diy dive light canister, less expensive option

[martzak]

I'm in the process of building a 'non-tech' canister dive light and one of the main challenges was finding an appropriate waterproof canister without spending an arm and a leg. I finally decided on the otterbox, in this case Otterbox 8000 series. The box comes with a neoprene gasket rated to ~100ft. Since I'm not a technical diver, I only wanted to extend the depth rating to ~200ft.
So, to beef up the gasket I laid down a layer of RTV silicone gasket on top of neoprene seal and made it flush with the edge of the lid (no excess rtv bulging from the gasket channel). Let it set for 24 hrs.
I recently tested the canister down to 175ft in 38F water. No leaks.
I realize this is a far-cry from exhaustive pressure testing, but at least it shows that it's possible to easily reinforce the otterbox gasket to withstand greater depths. By the way, the otterbox is being touted as 'crush-proof', so the only weak point is the gasket.
I'm creating this post for those that may be interested in building a low cost, non-technical canister dive light.
The next step will be to run a cable from the canister to the light head, spider light with seoul SSC P7 LED.
I'm willing to share all of the details and pictures with anyone interested in this.

 

[reefduffer]

You should read this recent post:
http://www.scubaboard.com/forums/making-your-own-gear/279489-otterbox-depth-testing.html
if you haven't already. And maybe you guys should talk.

 

[martzak]

reefduffer, Thanks for the link. The pressure test results for otterbox 9000 don't look very promising for my dive light. I'm hoping that because otterbox 8000 is shorter and stubbier it will withstand higher pressures before being crushed. Because I do not have a pressure chamber to test this in, I will have to lower my otterbox into a deep quarry for my final depth test. I will also contact Otterbox to see if they can offer any information regarding crush pressure for the box itself.

 

[350xfire]

I'm in the process of building a 'non-tech' canister dive light and one of the main challenges was finding an appropriate waterproof canister without spending an arm and a leg. I finally decided on the otterbox, in this case Otterbox 8000 series. The box comes with a neoprene gasket rated to ~100ft. Since I'm not a technical diver, I only wanted to extend the depth rating to ~200ft.
So, to beef up the gasket I laid down a layer of RTV silicone gasket on top of neoprene seal and made it flush with the edge of the lid (no excess rtv bulging from the gasket channel). Let it set for 24 hrs.
I recently tested the canister down to 175ft in 38F water. No leaks.
I realize this is a far-cry from exhaustive pressure testing, but at least it shows that it's possible to easily reinforce the otterbox gasket to withstand greater depths. By the way, the otterbox is being touted as 'crush-proof', so the only weak point is the gasket.
I'm creating this post for those that may be interested in building a low cost, non-technical canister dive light.
The next step will be to run a cable from the canister to the light head, spider light with seoul SSC P7 LED.
I'm willing to share all of the details and pictures with anyone interested in this.

What kind of battery pack are you going to use?

 

[martzak]

What kind of battery pack are you going to use?

Right now I have a Sealed Lead Acid battery, 6V 4500mAh, that fits perfectly into the container. I haven't tested it yet, but I calculated ~1hr of run time at ~3A draw. In the future, depending on the results, I may go with 18650 Li Ion batteries.

 

[martzak]

You should read this recent post:
http://www.scubaboard.com/forums/making-your-own-gear/279489-otterbox-depth-testing.html
if you haven't already. And maybe you guys should talk.

It appears that the failure occurred at the gasket channel/lip, so perhaps reinforcing it from inside with some type of a cross-member brace could strengthen this part of the box. Just a thought.

 

[martzak]

Quick update to the otterbox dive light test.
I sent an email to Otterbox with test results from:

http://www.scubaboard.com/forums/making-your-own-gear/279489-otterbox-depth-testing.html

This is the response I got:

"Thank you for that information! I would suggest that those seem to be very solid guidelines for the structural integrity of the case. I was told that we had done similar testing with regards to pressure exerted with different depths and found that similarly, the case did implode when it finally did fail, but unfortunately we do not have any of the data for those tests available.

I would recommend keeping the box completely sealed above that first marker (70 PSI, 160 ft fresh water, 155 ft salt water) where there was bowing; any force that would cause our case to bow like that would compromise any and all seals keeping the device enclosed.

I hope this helped, and apologize that I am unable to provide any more information..."

So there you have it, even with a reinforced seal/gasket you want to keep your otterbox above 155ft sw.

 

[350xfire]

Doesn't get any cheaper than a piece of PVC pipe!

 

[martzak]

True, but you need equipment to machine the lid and pipe mating surfaces to a pretty smooth finish in order for a tight sealing. Any ideas on how to do that without the need for high precision equipment?
I tried the PVC pipe approach first and had a really hard time getting the lid and pipe surfaces to line up 'perfectly'...I used a dremel and sand paper, not very precise.

 

[Packhorse]

True, but you need equipment to machine the lid and pipe mating surfaces to a pretty smooth finish in order for a tight sealing. Any ideas on how to do that without the need for high precision equipment?

Its surprisingly easy. Get a piece of A4 paper and wrap it around your pipe. Line the paper up so the edges meet. This will give you a true line to cut. Mark with a pencil or marker. Remove paper and cut on the line with a hacksaw. Rotate the pipe as you cut into it. The result will be a pipe with a end that has a good right angle to it. Next lay a piece of sand paper on a smooth flat surface and hold the pipe end against it flat and move backwards and forwards rotaing it every few strokes. You will soon end up with a nice flat level surface.