DIY Canister Light and Lighthead

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After some research, I decided to take my first shot at a can light. It was a success. The details of this light are as follows.

Light Head:
2 D-cell Maglite (most use C-cell, but I had this one already)
JB Weld
Glass lens - http://www.zbattery.com (must order $5.00 min.)
MR16 bulb with glass shield 20W & 50W - Lowes
1 7/8" OD, 1/16" thick o-ring - Tractor Supply (Indiana, what do you expect.)
Brass 5/16" hose fitting 1/4" NPT thread - Lowes
brass 1/4" NPT thread nut - Lowes
5/16" clear tubing - Lowes

Canister:
14" of 2 1/2" OD Aluminum tube 1/16" wall thickness (had it lying around)
2-2 1/2" aluminum discs (fly cut out of .10" aluminum sheet)
2-rubber 2 1/2" caps with screw hose clamps for PVC tube - Lowes
SPST switch 10Amp 120V - Lowes
Rubber environmental screw on cover for switch - Lowes
Brass 5/16" hose fitting 1/4" NPT thread - Lowes
All purpose glue for metal, plastic, wood - Lowes
Misc. wire and plugs for batteries (had lying around)

Batteries:
20- C-sized NiCad 1500mah batteries (Common RC hobby batteries, there are better choices out there. I had these and the chargers.)


To make the light head, I cut the main body of the light to 4" & sanded 1" of the anodizing off the outside of cut off end. Then I sanded the threads out of the light head, cleaned both parts and bonded them together with a generous amount of JB Weld. The squeeze out can be wiped clean and radiused on the inside prior to cure for the best seal. I drilled and tapped (1/4" NPT) the cap for the 5/16" brass hose fitting. I installed the fitting until tight, placed some all purpose sealant around the union on the inside of the cap, and screwed the brass 1/4" NPT nut on tight. At this point, I JB welded the cap onto the base of the light head. The sealing of the lens was accomplished by inserting a MR16 bulb with glass lens in the head, followed by a 1 7/8"OD, 1/16" thick o-ring, glass Maglite lens, stock Maglite o-ring, and lens cap. This is where things get a little interesting. Some people had to cut down the groove inside the light head so that this could all be assembled without putting too much stress on the lamp, causing it to break. I found that I could screw the lens cap ALMOST all the way down before it would stress the lamp. I decided to tighten the cap until it felt snug and no more.

The canister was a cake walk. I cleaned the ends of the tube to eliminate burs. Then cut two aluminum caps the size of the tube OD to fit between the rubber caps and the tube. I thought this would be necessary because the pressure would bow the rubber inward while descending. I placed the cap inside the rubber boot and slipped the boot onto the bottom part of the canister, tightened the hose clamp, and it’s done. The other cap required a little more work. I located where I wanted the lead wire and switch, then drilled locators in the aluminum caps and located their position on the rubber cap. I tapped (1/4” NPT) one hole for the brass hose fitting and drilled the hole for the switch. I undersize punched holes in the rubber cap by sharpening a tube I had lying around that was the approximate size. I used all purpose between the rubber and aluminum cap holes and threaded the 5/16” brass fitting through the rubber cap and tight into the aluminum cap. I did the same with the switch, also using a gracious amount of the sealant around the switch. Once installed, I tightened the rubber boot over the throw of the switch.

All is done except for the wiring. I connected the light head to the canister with clear 5/16” tubing. I used clear so that I could see if it was taking on water. I ran the wire from light head to canister through the 5/16” clear tubing. I used 4 battery packs I already had, used in RC car hobbies.(They were there and so was the charger. There are better suited batteries out there.) Each pack was 1500mah so I wired in a series / parallel manner to achieve 6000mah. (set of two in series, then paralleling the sets of two).

I ran this setup last night with the 20W bulb to 50’ for 40 min. and it came out bone dry. I continued to run the light for an hour and it didn’t show signs of weakening. I plan on testing its longevity with the 20W & 50W bulbs. This project was interesting. I already have plans on improving a second version. I’ll post some pics when I get the chance.
 
I don't think I ever followed-up on my leaky canister... The culprit turned out to be the screws in the side. After several dives, I could see a stain coming from a few of the screws on the inside of the canister. I removed all of the screws & reinstalled them with plenty of RTV on the threads. For a while it was coming out dry as a bone, but now I'm starting to get a small amount of water, maybe 1/4 teaspoon. The next time I make a canister it will have 'regular' hose clamp attachments, instead of the strap held on with the stainless plates. That just added 10 more failure points, and some of them did leak.

The maglite lighthead has been pretty much trouble-free. I've only had water get in it twice. The big o-ring has to be sitting just right.



-Tiny-B.
 
Tiny Bubbles:
I don't think I ever followed-up on my leaky canister... The culprit turned out to be the screws in the side. After several dives, I could see a stain coming from a few of the screws on the inside of the canister. I removed all of the screws & reinstalled them with plenty of RTV on the threads. For a while it was coming out dry as a bone, but now I'm starting to get a small amount of water, maybe 1/4 teaspoon. The next time I make a canister it will have 'regular' hose clamp attachments, instead of the strap held on with the stainless plates. That just added 10 more failure points, and some of them did leak.-Tiny-B.

Try using some 5 minute epoxy on the screw threads instead of RTV. The epoxy is much harder and will stand up much better. The only downside to using the epoxy is that it's permanent and once installed it can not be removed. I know this because I tried to remove several screws from my old canister after installing them with the eopxy and twisted the heads off them in the process.
 
Tiny Bubbles:
I'm building another one this winter!

Here's a sneak peek...

-Tiny-B.

Tiny B., you need a third hand and a shop vac.! It's fun making all those shavings. I filled up a shop vac. with my dad over the holidays working on my DPV project.

How well does the adjustable circle cutter work on the drill press? Is that the one McMaster sells?

WD
 
I have a dive rite HID light that I want to make a goodman handle for, problem is after reading all of these DIY Canister light threads I didnt find much specific information on how to make a good handle. The information there is unspecific. Any one care to elaborate on how to make one?
 
puckvirus:
I have a dive rite HID light that I want to make a goodman handle for, problem is after reading all of these DIY Canister light threads I didnt find much specific information on how to make a good handle. The information there is unspecific. Any one care to elaborate on how to make one?

Puck, get a copy of Airspeed Press' book, The Dive Light Companion. Anybody with any interest in dive lights should have a copy. It's got several portions on light mounting and goodman type handle arrangements.

WD
 
Problem with this, I dont need to make an entire light, and considering other people around the board have made their goodman handles I figured someone could elaborate on its construction.
 
puckvirus:
Problem with this, I dont need to make an entire light, and considering other people around the board have made their goodman handles I figured someone could elaborate on its construction.

You can make one out of 1" wide x 1/8" thick aluminum that you can find at any hardware store in the metal/fastener aisle. Cut two pieces 7" long. Make a 90 degree bend on each piece, 2" in from the end. Take the two "L" shaped pieces and set them on top of each other like the Yin Yang symbol. Adjust the spacing in between them to accomodate your gloved hand and mark. Drill and SS bolt the overlapping short sections. For the light head holder, I used a 2" Schedule 40 PVC coupling. You have to cut a longitudinal section out of the coupling just large enough to allow the light head to snap into place. Drill and countersink the coupling to mount onto the handle with SS bolts. Don't forget to use a rattail file to remove the inner ridge inside the coupling to allow the light head to fully seat. I don't have any pics at the moment to post but will do that maybe tonight. Of course, there are an infinite amount of details that you can do to the arrangement to customize to your tastes.

WD
 
https://www.shearwater.com/products/perdix-ai/

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