Convoy metal switch discussion

Difficult to say without examining it yourself to see the tolerances involved with the different moving part’s, but if you want to use a grease then:

If you have rubber with stainless a waterproof grease could be used, most greases are but some are better than other’s. One of the concerns with rubber is that a grease can change it’s mechanical properties causing it to swell and not function as designed.

There’re plenty of rubber seals on car’s where stainless is involved - caliper brake pistons are often stainless with rubber seals. A red rubber grease is used, Castrol CCG is one and it is water resistant. It’s based on vegetable oil and doesn’t harm rubber. It’s perfect for rubber to rubber and rubber to metal contact’s.

The grease viscosity will vary with temperature and you want it to remain in place in the switch and not to get it on your fingers, it’s perfect to use where you don’t have o rings and seals because of the low viscosity at room temperature.

Better than okay my friend. I was going to ask if you would do exactly that. It shows more of the switch internals than I’ve seen before with excellent pictures and descriptions. This will be helpful. Thanks! :bigsmile:

You don’t have any “brilliant” ideas. Ha! I suppose we actually are looking for a dim bulb here… “Why don’t you just ruminate, while I illuminate the possibilities”… Okay that’s all I have but it would be really cool if I could follow that with something smart. :stuck_out_tongue:

It definitely is hard even with good pictures to see the tolerances involved. I was hoping Simon could provide me with a CAD model but it seems he doesn’t have one for the switch. If it comes down to it I may just end up taking it apart myself to help me visualize possible solutions. I don’t really like the thought of relying just on grease for a few different reasons but all ideas and feedback are appreciated. :slight_smile:

FWIW, the first revision of the CNQG brass 18650 light has a waterproof metal button. Here’s how it goes together:





I tried a lighted tailcap in a blue S2+, and the light isn’t visible at all. The black rubber blocks it.

Thanks ToyKeeper! I meant to put in the OP that it would help if anyone could post pictures of properly waterproof metal switches from other lights. Excellent info and lots of pictures. Thank you. As far as the light up tailcap I’d think switching the black inner boot on the existing Convoy switch to one made of translucent silicone would be the easiest lighting option as long as Simon can have that sourced. I plan to ask. Do you think that would be enough to let a decent glow through? I know it’s not going to be bright like the silicone switch boots but based on the picture emarkd posted it might be visible enough.

It would seem I am out of my depth in this thread, and without a switch in hand it’s hard to be able to figure anything out, but it looks like that threaded section of the switch butts up against the lip of the rubber seal, if so what is on the other side of the rubber lip? Wouldn’t it just need a retaining ring or shelf in the switch housing for that lip to butt up against, and with the threaded section tightened down shouldn’t it be more than adequately waterproof?

I might just go back to making colour requests!

A thin rubber boot like the brass switch should do it.

No, I think you’re right and here’s the thing — there’s already a big metal washer in there that holds the top of the switch tight so that it keeps pressure on the retaining ring thereby making ground, just like about every other tailclicky light on the market. I think the rubber boot sits tightly against the top edge of that metal ring which, like you said, should make it quite waterproof.

I guess I’ll go ahead and ask: Are we sure its not waterproof already? I mean it looks like a solid design to me. Water will definitely get in around the nylon washer but should be stopped by that rubber boot I think, so shouldn’t do any damage. Has it been tested thoroughly as it is?

EDIT: Here’s a photo of the entire stack of stuff out of the tailcap of a Convoy S2+:

Do it. Test it.

If I had one I wouldn’t hesitate to dunk it a few times. What’s the worst that could happen? Fry a $3 driver? Even that won’t happen if you just leave the light off and check for dampness inside before using it again.

Yeah I don’t mind testing it. I’ve got four of these hosts, one of them doesn’t even have anything in it at the moment. I’ll get back to everyone with some findings later, hopefully this evening or tomorrow.

