Drivers
#1
Posted 26 July 2003 - 08:22 PM
DRIVERS are a very easy device to make. Ideal for beginners. The basic idea is to solidly compact a black powder composition into a cardboard tube then put a clay choke in one end. Though some tooling is required it can easily be improvised.
CARDBOARD TUBES: This description of driver construction deals with 1/2" inside diameter tubes. The wall of the cardboard tube should be at least 1/8" and approx. 4-6" long. They can be purchased from several pyrotechnics suppliers, scrounged out of the garbage can or you can roll them yourself.
RAMMERS: these are nothing more than 1/2" rods made of brass, aluminum or wooden dowells. This is what your going to use to compact the bp into the tube. They need to be a couple inches longer than the tube you will be using. Typically three are used. One needs to be 7-8" in length and it is required that you bore a 3/16" hole in the center of one end about 1" deep. The second one also needs to be approx. 7-8" long and is cut square on the ends but has no hole. The last one is cut about 3-4" long and is a handy size to have as you are finishing off at the end.
RAMMING BASE: Another simple item. In it's most simple form...a block of wood with a 1/8" dia. nail sticking out about 3/4". A slightly more complex version has a 1/2" dowell that protrudes 1/4" from the block of wood and the nail sticks out approx. 1/2" from the dowell. The later arrangement has the advantage of putting the clay choke back from the end of your cardboard tube. Why is this good you ask? As you pound in the clay to form the vent/nozzle it will expand and create a slight bulge in the paper casing. This helps to keep the clay vent locked into place. Ramming clay at the very end of a tube creates a belled out tube and will have a tendency to just blow out. Just bore a 1/2" hole into a block of wood about 3/4" deep. Now drill a tiny pilot hole in a 1" piece of dowell to accomodate your nail. Slip the nail into the 1" long dowell and glue it into the block of wood. Your all set.
DRIVER COMPOSITION: to keep things simple we will be using a modified black powder comp. Potassium nitrate - charcoal - sulfur.
Potassium nitrate 70 %
Charcoal(airfloat) 18
Sulfur 12
These percentages can be manipulated til the cows come home. Simply mix them together dry and use as is to start with. Mixing the mess together with some water(approx. 20%) and running it through a window screen will get you a soft grain powder that is great to work with. I presently have a small amount of spider comp sitting on my window sill that have been mixed and manipulated and after they have been tested I will report on the performance of each.
Spider comp: after doing some tests it is evident that a milder composition may be required
KNO3 60
charcoal 32
sulfur 8
This mixture was moistened 1/1 water and isopropyl alcohol , riced and let to dry,then rammed in a tube. It sputtered and burnt for several seconds. The sputtering is due to dross building up at the nozzle and in some cases may cause failure because pressure builds up. A smoother burn can be achieved by ball milling the ingredients.
*NOTE* It is nearly impossible to give a sure fire composition that will work the first time. Variables such as tooling specs., ramming procedures , quality of chemicals all have a big influence on how things turn out.
CLAY: this is to make the clay nozzle.Kitty litter will work just fine for the time being. You need to crush it into a powder before you use it. Bentonite clay and some grog also work very well. Neither one requires any water. The pressure of the ramming makes a good hard plug. If your tooling is of good quality the clay nozzle will even look a bit shiney.
Lets give one a try. Take the cardboard tube and slip it over the nail and dowell that is mounted into the wood block. Insert the dowell with the hole in the end and push it down the tube until you feel it go past the nail and stop on top of the dowell nub. Take a pencil and make a reference mark at the top of the tube right on the rammer. Remove the rammer. Take about a half teaspoon of powdered kitty litter and pour it down the tube. Push the rammer down on top of the clay and give it a few whacks with a mallet. Repeat this process until you have formed a clay plug that is approx. 3/8" thick. You'll know it's that thick because you thought to mark the rammer and that mark is now 3/8" from the top of the tube.Remove the rammer and turn the ramming block upside down and tap out any loose clay from the tube. Don't take the tube off the ramming base. Take a teaspoon of driver comp and dump it into the tube right on top of the clay nozzle you just made. Bet you wish you riced your comp about right now. Insert the long rammer with no hole into the tube on top of the comp and tap it 5 or 6 times.(a general rule is to ram one increment of comp at a time and not to exceed a diameter in length per increment) Repeat this process of ramming until you reach about 3/4-1" of the end of the tube. Now switch back over to clay and ram a bung that is approx. 3/8" thick. With a gentle twist pull the driver off the ramming block. You just made a driver.
General inspection: look down the clay nozzle and see if you can make out any black. That of course would be the driver comp. That's good. If you can't see anything use a 1/8" drill bit and very gently twist it down the oriface of the nozzle. Give it a couple of easy turns and pull it back out again and look to see if any black has fallen out. If not just keep gently drilling with your fingers a little at a time until you start seeing driver comp.
