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Warning:
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Exercise proper safety precautions when working with any electrical devices.
The author of this document is not liable for your mistakes. This page is
provided for information purposes only. The reader assumes all liability for
use or misuse of any information contained herein.
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Introduction:
This FAQ will show you how to build a Deluxe Heavy-Duty Adjustable
Micro-Parabolic Reflector for Under $25 using simple parts from the hardware
store. All parts are available at Revy. The dish can be obtained at the
Super-Store. Build as shown in diagram, left to right - add reflector
last.
Simply follow the instructions in this drawing:
If built according to the drawing the reflector will be approximately in
focus and ready to operate. Powerful spot beam is perfect for smaller bulbs
and cost is great for smaller grows. Push reflector downward slightly (1/4 -
1/2") for less intense beam. Pull reflector upward slightly (1/2 - 1") to
cook everything.
Bulb is shown in drawing - top of inner envelope should just barely project
through hole cut in bottom of reflector. Approximately half the light going
upwardly is caught and all side light is sent straight down.
There is a 1/4" gap between bulb and cut-out to allow upward air flow. No
fan cooling needed. After it has been on for hours (with a 400W PSMH bulb) I
can touch the edge of the reflector as long as I like - it is not at all
hot.
This drawing was measured for a 5kV mogul (3" long). All parts are to
scale. Print on 8 1/2 x 11" paper if desired, this will help immensely.
If you have questions
please post
them in this thread. The moderators of the FAQ will
compile your comments and fix this up for us should the need arise.
Tools Needed:
Tin-snips. Hand drill. Drills for bolt holes. Felt
pen. Ruler might be useful.
To Assemble:
1) Lay post anchor sideways on work table.
2) Put octagon box inside post anchor and mark holes on bottom with felt
pen.
3) Lay post anchor base down on flat surface.
4) Hold 3.1x7" nailing plate against side of post anchor and use felt to mark
for holes.
5) Drill marked holes. Bolt box into post anchor and bolt the plates through
sides of post anchor and octagon box. Put nuts on these bolts and
tighten.
6) Place slotted plates near end of slot about 3/4" from end of 3.1x7"
plate and mark with felt pen.
7) Mark octagon box lid and snip edges with tin-snips so it can screw onto box
and fix inside post anchor. Make sure pop-out on lid is inside so mogul can
sit flat.
8) Place mogal central on lid and trace around it. Measure mogul bolt holes
center-to-center distance and mark for drilling. You may need to replace mogul
bolts with different ones if you can't find nuts for mogul
bolts.
9) Attach 90' BX connector and thread wire - attach ground. Wire mogul. Attach
box lid.
10) Use ruler to measure distance between sides of post anchor box and use
string/tape to maintain distance throughout length of device. A little
bowing/bending is OK - you can be out a 1/4" but it is best not to be. Ends of
3.1x7" plates should be same distance apart as width of cut octagon box
lid.
11) Attach "L"-shaped slotted connectors to 3.1x7" plates. Use pen to mark
bottom of reflector through holes on "L"-shaped slotted connector plates.
Holes should be a "short distance" from 'flat-bottom' of bowl.
12) Measure distance between plates and compare to bulb diameter - make sure
there is 1/4" clearance on each side. IF needed remove string/tape and widen
spacing - metal must NOT touch glass bulb when completed.
13) Drill reflector (bowl) to make a 1/2" (or larger) hole in center. Put
tin-snips through hole and cut out circle a tiny bit smaller than flat-bottom
of bowl. NOW you can remove bulb from protective package and see if it will
pass through hole with a 1/4" clearance on each side. Make hole in bowl's
bottom a little bigger if needed. You should leave small amount of bowl's flat
bottom remaining. After using tin-snips to cut bottom of bowl put bulb back in
protective package.
14) Check to ensure that "L"-shaped slotted connector plates can be attached
to tiny remaining portion of bowl's flat bottom. If you've cut away ALL the
flat part (and you should NOT have to) then you can bend "L"-shaped slotted
connectors plates to follow curvature of bowl. Mark bowl with felt for
drilling. Drill bowl carefully, DON'T bend, dent or scratch
reflector.
15) Assemble everything and tighten bolts firmly (don't forget to ground
Octagon box).
16) Wing nuts should be firmly tightened (by hand).
17) Screw bulb (through hole in bottom of reflector) into mogul.
18) GENTLY loosen wing-nuts and look straight at bulb's axis. Adjust
reflector so bulb appears magnified.
19) Tighten wing-nuts firmly. Remove bulb carefully, put away safe.
20) Hang fixture. Reinsert bulb. Try it out. If focus is poor you can
readjust.
Once you make one it will seem much easier. It only takes 1 1/2 hours to do
it slowly.
Good Luck,
The Prof.
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