DIY 35W Canister Light

[Padipro]

Did you get your stress relievers from McMaster? I was looking for those and couldn't find a place on line that actually "sold" them and I couldn't find them on McMaster.

I got them from a company called Seal Con USA. So far they've worked perfect.

If your light head has an added O-ring sitting on top of the bulb and then the glass lens on top of that I'd advise against diving with it. This was the original design for sealing the light head but we found out quickly that the edge of the bulb doen't take the pressure very well and will crack. Once it's cracked the light head will flood. I waisted several bulb connections trying to fix this problem but it was Andy, a member of my DIY site, that came up with the idea of adding a plastic ring to the lens which holds the added O-ring in place to seal against the outter edge of the Mag-Lite reflector housing. That evolved into the stepped lens which is what most people are using now.

 

[dsater]

I waisted several bulb connections trying to fix this problem but it was Andy, a member of my DIY site, that came up with the idea of adding a plastic ring to the lens which holds the added O-ring in place to seal against the outter edge of the Mag-Lite reflector housing. That evolved into the stepped lens which is what most people are using now.

Thanks for the input. Better to know now. According to your site it sounds like you can create the stepped lens with a drill press and the correct bit and perhaps some kind of jig for a smooth circular cut. Where did you get the thermo plastic lens?

 

[jpsexton]

What about this design? It's what I was thinking of using.

http://groups.msn.com/Divelight/canisterlightezlighthead.msnw?action=ShowPhoto&PhotoID=1020

 

[Padipro]

The lenses are easy to make, in fact I made two this afternoon in about an hour using a hand saw to rough cut the lens out of a sheet of plastic, a disk sander on my table saw to sand them down to fit into the retaining ring of the Mag-Lite and then a router with a rabbit bit to cut the step. You can use the original glass or plastic lens to draw out the circle and then cut and sand it to fit, no special jig needed. You can use a drill press and a rotory file to cut the step if you don't have a router.

I got the plastic I used from a local plastics dealer. I was looking for some 1 inch thick stuff for one of my older camera housings and asked if they had any scraps which they gladly sold me cheaper then if they had to cut the stuff from a new sheet.

 

[Padipro]

What about this design? It's what I was thinking of using.

http://groups.msn.com/Divelight/canisterlightezlighthead.msnw?action=ShowPhoto&PhotoID=1020

NO, that's the original design I was talking about. The O-ring sits directly on the bulb and the water pressure will crack the edge and the light head will flood. The stepped lens works perfectly and will keep the light head from flooding.

 

[jpsexton]

NO, that's the original design I was talking about. The O-ring sits directly on the bulb and the water pressure will crack the edge and the light head will flood. The stepped lens works perfectly and will keep the light head from flooding.

I don't think thats what this guy is doing. From this sketch it looks like the lens is resting on the rim of the head. I believe he is just replacing the stock o-rings with thicker ones and boring out the heat for the bulb to recess into.

http://groups.msn.com/Divelight/canisterlightezlighthead.msnw?action=ShowPhoto&PhotoID=1033

 

[Padipro]

I don't think thats what this guy is doing. From this sketch it looks like the lens is resting on the rim of the head. I believe he is just replacing the stock o-rings with thicker ones and boring out the heat for the bulb to recess into.

http://groups.msn.com/Divelight/canisterlightezlighthead.msnw?action=ShowPhoto&PhotoID=1033

I see now what he's trying to do. By increasing the size of the 2 O-rings he's sealing the light with both of them and not adding a seperate O-ring and a stepped lens. I've never tried this approach but I guess this would work, he says it does. My only concern is the strength of the glass lens, this is one reason I changed to the stepped lens. I first used Andy's design of the plastic ring to hold the O-ring on the edge of the refelector housing. It worked for the first 140 feet of the dive but at 145 feet the glass lens imploded.

Imploded lens

The glass seems to be strong enough for dives to recreational depths but if you ever plan on taking it any deeper you should install a stronger lens, one made either of thicker plastic or glass. Some folks are using two glass lenses, one a slightly smaller diameter then the other glued together to form the step instead of making a solid stepped lens out of plastic like I do. Either way it seems to work.

This is why I love doing this DIY stuff so much. I love watching the way people solve the problems. I came up with the idea of cutting the Mag-Lite to remove the switch hole and then removing the threads to incert the battery tube into the housing but I couldn't figure out how to seal the lens. Another guy figured out how to add the O-ring in the original design but this didn't work at deeper depths. Andy then came up with adding the plastic ring to hold the O-ring on the edge of the housing but the glass lens wasn't strong enough to take the pressure of really deep dives. Then someone else came up with the idea of the stepped lens which solved both problems. It just keeps going and going with still others coming up with even easier and slimpler ideas of solving the some of the same peoblems. It's great.

 

[jpsexton]

I'll never be diving deeper than recreational depths so I don't have to worry about implosion I may still make a stepped lens though it looks like it may seal better. I've got a full machine shop at work to use so it would'nt be hard to make. I guess I'll decide once I get started putting things together.

PS: Thanks for putting up the divelight sight, its a wealth of information!

 

[MilitantMedic]

If you've got a machine shop, why not put it to good use? There are some nice CAD plans lying around....machine us some nice AL heads!!

 

[jpsexton]

I had thought about making something from scratch but the cost of a maglite verses the raw material is much cheaper. It's still a thought though, where did you see those plans?