Nice Grunge Safety Mod to prevent a shrapnel explosion during catastrophic venting.

Databyter

Enlightened
Joined
Oct 12, 2005
Messages
525
Location
San Diego
I mostly use NiMh but if I did use multiple Li Ions I would consider the following grunge mod to allow daily micro venting, and emergency catastrophic venting without explosion in your Li Ion light.

Drill a small hole in the tail (or other hidden less visable area contiguous to the batt. compartment such as fin grooves etc.). By small I mean like 3/32nds to an 1/8 inch. This hole size is estimated by me to be about right for a 2-3 D size handheld, go smaller for small edc's (like 1/32 and no pinhole as described later, unless you can find a pin thin enough). For really large compartments use a screen material for support.

Fill in the hole with clear silicone sealant (color to match if you like, Use dry material to color i.e. graphite for black etc. Also you can buy it colored for some applications I believe). Make sure to put enough material on the inside of the hole, you can smear a thin layer about a half inch wide on the inside surface, and a bit more in the center provided there is room and it won't interfere with loading batts. Use 100% silicone sealant, or aquarium sealant, not a silicone caulking hybrid mix.

When it is dry use a very thin pin to carefully and slowly poke a hole through the center of the plug. Use a high quality lube or grease on a very sharp THIN pin for this. Most pins are not sharp, just small, so sharpen as needed for a nice clean hole without popping the plug to make it. Support the inside as you do this by pressing hard with a piece of potato or something else firm but pokable. Go all the way through.

This will stay water resistant because the plasticity of the silicone will virtually reseal the pinhole. Any added grease left in the hole is a plus (use a synthetic lubricant iif possible so it doesn't break down the silicone).

During normal venting, or even screwing on a long threaded head positive pressure will be vented out but rain will not go in.

During explosive venting the plug will pop out completely or bulge if you are using the light so you can pull it out (or drop and run depending on the pack and size of light).

I thought this up when reading the TK Monster thread about an explosive venting, (not caused by the TK Monster).

I was thinking about solutions for large lights that would preclude paying alot of money for an ugly micro venting valve or redesign.

I like this because it's almost free cheap, can be redone if it's damaged, should be water resistant, and has both daily micro venting and explosive venting relief capability.

Nice grunge "safety mod". And although it's a grunge for sure, if done properly and with skill can be relatively un-noticable for all practical purposes.

I have never used this method, it's all just in my head. If someone tries it pls let us know how it looks and works.

You can experiment with finish by applying a bit of nail polish or something even better you may think of while the pin is still inserted, twist the lubed pin slowly so the hole is preserved as the fast drying smooth surface dries. It might make the soft silicone stay cleaner and less grabby.

Use your light with more confidence that the constant micro venting that will occur will keep the more rapid emergency venting started at much lower inside pressures, and the safety plug will allow fairly rapid venting when it pops our or is pushed to open.

Keep in mind that if you have an explosive venting using this method, it is still dangerous of course, just doesn't have the same explosive potential. Think of hearing a sound like an approaching jet engine or freight train colliding with a giant popcorn machine as your light takes off across the floor like a rocket propelled rc racer, or it just might spin rapidly burning a nice hole in your carpet or car seat. All depending on where the hole is, how big it is, and how serious the venting is.

This might even start a new sport.

Think of this at the next CPF gathering, a roped off area where forum members can have Li Ion powered mag distance contests (kidding of course).

Another consideration is that as single batteries swell in a tight tube they might cut off the gas flow to the area the vent is by self sealing themselves.
Snug batteries in a tight tube is a no no for this plan if they are singles in a single tube with no ridges or gaps for gas to move through. It might still help though. Multi cell wide is better for this, or a looser tube, or a tube with interior grooves for gas.
 
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csa

Enlightened
Joined
Feb 15, 2010
Messages
281
I doubt that this method is really going to contain explosive venting, but since that doesn't happen with any particular frequency in real life, it's fine...
 

kaichu dento

Flashaholic
Joined
Apr 5, 2008
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Location
現在の世界
I think it might work to avoid explosive venting too, as the pressure doesn't just build suddenly, and if the pressure was being let out then it would not reach high enough pressures to allow an explosion.

Very interesting idea and the more explosions I read about the more enticing it becomes to give it a try.
 

Ken_McE

Flashlight Enthusiast
Joined
Jun 16, 2003
Messages
1,687
Well thought out. Maybe you could sell tailcaps that have this mod. Quick, go file a patent.
 
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