I. Appendix IV: Instructions for Building a U.V.
Radiation Chamber designed by David M. Hill,
Physics, Kansas State University
The radiation chamber used in the 1988-1991 NSF genetics workshops is an effective, economical,
easy-to-operate piece of equipment. Microorganisms, seeds,insects, small plants and
small vertebrates readily fit inside the box, and the exposure time to uv radiation
is conveniently controlled by the hand-operated shutter. Valid experiments producing
quantitative and qualitative results can be performed by Middle and High School students
within a 50 minute class period. Thesequalities make the radiation chamber ideal equipment
for middle school and secondary science teachers.
As this equipment is not available as a commercialproduct, instructions for building
this specialized boxare included for those persons needing another radiation
chamber. This is an easy project that can beaccomplished with a minimal to moderate amount of
woodworking experience. The materials needed are listedin Tables V-VII and the directions
are outlined in steps A-J.
First, get all the wood pieces listed in Table V,the hardware listed in Table VII
and have access to toolsand equipment listed in Table VI. Remember that "Number
of boards" and "Number of items" are for 1 box only. Multiply these columns by the number
of units you want to build. If you are constructing several boxes at the same
time, a jig will prove helpful during the initial process.
Table V. Wood Needed For Each Box
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Type of Wood Size # of boards Name of Item
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1/2" Plywood 20" x 11" 2 Top & Bottom
19" x 10" 1 Shutterplate
20" x 12 1/2" 1 Back
13 1/2" x 10 1/2" 2 Sides
18 15/16" x 9" 1 Door
3/4" Pine 19 x 4 1/2" 1 Front
Panel*
8 1/2" x 3/4" 2 Reinforcements
3" x 1" 1 Stop on
Door
18 7/8" x 2" 1 Baffle
Boards
1/4" Round 1/2" x 1/2" x 8 1/2" 2 Door
Rests
1/4" Masonite 10 x 11 1 Shutter
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* The shutter opening is another essential cut on thefront panel. This cut should
be a total of 10" in lengthand 9/32" deep, beginning 6" from the left side and
ending 3" from the right side. See figure 18.
Table VI. Tools & Equipment for Building Box
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Table saw - if cutting major pieces of wood yourself
Band saw - cutting shutter & fitting
Saber saw - Trimming aperture in shutter plate
Drill press - bit for shutter plate aperture - 3"
bit for indicator plug - 1/4"
Hand-held drill, screwdriver, hammer, pliers and file,
sander
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Table VII. Hardware Needed for Each Box
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Screws Size # of items Functions
Function
Wood
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#7 x 1/2" 4 2 - attach light fixtures
2 -attach door pulls
#4 x 3/8" 8 attach hinges
#7 x 1" 4 fasten top to rest of box
#6 1 1/4" long 1 pivot point for shutter
Nails 4-penny finishing 26-30 holds the box together
nail
&
Brads #17 x 3/4" wire brads 14 fasaten 1/4-round and
reinforcements inside box
hinges 1" - 2" 2 attach door to
front panel
door pull 4 3/4" 1 facilitates raising door
magnetic small 1 keeps door closed
latch during radiation
fluorescent 18 1/8" x 2 7/8" 1
light fixture
U.V. germicidal 15 watt G15T8 1 provides U.V. radiation
lamp 18" med. bipin
Lucite rod 1/4" diameter, 1 indicates light
1 1/4" long
In addition, use wood glue, wood putty, sand paper & black spray paint to construct and finish the box
properly.
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Step-by-Step Procedure for Building a Radiation Box
A. Attaching sides and back to bottom
1. Glue the back on the bottom keeping the
edges straight and flush, then nail pieces
together.
2. Glue each side to the bottom, aligning
edges and nail. Then attach each side to
the back.
3. The corners will match if all edges have
been straight. The sides and back sit on
the bottom giving a total height of 20"
for the sides and 19" for the back. See figure 19.
B. Attaching door rests and reinforcements,
starter holes for the magnetic
1. Place the door rests (1/4" round) on the inside
surface of each side, 1/2" from the front edge
and 8 1/2" high from the bottom. See figure 20.
2. Using glue and brads, attach the quarter
round so that the round surface is turned
toward the inside of the box.
3. Draw a line across each side 8 1/2" from
the bottom on the inside and 9" from the
bottom on the outside.