Now take it outside and bury the little rascal in the dirt and stick a fuse of some kind in the nozzle. Light the damned thing and run for your life. She's gonna blow. Actually it should burn pretty good. If it does go bad then just add come charcoal to the mix.
NOW WHAT YOU ASK ? There are countless things that a driver can be adapted too. In it's mildest form it's a modest fountain. In a more glorious version it can be strapped to a girandola along with a couple more and you will weep endlessly when it takes off. The most common usage is on a wheel. Or... it's a rat or an end burning rocket or.....
Helpful hints and observations
If you find that your driver does not burn as fiercly as you had hoped there are a couple things you can do. The easiest thing is to take a 1/8" drill bit and slowly bore the core a bit deeper. This increases the burning surface so more powder is burning at one time. The other thing is to mill the driver comp in a ball mill. Ramming a good quality meal powder and fine tuning all the elements will result in an end burning rocket.
If they blow up....enlarge the vent with a larger size drill bit. 2.)Slow down the mix with some charcoal. 3.) The vent is too deep, pack some driver comp back into the hole. 4.) The clay plug is blowing out. Ram the clay harder next time. There should be a very slight bulge on the outside of the case where the nozzle is formed. Not so much that you split the case though. 5.) The vent hole is clogged from the fuse being jammed in too hard. All that is needed for ignition is some fire to spit down the oriface.
My nozzle breaks apart when I take it from the ramming base...put a tiny piece of wax paper over the nail then slip the tube in place. 2.) Ram the clay more solidly on the next try.
Matt and phildunford have good sites. Go to the members list and click on their www's for pictures and other info.
[Edited on 29-7-2003 by bernie briden]
#2
Posted 27 July 2003 - 12:02 PM
-Matt
#3
Posted 27 July 2003 - 01:25 PM
#4
Posted 27 July 2003 - 01:47 PM
#5
Posted 27 July 2003 - 03:22 PM
#6
Posted 09 August 2003 - 04:54 PM
You site is well cool. Love the updates and the spiked shell for Bernie.
Your new firing panel is well cool.
Hitachi are a Japanese electronics company - they make loads of TV's and hi-fi's etc. for purchase over here in the UK.
That's just 'cos you were asking.....
#7
Posted 09 August 2003 - 05:45 PM
#8
Posted 10 August 2003 - 01:41 AM
I made a 12mm driver before but i didnt ut it on my site, well im doing it as we speak so check back shortly. Im sure everyone doing this project would whoop my ass because my fountain wasnt thhat great, but then again I dont think any 12mm fountain would be.
-Matt
#9
Posted 18 August 2003 - 11:46 AM
#10
Posted 18 August 2003 - 01:50 PM
I disagree. I?ve seen some amazing half-inch fountains. Part of the whole art is to prefect. I still spend a lot of my time on building fountains. Some of them are near spectacular ? but still not even close to some of kimbeldon ones. Try for example a spark-changing fountain. At the bottom of your fountain load 76%BP, 24% aluminium 60-250# (any in this range will do), and the top half should contain 76%BP, 24% iron #60 (choose one with high carbon content, so you get nice branching sparks).Indeed I do
I made a 12mm driver before but i didnt ut it on my site, well im doing it as we speak so check back shortly. Im sure everyone doing this project would whoop my ass because my fountain wasnt thhat great, but then again I dont think any 12mm fountain would be.
-Matt
This should get you started. Now prefect your compositions ? for example, using some formulas with KNO3 + Barium nitrate + AL get you brighter sparks then those achieved with BP + AL. A change in the tune of the spark in the middle can be very impressing.
Good Luck, and Stay Green!!! BigG
#11
Posted 18 August 2003 - 01:59 PM
24 KN03
4 C
4 S
10 Al (Tiranti is fine).
Make sure the KNO3 is milled to dust (without Al of course..... ) and that the C is pine and not too fine (hmmm....that rhymes doesn't it.....).
Add the Al to the mix at the end.
This one is most impressive when rammed into a strong tube.....
#12
Posted 18 August 2003 - 02:32 PM
I smell a twist on Tom's Iron #1 formulaFor a bright, almost 'fire fly' effect try:
24 KN03
4 C
4 S
10 Al (Tiranti is fine).
Make sure the KNO3 is milled to dust (without Al of course..... ) and that the C is pine and not too fine (hmmm....that rhymes doesn't it.....).
Add the Al to the mix at the end.
This one is most impressive when rammed into a strong tube.....
#13
Posted 18 August 2003 - 11:51 PM
-Matt
#14
Posted 19 August 2003 - 10:35 AM
-Matt
#15
Posted 19 August 2003 - 12:00 PM
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