By J. J. Geisler
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These are a couple of photos of the prototype bubble
counter for the Calcium Reactor.
This counter is built using 1 " clear acrylic tubing for the main
chamber, a 1/4" acrylic nozzle base, 1/4" OD clear acrylic tubing
for the nozzle and 1/2" clear acrylic mounting plates. !/4" NFT x
3/16" threaded barbs complete the ends. |
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| Closer shot of the nozzle inside the finished bubble counter chamber. |
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To create the bottom of the
counter I used scrap pieces of 1/4" clear acrylic. I used a 1
1/2" Lenox hole cutter in a drill press to cut 1 1/4" disk.
Each disk has a 1/4" hole in the center from the center drill bit as part
of the cutter. |
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To cut the nozzle piece I clamped
the tubing pieces to a board with the length marked on the board. Use
either a fine tooth dovetail saw, hack saw or other fine tooth equivalent (no
power tools...you'll never find the piece) Be sure and sand the ends of
the tube before you cut it to length. It is much easier to handle as a
long piece and then cut rather that trying to handle the little stub. |
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To cut the tubing I set up a stop block on the power miter box (chopbox).
The length is set at 4 1/4" for this bubble counter as the acrylic mount
it will attach to is 6" high. 4 1/4" tube, 1/4" nozzle
plate, 2 x 1/2" mounting blocks = 5 1/2". Hold the pieces firmly
while cutting and let the saw come to a complete stop before bringing the
blade back up or moving anything. Note: The bottom corner of the stop block is cut back. This is to prevent any small chips from lodging between the block and the pieces to be cut. Any important trick anytime setting up a stop. Any debris can stop your pieces from coming all the way to the stop and your pieces may be short. The stop block is firmly clamped in place using a 6" Jorgenson hand clamp (note shown). (Also note, this shot is actually 1/2" clear PVC pipe) |
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| Sand the ends of the tube after cutting. This is to remove any saw blade marks etc. This is done by laying a sheet of 100 - 120 grit paper on a smooth surface, holding the apposing edge of the paper, gripping the tube close to the bottom and drawing the tube towards yourself. Keep repeating and rotate the tube approximately 1/8 turn each time. |
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Position the main barrel
tube directly centered on the nozzle end-cap. Hole the barrel firmly in
position and bond using xxxxx or Weldon #x acrylic adhesive. |
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Several tubes showing the
ends from different angles. Note the bottom of the center tube. I
used a countersink to bevel to the intake of the CO2 nozzle tube. |
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Wrap a layer of masking
tape around the end of the tube to protect the face of the tubing. Using
a router with a carbide, double flute, ball bearing, flush trim bit, route the
excess material from the nozzle cap to create a flush end piece. Leave the
tape on and you can sand the router marks from the edge of the 1/4" end
piece. |
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| The Porter cable router has a flat top compared to the Bosh which has a rather round top. The PC makes a quick mini-shaper by using a wood hand clamp to hold it in place. This frees up both hands to get a better cut. |
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Polish the edges using a buffer. This can be one part of the project
that can make the difference from a hack job to a professional looking
job. How much time do you want to spend? I didn't spend much time
on the prototype. I recommend orbital sanding the surfaces to be
polished first. About 120 grit is fine for the main sand, you can go
finer grit afterwards if you wish. After sanding (leave the tape and
paper on) use the buffer. There are two degrees of muslin buffer wheels
used and two coarsenesses of rouse (there are more but most grinders only have
two sides). The first wheel is a more aggressive muslin, stitched
tighter. Also more aggressive rouse. This can be followed with the
second wheel and finer polish. Keep taking the brick of rouse and coating the wheel, buff the acrylic lightly, recoat and repeat. Don't spend to long on the wheel as you will heat your acrylic. This can cause crazing. Buff the bottom nozzle base and the mounting plates before assembly. |
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| Cut the mounting blocks. Another shot of a stop block and the chopbox. Blocks are cut 1 3/4" x 1 3/4" square using 1/2" clear acrylic. | |
| Drill the mounting blocks with 1/2" hole. This can also be touchy. Use even pressure for the main cut until you get close to the bottom our your acrylic pieces. Keep clearing the acrylic shavings from your hole. When you get close to piercing through the bottom of you piece go very lightly and keep a tight grip on you piece. Twist bits light to grab your piece as the bit pierces through the material and this can be bad. Another option is to drill the hole before the piece is cut to length. |
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| Route the edges of the mounting plates. Be sure and mark what is the front and what is the back side as one face will be left flat while the other three edges will be routed. I used a 3/16" round over bit. The flat face will be used to mount the completed bubble counter to an acrylic mounting bracket attached to the calcium reactor. | |
| Tap the mounting blocks. Mark the face your taping from and use this as the outside of the chamber. This will be the side you insert your threaded barb from. |
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| After the mounting caps have been sanded and polished they can be glued to the ends of the semi-assembled chamber. I created some shim pieces to lift the tube to the desired height (5/16" in this case) to center it on the drilled and taped openings. Place the masking tape on the mounting plates first, position the plates on the tube and then stretch the tape to hold the plates firmly in place on the tubes. Repeat for both ends. Make sure the plates are positioned properly and the flat portions of the mounting plates are aligned properly so the complete unit sets flat . I set the chamber vertical and glued the one end cap on the bottom first. After curing I turned the unit over and then glued the other end. |
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| Still working on the page......... |