:star:

That pic of the stack helps a lot. If the washer seats firmly against the boot the weak point may be the threads. Perhaps a really low strength threadlocker would help?

Looking forward to the test results. For one of the tests would it be worth heating the light beforehand to create a pressure differential, and to simulate a light that’s being used on high being dropped into cold water?

I just got back to this and I love all the ideas, questions and concepts being thrown around. I honestly don’t have the time or brain capacity to put into it right now but I see intelligent people kicking this around and for that I say thank you! I am quite curious to see the results. I talked to Richard (RMM) a bit about this and he seemed to agree that most of the metal switches are more splash-proof than waterproof. I questioned this one myself as it’s the same switch used as a side switch on the BD01 which is shown here either giving false hope or proving that it IS indeed waterproof…

I look forward to hearing the results.

Ran two S2+ waterproofing tests tonight. For the first test I used a temperature differential as was suggested a couple of comments ago, but I did it the opposite direction. I chilled the light with the barrel open, then closed it while still inside the freezer. Now I’ve got a very cold light full of very cold air, which is dense. Then I dunked it into lukewarm water. The water warms the light causing the air inside to expand, forcing the air out of the weakest points. A good IPX8 light will barely bubble at all and will hold most of that pressure inside.

I found very little bubbling, much less than I expected to. One or two very tiny bubbles formed around the outside edge of the “sleeve” so there is some leakage around that oring. I think it could probably be greased and it would seal right up. I think we all know how important it is to keep orings greased and that one probably isn’t. Most of the leakage came from between the piston and the sleeve, so it was getting around that black rubber seal inside. I saw a bubble form and float up about once every 4 seconds, so not especially fast. Here’s a photo of how that looked:

Really this light leaked very little. I wouldn’t be afraid to get it quite wet, so that’s what I did next. For the next test I let the light come back up to room temperature, equal to the water. Then I just dropped it in the bowl and walked away. Its only a few inches deep, but I left it in for 15 minutes. After 15 minutes I retrieved it from the bowl. Inside the battery tube was completely dry. So I disassembled the switch assembly and it was completely dry too. ZERO water seeped past the black rubber seal during a 15 minute soak in a few inches of water. There was just a tiny drop or two above the black rubber so the nylon bushing by itself isn’t waterproof, but I don’t think we ever expected it to be.

I do have one thought about the air leakage I saw around that black rubber seal. I posted a photo earlier of the entire switch assembly stack from this light but it never occurred to be to look at how the head is machined. There’s a large shelf or “lip” inside the head that the silver washer sits on. That makes sense because it has to have something to put pressure against. I do see that the lip sits just a fraction of a mm lower than the rubber seal on the bottom of the “piston”. Not sure if you can see it in this photo, but it looks like this:

That means that the metal washer isn’t putting tight pressure on the bottom of the rubber seal, so I’m sure that’s where the highest potential for leakage is. If I were to make a suggestion to Simon it would be to machine just a bit more off of that shelf so that its completely flush with the rubber boot. I realize those are tight tolerances but for this design to seal up much more I think it would be necessary.

I’d like to take these tests a bit further and do some deeper water tests along with some jet spray/pressurized tests and see what happens, but not tonight. So far though, I’m really very impressed with Simon’s switch.

Or extend the edges of the rubber boot to overlap more of that edge and more of the washer, like TK’s pics

Good tests

I think the problem is that it might be technically waterproof but it’s relying on compression of a very tiny ledge to make the seal.

Hope you guys don’t mind me borrowing your pictures.

That’s what I think it really needs. The rubber gasket should extend to cover the whole surface there.

By the way, how is the rubber gasket attached to the metal button / “piston”?

I think that you guys are right: the very thin seal area is definitely a weak point, especially when dealing with mass produced parts and assembly processes that aren't perfect.

The solution would seem to be to make the rubber overlap more, and possibly machine the tailcap a bit differently if a switch change alone can't be made to work.