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The original description of this project calls for a paper tube with a 4 inch outside diameter, 2 inch inside
diameter and 1 inch thick walls. This is required because of the tremendous pressures that must be
withstood by the fountain. Until recently, this kind of paper tube could not be purchased, but you can now get
them from Dawntreader Pyrotechnic Specialties. It is made
by bonding one tube inside another to achieve the total wall thickness of 1 inch. If you purchase them separately,
the outer tube can be reused and the inner tube is discarded after use. This will save you a few bucks if you are
a penny pincher like me. Here you see a picture of the tube assembly at the right and the separate inner and
outer tubes at the left.
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An even more thrifty approach can be achieved if you want to go to the effort of rolling your own tube. In the
picture is shown a Skylighter tube with a 2 inch inside diameter and 1/8 inch thick walls. This is used as a
mandrel over which is rolled a paper tube with a wall thickness of 3/8 inches for a total of 1/2 inches. This
assembly is then bonded inside a common 3 inch paper mortar tube with 1/2 inch walls or a Dawntreader outer tube.
The inner Skylighter sleeve is not glued in place, but is used as a replaceable liner. This way, your disposable
material cost for a fountain is only about two bucks. The problem is that rolling an inner tube this large is
no simple task. It must remain very round and uniform to fit perfectly inside the outer tube. I succeeded only
after using a lathe to true up a tube wound with 60 pound craft paper and fiberglass resin.
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Since this fountain is made by compressing the composition inside the tube, a suitable ram must be made for the
job. You can buy a premium quality, custom turned, hardwood ram from Dawntreader for about $50. They also sell
an economy version of the wooden ram for about half that much. Then we come to the penny pincher alternative,
which I, of course, opted for. The picture shows an eighteen inch length of 1 1/2 inch black pipe with threads
at one end only. Hardwood and plastic plugs are made with a lathe for the non threaded end and a t-fitting with
a threaded metal plug is used at the other end. The plugs with holes in the middle are for use with the spindle
tooling pictured below while the flat bottomed, solid plug is used if you plan to drill out the core with a
very big drill bit.
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If you are fortunate enough to have access to a metal lathe, a spindle such as this one can be made to form the
central core of the fountain. It consists of a stainless steel spindle which has an aluminum collar to align
the paper tube. This spindle and collar are then mounted to a ramming base of 3/4 inch aluminum plate. The
spindle is designed to produce a core length of 12 inches, which is 2 inches longer than the core produced by
the drilling procedure described below. A longer core length means more surface area is allowed to burn at once
and a higher internal pressure will result. This translates to a higher plume of sparks during operation, but
the risk is higher of a nozzle blowout or failure of the tube to contain the extra pressure. A dimensional
drawing of this tooling can be found
here. The spindle puller is an essential
part of this tooling because without it, the extraction of the spindle from the compressed clay and composition
is almost impossible. If you belong to the class of poor unfortunates that don't have access to machine tools,
then you are left with the equally effective alternative of drilling out the core with a hand drill. The bad
news is that you have to shell out $22 for a 7/8 inch by 18 inch long drill bit called the "Naileater" at Home
Depot. This method of making the fountain core is described and illustrated below.
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With the tooling and supplies gathered up, the project is begun by treating your steel filings with boiled
linseed oil or paraffin. I purchased Skylighter iron borings (CH8160) and medium iron filings (CH8156) for this
purpose. The borings are rather large, thin curls that need to be crushed a little to be usable. I did this
with an old meat grinder and then screened out the fines to yield +20 mesh chips. To this is added an
equal weight of the medium filings screened for 20 to 40 mesh. This mixture is then coated with the linseed oil
and sprinkled thinly on waxed paper to dry. It takes 4 or 5 days to dry, so you need to plan ahead.
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Mixing the fountain composition is fairly straightforward. If you plan to drill out the core of your fountain
with the "Naileater", you will need a batch size of 1400 grams. If you use the spindle tooling, you can get
away with a batch of 1050 grams, because the core material is not wasted. For the first case, 1000 grams of
potassium nitrate is added to 200 grams of red gum and screened together several times to get an even mixture.
