My first canister light project.

[ktomlinson]

I just finished assembling my first canister light. I haven't tried it underwater yet, but feel pretty confident about it. I still have to make a handle and attach the canister to my harness, and it still looks pretty rough on the outside because I haven't painted it yet, but I wanted to go ahead and put together a small thread about the parts I used, and what I learned. At the end of this thread, I have put together a list of where I bought parts, and how much they cost. Thank you to 350xfire for getting me started with advice and o-rings and a lens.

I built my light head with a D cell mag light. I am in the process of building another light head for my wife, and I am using a C cell mag light. I like the C cell better than the D cell because you do not have to cut out part of the light head like you have to with the D cell to get the reflector to fit. The only draw back with the C cell is that you will need to fill the tailcap with jbweld, or actually weld in extra aluminum so that you can tap it and have enough aluminum for the threads on the cable glad to grab, but that really isn’t a big deal. I recommend welding or jb welding the tailcap onto the main body tube of the light head because you really don’t need to remove it in the future and this eliminates one more potential leak.

There are really just a few steps to making a light head using the C cell mag light. You need to cut the body down to a length you are comfortable with, and jbweld or weld it to the head. Fill the inside of the tail cap with jbweld and let sit over night. Tap the tailcap with a ¾” fine thread tap and then jbweld the tailcap to the main body tube. Get a slightly larger o-ring (I have ordered multiple sizes of o-rings, and when I get them and determine the appropriate sizes, I will post them) than the mag light comes with for between the front of the lens and the crown and another for the outside of the head under the crown. You will also need to buy a thicker glass lens (like the one from DealExtreme). The reflector/led combo that I have listed is nice because it fits in the mag light with just a slight modification (you have to cut a couple of millimeters off of the reflector so that that the o-ring on the outside of the head seals), and the LED screws on the bottom of the reflector so you don’t have to worry about mounting it.

To assemble the canister I used tamiya connectors from a hobby store, a remote control truck battery, and a switch from Dive Gear Express. I wired my canister so that the battery connects to the canister and then the canister connects to the lid.
Overall this was a really fun project. My first test dive should be tomorrow, hopefully it stays dry! One last tip, I struggled to get the strain reliefs on the cable glands over the cable until I discovered 3 in 1 oil.




SSC P7-C 2800mA LED Module with Copper Base (3.6V~8.4V) $23.30
Glass lens
Type SJOOW, 2 Conductor, 16 AWG (Home Depot) 5 foot ~$5.00
DR-LT6096 Toggle Switch, enviromental sealed $12.95
DR-LT6092 Switch Boot $6.37
DR-LT6017SRG Sealing Gland w/Strain Relief In S $16 x2 (tap with 3/4" fine thread tap)
OMS 660' Depth Rated Canister, Clear (BCA-298) $39.95
Orings
7.2v 5000mah battery ~$40
Mag Light (Wal-Mart, Amazon)~$20-25
Tamiya connectors (Hobby Store) -$2
Total (with shipping) ~$210

 

[350xfire]

Hey man:
Glad to see you got it done. A few pieces of advice:
1. Do not use those lenses... While they will handle some pressure, the SLIGHTEST hit will crack them. I hate for you to have spent so much time and effort building this thing and have it flood because of a crappy lens! Now, tlslights.com (my site, haha) sells a 5mm custom borosilicate glass lens that has been to 265' in a pressure pot for 2days without problems. BTW, I speak on the DX lenses from experience, not trying to just sell you something.

2. All you had to do was go to tlslights.com and you would have seen a Mag kit with the proper orings! No trial and error here, just the right stuff! haha

3. OK, I won't mention tlslights.com on this one... Wait, I already did... lol! On the tailcap gland, yes, the mag C tailcap is thinner and the gland will go in too far into the area where there are no threads so it spins freely. Being a hater of JB Weld, I came up with a solution. Just put a bigger oring on the gland and now it does not go in all the way so it tightens up against the tail cap. Works well and no JB Weld.

4. For goodman handle, you can use a hard goodman handle with holes drilled and tapped to use the Maglite Auto clamps. Let me know if you need help from tlslights.com on this...

5. May want to consider a switch guard to prevent the boot from getting torn! Yes, I can help with that as well!

Good luck with it!

