cavity. Lay on the layer that holds the turntable. Add the acrylic ball bearings to the machined ring. Put the turntable on the acrylic spheres and add the driving gear to the motor drive shaft. Put the other layers on and finish by adding the hex caps. With that, you should be done.
Turn it on to make sure everything works as it should. If you find it skipping, check the driving gear for level. If it is off true it may skip.
I hope you have enjoyed this Instructable and I hope it inspires or helps you in some way. If you have any questions or corrections, please do not hesitate to contact me.
If you did like this, please vote for me on one of the contests. Cheers!!
Step 16: Troubleshooting, Adjustments and Stuff.
In my search for a base I found many wonderful and inexpensive bases that, visually, would have worked for the project. Unfortunately, most of them could not support the required weight. Usually, they were in the 1.5-3lb range. This project weighs in at around 6lbs. In looking at the way they approached their designs I found what I saw as the problem. They were placing the turntable directly on the motor shaft. I thought that by creating a ball bearing setup where the motor was offset and had no weight directly on it that I could increase the potential weight capacity. This led me on a long search for bearings that would work....I found some, but none were the appropriate size or appearance. In the end I decided it would be best to just build a simple bearing setup into the base itself. The base is stacked profiles so this was possible and required only basic machining to create the bearing groove. The acrylic spheres are remarkably strong and according to the site I got them from, self lubricating, which does appear to be the case. It works really well considering it is less expensive than any of the bearings I saw. It supports the weight and is incredibly quite at the low speeds it runs at.
Creating the housing using profiles seemed like a good way to avoid a lot of work trying to mount things to other things. I just measured the part, and created a space for it to fit. This has a drawback that was unforseen to me: Nothing fits as cleanly as I expected. The wires in particular were not nearly as clean and space conservative as I thought. They were bulky and ill mannered. Just something to keep in mind when designing a base of your own. Add extra space!
In the process of creating this I have found that EL-Wire can be horribly horribly fragile around the power connection bit. If you find that your EL-Wires are not turning on follow these steps to diagnose and fix the issue.
Test the wires individually. If you are using a Y-splitter and one of your wires goes out, neither will work. Testing them individually will allow you to isolate the problem wire. Once you have narrowed it down to one of the wires (likelihood that both fail is small). The most likely cause of failure is the solder joint on the corona wire. You can try moving the wire a bit and often this will correct the issue. If it fails to do so, follow the instruction on this site to fix it.
Calculating how much silicone you need if you've adjusted the size of your tube.
The basic calculation is Volume = (Pi)(Height)(Radius)(Radius) This will tell you the volume of the tube, now you need to subtract the volume of the abstract shape you've created. Before you remove the item from the growth chamber, add water to make sure it is at the top. Now remove the sculpture. Pour the water into a graduated measuring cup and mark down the measurement. Now, fill the tube again to the top and pour that into a graduated measuring cup and subtract the first number from this second number. That will tell you the volume of your sculpture which you can then subtract from the volume of the tube itself to give you the cubic volume of silicone needed. The CC value of Encapso-K silicone is ~26CC per LB so each kit works out to being ~54CC.
If you find that your crystals are not growing, there is a chance that you have not dissolved enough alum into it. Try reheating the solution and adding additional alum to the mix.
If it has been sitting for four hours and has no visible growth, you may need to add more alum to the solution.
I can't think of any other issues off hand. If you have problems, please post them and I will do my best to answer them.
Calculating wire length for the sculpture.
To calculate the length of wire needed start with the desired height of the sculpture in the tube. In my case I needed roughly 10". So, once you have that figure, you need the desired diameter of the sculpture. In this case it was around 1.5". Now, you need to figure out how many turns you want to have. In my case I had them set at 2" intervals per full turn which gives me 3 turns . Next thing to determine is the number of helical coils you will have, in this case it is only two. So...
Desired Length + (Circumference of guide tube * Number of turns * Number of wires) . => 10" + (4.71 * 3 * 2) = 38.26" I think this may be an incorrect formula....but it does work well enough. *I corrected the original math, still not sure it is correct.
Calculating Gearing and Motor RPM for a specific outcome
This could be easier. Really. It confused me...a lot. Most of what I found was geared towards cars and motorcycles. The tool in Inventor for creating spur gears is what I ended up using. From there it was a lot of guessing at what the values should be since I don't fully understand what I am doing here.
First, some terms, formula and other information if you are unfamiliar with gears.
The most useful reference I found in explaining this... http://www.schsm.org/html/gear_ratio_calculations.html
I this instance, I have two gears of importance: the turntable and the driving gear (pinion). The turntable has ~124 teeth. The driving gear has 13. The motor turns at just under 14RPM (at 5.6v*). So, based on the information found in the fourth link...
Driver Speed * Driver Teeth = Driven Gear Speed * Driven Gear Teeth so...
14 * 13 = X * 124
X = (13/124) * 14 = 1.46
So, that gives me an output of 1.46rpm. Which is sufficient. I think I will likely redesign this section in the future for a slightly faster turn rate. Or buy a faster motor. One of the two.
*Adjusting that tiny potentiometer is really easy, but getting it nailed is a bit of a challenge if you don't have alligator clips. I didn't.
If your motor doesn't run; check the leads on the bottom to make sure they haven't been pressed into the housing. If that is not the issue; check the voltage. The motor is very forgiving, but it does require at least half a volt to start. See this page for more information: http://www.pololu.com/catalog/product/1595
Voltage Controller Issues
If the voltage is pegged at ~7.5V and adjusting the potentiometer doesn't change it, it is possible the potentiometer is dead. For me, this meant a replacement from Pololu. See this page for more information: http://www.pololu.com/catalog/product/2101
If, after coiling the LED strip, you find that you have lost a color or the entire strip has died, adjusting your coil will often fix the issue. It seems that there are some connections in there that can be a bit touchy about being bent too far.