4. Glue the reinforcements directly under the
8 1/2" lines on the inside and secure the
reinforcements by nailing brads under the
9" line on the outside of the box.
5. Place the door against the rests and
measure approximately where the magnetic
latch will be attached.
6. Drill 2 starter holes in the bottom to
facilitate later installation.
C. Cutting and attaching the shutter to the
front panel
1. Mark the masonite
as indicated in the drawing. See figure 21.
Saw along designated lines and trim rough edges
with a sander.
2. Drill a
hole for the screw 3/8" from the bottom
and 3/8" from the left side. See figure 22.
3. To check for fit, drill a hole (3/8" from
the left side).
4. Insert the screw holding shutter the front panel
and move shutter back and forth through the opening.
See figure 23. If some area fits too tightly, remove
the shutter and sand the area until movement through
the opening is easy. Do not forget to round the corner
nearest the pivot point.
D. Cutting shutter plate and attaching inside
the box
1. Mark two dots on the shutter plate, each 8 1/2" from
the side edge and 5" from the front and back edges. See figure 24.
2. Using a special bit, drill a 3" hole at each dot.
See Figure 25.
3. Using a saber saw trim aperture to make a dome
edged cylindrical opening, approx. 6"in length.
See Figure 26.
4. Glue and nail shutter plate inside the box.
Reinforcements and door rest hold shutter
plate at correct height. Lines on the
outside of box designate the bottom of the
board and nails are used 1/4" above the
line.
E. Attaching front panel, shutter stop and guide
1. Using glue and nails, attach the front
panel with the shutter to the box. Fit
should be tight, use a hammer to align the
edges of front panel with the sides of the
box.
2. Close shutter and glue a stop on the
shutter plate. See figure 27 and figure 28.
This stop will prevent the shutter handle
from being pushed inside the opening.
3. Pull the shutter out until the aperture is
completely
exposed then glue the guide on the shutter
plate. The guide helps keep the shutter
in the proper place.
F. Preparing box to be painted
1. Using a punch, sink all nails and fill
with putty.
2. Fill all major wood gaps with putty.
3. Sand all rough edges and putty filled
holes until smooth. Run your fingertips
gently along sides and edges to check for
unfinished edges.
4. Let the box sit over night allowing the
glue to dry.
II. Preparing the top and the door
1. Glue and nail the baffle beam to the lid. The baffle will be 1" from
back of the lid and placed to leave 9/16" to the edge of the lid on
each side. See figure 29. The 2" extending downward inside the box
effectively blocks the U.V. light waves and the opening provides
necessary ventilation.
2. Draw guide lines at 8" and 11" from one
side of the door. Glue and nail (use
brads) the stop between these lines at the
top of the door. See figure 30.
3. Check the fit of the door. Use a sander or joiner to trim the door
if necessary. It must not fit too tight as wood can change size
depending on the humidity.
4. Putty all holes and sand edges until
smooth. Let the top and the door set
overnight.
A. Final preparation preceding painting
1. Using a course file about 1/4" wide, file a rectangular opening
about 3/16" deep in the top of the left side of the box. This
opening holds the cord from the light fixture. See figure 31.
Placement may vary, but putting the hole at the center works well.
2. Remove the dowel pin and the shutter to
facilitate painting.
B. Painting the pieces
1. Use flat black paint on the inside to
retard radiation and reflection. Use two
coats.
2. Use two coats of paint on the outside of
the box also.
C. Finishing touches
1. Test light fixture using a fluorescent
bulb. Center the fixture on the inside of
the lid and secure with screws.
2. Reattach the shutter with the screw.
3. Pull the shutter out until the aperture is
completely exposed and glue a stop on the
shutter. This stop indicates the aperture
is completely open.
4. Place the lid on top, measure and mark
screw sites and drill guide holes. Screw
lid firmly in place with 1" wood screws.
5. Using 1/4" bit drill a hole in the front
panel about 4" from the left side and
about 3" from the top. Insert the 1/4"
lucite plug light indicator with sanded
end extending about 1/2" from panel.
6. Install the magnetic latch on the left
side, using starter holes drilled in step
2.
7. Attach door to front panel with hinges
placed about 1" from outside edge. See
figure 32.
8. Center and attach door pull on the bottom
of the door. See figure 32.
II. The radiation chamber is complete
after it has been plugged into an
outlet and the light indicator
confirms the u.v bulb functions.
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Last updated Friday July 11 1997