Hector

 

[ktomlinson]

Hector, thanks again for the advice! The lens I am using on the d cell is the one I got from you, I will be ordering a lens from you for my wifes c cell now I didn't know you had a website now, that's great! I will be checking it out today, and probably ordering some stuff too. On the c cell tailcap I just added extra aluminum, but I proposed jbweld in the post because I didn't figure everyone has access to a tig welder. I tried an extra oring temporarily and it worked but I wanted to go with more grip

 

[350xfire]

Hector, thanks again for the advice! The lens I am using on the d cell is the one I got from you, I will be ordering a lens from you for my wifes c cell now I didn't know you had a website now, that's great! I will be checking it out today, and probably ordering some stuff too. On the c cell tailcap I just added extra aluminum, but I proposed jbweld in the post because I didn't figure everyone has access to a tig welder. I tried an extra oring temporarily and it worked but I wanted to go with more grip

OK, cool man. Good work. Just really be careful with those thin lenses. Any small strike and they will crack!
Oh, and the site just got launched about a week ago. Had a customer build it for me.

 

[ktomlinson]

Well I just got out of orange sink and have to go back to the drawing board...flood! Both the canister and the light head flooded. I think they flooded at the cable glands. Maybe my next project should be a pressure pot!

 

[350xfire]

Well I just got out of orange sink and have to go back to the drawing board...flood! Both the canister and the light head flooded. I think they flooded at the cable glands. Maybe my next project should be a pressure pot!

The wonders of DIY... Keep going and don't get frustrated with it yet! You'll figure it out. I've had a few floods along the way.

I have often found that if you let the light sit in a bucket of water overnight and it stays dry, then it will probably be OK at depth... No guarantees, but probably.

Did I mention... well you know who has all the proper stuff for this build right? lol

Looks like your cable glands are tightened up around the cable well. If you tightened them on the can lid and Mag I don't see how those could be the problem. How long was your dive? Were both parts totally flooded? Did you make sure the switch boot was fully seated? Sure it wasn't a lens leak? Did you use anything other than orings to seal around the lens?

Hector

 

[350xfire]

I just asked you to be my friend... Hope that makes you feel better!

 

[ktomlinson]

I'm not really frustrated, but I do appreciate the friend request! I actually looked at the cable glands this morning and thought "I should tighten those down more (talking about the two nuts on the cable gland, not where the cable gland screws into the light head or canister)" but didn't because I didn't have a thin enough wrench to get a good grip on the bottom nut. The flood was minor, and the light still worked with it flooded, but I thumbed the dive. The light was submerged for about 15 minutes. I let everything air dry this afternoon, and then sprayed out the switch with an air compressor. I just got back from reassembling everything. The cable glands are fully tightened now, and I have siliconed the one on the canister in, and jbwelded the one on the tailcap in. I am just happy that even though it flooded all of the components are still working!

 

[350xfire]

I'm not really frustrated, but I do appreciate the friend request! I actually looked at the cable glands this morning and thought "I should tighten those down more (talking about the two nuts on the cable gland, not where the cable gland screws into the light head or canister)" but didn't because I didn't have a thin enough wrench to get a good grip on the bottom nut. The flood was minor, and the light still worked with it flooded, but I thumbed the dive. The light was submerged for about 15 minutes. I let everything air dry this afternoon, and then sprayed out the switch with an air compressor. I just got back from reassembling everything. The cable glands are fully tightened now, and I have siliconed the one on the canister in, and jbwelded the one on the tailcap in. I am just happy that even though it flooded all of the components are still working!

OK, hope that works... It should not take them to be fully tightened to seal though. On your pics, they looked pretty tight. I usually end up with about 1/16" gap or so. Sometimes I can get them all the way down but not often.
And yes, a bit of silicone does not hurt. However, be careful when putting silicone on the canister end as it lubricates the gland really nicely and you can strip the threads off the PVC easily... Well, not really easily but easier than if you did not put silicone. Also, try to find some non-corrosive silicone if you are going to use them on final assembled parts like a heas where there is no ventillation. The solvents used in auto parts store silicone can tear up electronics and LEDs since they are corrosive. Typicalle at auto parts they have a black high temp silicone that is not corrosive or much less than the clear or cblue. Rule of thumb, if it smells like vinegar, don't use it. Now on a can where you can leave it open to dissipate the fumes it may be OK.

 

[ktomlinson]

Thanks a lot Hector. I checked out your website, and like it! Is that light head in your banner picture (the one with the aspheric lens) something you are experimenting with?