Then 200 grams of the treated filings are folded into the mix by stirring. A good sized bucket or bowl with a
lid will be needed for this mixing task. A spray bottle is then used to mist the mixture with solvent while
stirring to dampen it. The Davis instructions call for a 50% mixture of water and alcohol, but I used pure
alcohol to speed the drying time of this fountain. The consequence is that the mixture must be kept in a lidded
container prior to and during the ramming stage or it will dry out in the bucket. Dry composition will not
compress well and might lead to dangerous voids in the final fuel grain.
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Ramming the fountain full of explosive composition can be an exhilarating experience if you're young and full
of energy. Unfortunately, I'm not so I devised a different solution, but, for the rest of you, manual ramming
is a viable method. First, a 1 1/2 inch plug of hardwood is placed in the nozzle end of the tube without any
glue. It will be removed later and is only used to recess the nozzle to make room for a drilling guide. The
tube is then positioned nose down in a big bucket which is filled with potato sized rocks. This bucket is then
placed on a solid concrete floor for the ramming station. Three increments of 100 grams each of bentonite clay
are rammed in the tube to form the nozzle, which will occupy three inches of length in the tube. This is done
by striking the ram with the biggest sledge hammer you can get your hands on. I used the splitting maul shown
in the picture. If you use the metal ram, you must expect that the ramming could cause sparks from the two
ferrous metals impacting each other. The safety minded person would make sure no loose composition is on top
of the fountain tube, on the floor or anywhere near the ramming station. If the risk gives you the "willies",
then you should buy a Dawntreader hardwood ram or consider the method shown below.
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Not needing to prove my manhood by using the manual ramming practice mentioned above, I decided to modify my
rocket press to give it enough vertical
clearance to handle the task. Two more 2 foot long threaded rods were
used to extend the 3 foot rods used in the original hydraulic press. A single nut seems to be strong enough to
handle the forces of the press when used to join the 3/4 inch threaded rods together. Using the rocket press,
the process of consolidating the fountain composition in the tube is safer, easier and will give you better
compression. This alternative is a clear winner in my book.
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After the 11 inch column of fountain composition and 3 inch end plug of clay have been rammed or pressed, you
can immediately drill out the core with your "naileater" auger bit. If the spindle is used, a 13 inch column of
composition is needed and you can, of course, skip the core drilling step. The core is drilled by removing the
solid wood plug from the nozzle end and replacing it with one which has a 7/8 inch hole drilled in it to act as
a drilling guide. A piece of tape is placed on the drill bit at 14 1/2 inches from the cutting edge at the tip.
This marks the hole depth and sets the core length at 10 inches beyond the clay nozzle. The core is drilled
with the tube clamped horizontally on the work bench with the nozzle end extending over the edge a few inches.
A tray is placed under the nozzle to catch the tailings of composition and nozzle clay as they are drawn out by
the auger bit. The drilling is done with a variable speed drill at very low speed to avoid any heat build-up.
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This fountain will need a healthy fire to get it going. A fuse is made by using a 4 foot length of quick match.
The paper tube is removed from an 8 inch length on one end and 18 inches on the other end. Two lengths of bare
black match, about 6 inches each, are cut from the long exposed end. These are bundled in parallel with the
exposed length of black match that is still attached and tied with string. The three stick bundle is then
painted with nitrocellulose lacquer and dusted liberally with 3FA black powder. The bundle end of the fuse
assembly is then placed as far down the core as it will go. I like to add a bit of decorative flair by using
colorful wrapping paper as a nosing to hold the fuse firmly in place.
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It is important to provide a secure base for this fountain. This one is built like a Christmas tree stand
with two crossed pieces of wood. A short length of PVC is used to firmly clamp the base of the fountain to
the stand. The stand has holes in the ends of the cross pieces where tent pegs can be driven through
them into the ground to form a very secure anchor for the whole piece.
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Here is the result of all this effort, prior to lighting the fuse. If you don't want to dress up your creation
with party paper, plain craft paper will do the nosing just fine. The finished product is fairly impressive
either way by virtue of its size and hefty weight.
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Here is the result of all this effort, after lighting the fuse. The picture was taken from a distance of 40 feet
with no zoom. It manages to fill the field of view with a 60 to 80 foot shower of beautiful golden, branching
sparks. It makes a loud, throaty hissing noise like a rocket and is guaranteed to widen the eyes of even the most
macho of your friends.
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