Is there anywhere I can get another pill for a Convoy C8? The C8 style pills I have from other C8 type lights can’t be screwed on because of different threads. Is it possible to buy one somewhere without having to by a new host? My quick search revealed nothing, too bad Ryan is not making any more copper pills.
The gearbest should fit. Threads on the copper pills - really brass, but fit the convoy c8.
Is it this one you mean? http://www.gearbest.com/diy-parts-and-tools/pp_27445.html
As Gj writes, this is the kind that sits in other C8 style lights, like the UF-T20 I believe. They won’t screw into the Convoy C8 host, I’ve already tried.
Vesture of Blood copper pills are still available from E2FeildGear for $25 honestly tho for that price just buy a who XinTD host for $20 and be done with it. Sure you’ll have a left over host but you’ll get the better quality host and still save money. We all have parts drawers, sure it goes against our collective OCD to have an incomplete light but it’s the better route.
http://www.e2fieldgear.com/c8-t20-copper-pills-by-vesture-of-blood-for-flashlights/
Thanks everyone for letting me know.
What’s wrong with the original Convoy C8 pill?
Vesture of Blood copper pills appear to be for UF-T20. I have a UF-T20 and the pill does not screw on to the Convoy C8, which aslo makes we wonder about the pill Tom E suggested. It appears to be for the same lights. If I can’t find a Convoy pill I’ll just have to go with whats left of my original pill. Good tip with the XinTD host though. It might be on a future wish list if I want to build another thrower.
It’s not very pretty after applying a fare deal of violence to it to get an epoxy glued LED off 
I got a detailed post on the copper/brass pill. fits a convoy and UF C8. I'll link Later when home.
Edit: Post #78 here: https://budgetlightforum.com/t/-/26682
I'm pretty sure the GearBest and DealsMachine are the same exact pill. Think it's available other places as well.
Not too much, but it’s aluminium normally, which is lighter (a pro maybe) but not easy to solder and lower heat capacity per gramme than brass or copper.
Där ser man!
Thanks for the reference. I put in an order with DealsMachine.
I see. In that case I need some too :bigsmile:
Actually the specific heat of Al is more than twice that of Cu, 0.22Kcal/Kg-degC vs Cu at 0.092Kcal/Kg-degC.
Cu is over three times as dense, giving an identical part made of Cu a greater heat capacity overall.
http://www.engineeringtoolbox.com/specific-heat-metals-d_152.html
But here’s the thing, you don’t really want your pill to just suck up a lot of heat, infact doing so in a small body light is actually a bad thing. The HS won’t start to transfer its heat to the body till its heat soaked, if you have a copper HS that holds way more heat that means it’s not going to be transferring its heat out till its way warmer than with aluminum.
In a well finned super high power or multi-emitter light (or a hollow pill) yea you want to fill the pill with copper but in a small light with an already solid pill filling / converting with/to copper isn’t ideal. About the only advantage there would be so you can solder to the pill.
Aluminum is better at transferring heat to other substances (air, your hand, water), copper is better at retaining (and can hold more) heat and can transfer heat quicker to other copper but isn’t as good at passing it to other materials to actually shed heat to air (which is the end goal in a flashlight) just look at computer CPU heatsinks, if a solid chunk of copper was best that’s what they’d use, instead they use aluminum with as much surface area (fins) as can possible fit.
> Aluminum is better at transferring heat to other substances …
> copper … isn’t as good at passing it to other materials
Wait. I think what you’re talking about is emissivity, which is heat radiation.
There are discussions about this all over the Internets, endlessly repeating claims.
May I suggest citing sources? Here’s one test report:
http://powerelectronics.com/content/tests-compare-forced-convection-heat-transfer
So in a small light, alum pill with alum STAR screwed down tight should work best.
This is tricky. And the intended use is a factor. When is copper pad/pill better than alum ?
Umm - this is turning into the classic metal/heat discussion - been done many times here. There's lots of theory, but what do we know practically?
For Pills:
aluminum - you can't solder to it. Also there are lots of grades/alloy's out there, but usually in budget lights it could be the cheapest, worse kind. In budget lights, these type of pills are often made thinner, cheaper, and sometimes not machined well.
brass - great to solder to, and found more often in better, pricier lights. So what does the cost mean? A lot - more material, better machined, better alloy. P60 pills are almost all in brass, but this doesn't mean they are machined well (usually have a bump on the pill top for example).
copper - can be soldered to, but may be difficult at times (heat is drawn away so fast from the iron, it's hard to get the surface hot enough)
For Stars:
IMPORTANT:: presence of dielectric layer is more important than the material. Proven by djozz in actual LED STAR tests, dedicated thread
aluminum - you can buy these for 10-25 cents -- cheap. So usually a bad dielectric layer that you can't find a way of fixing. Typically thin.
brass - not used for STAR's - I've never seen one at least
copper - proven advantages over aluminum, well - are the advantages from no dielectric layer, or that they are usually thicker than aluminum ones? They do seem to have a slight advantage at high amps over aluminum in same dieelectric presence state. The dielectric layer can be manually removed, and solder in it's place - so it is fixable
I for one prefer more mass to the pill, but also want a strong bond to the outer shell of the light for an effective cooling path. Copper at the heat contact point, aluminum mass and surface area for the cooling, as strong a bond as possible between the two. Also, eliminate as much transition or transfer points (contacts, threads, etc.) as possible.
This doesn't mean the all aluminum Fenix lights don't have effective cooling. I believe the Fenix lights use copper stars, then it's aluminum from there - probably a good choice... They make a good argument for surface area over mass for cooling. For me, mass is much easier than surface area - I can't built new hosts with lots of fins that easy, for example. I don't have a lathe.
I think you have to be careful using a CPU heat sink as a role model. CPU's may run at full power continuously for months. A small high-power flashlight is typically run on high for a few minutes or less at a time. Having someplace to quickly dump heat during those few minutes for dissipation later when the FL is off or at a lower setting can be very helpful.
Of course, it depends enormously on the specific FL and intended use.
CK, I strongly disagree. I know this beating a dead horse, but it is what it is. Below is my previously posted argument on why.
"My position is that copper pills are better than aluminum.
Radiation heat transfer is a function of the difference in temperature to the 4th power. (Thot4-Tcold4)
Convective heat transfer is a function of the difference in temperature to the first power. (Thot-Tcold)
Both of them matter. Convection matters more to us than radiation due to the relatively low temperatures we operate our lights.
Why do I think copper is better? Inside the pill, whether it is aluminum or copper, there is a temperature gradient. It is hottest in the middle and coolest on the outside. It also varies over it's length in the same manner. Where copper outperforms aluminum is that the slope of this gradient is less since copper is about 89% better than aluminum at conducting heat. The outside temperature is closer to the inside temperature. (Luminarium observed that the pill gets hot quicker. I think this is commonly observed.) What this does, even if it is only a few degrees, is increase that temperature difference where heat is being exchanged (Thot-Tcold) at the body surface. That temperature difference is what drives the heat transfer. The larger the difference, the more heat is transferred. This is true of both radiation and convection. It is even applicable to conduction through the aluminum body of the light. So what this means is that for a given LED die temperature, the outside of the light will be hotter, thus convect and radiate more heat to it's surroundings. Stating it in another way, copper gets the heat to the outside quicker where a higher delta T transfers more heat away.
Secondly, barring any heat exchange at all, the copper pill is much more dense. For a given volume, it has roughly twice the heat capacity of aluminum. So for short term uses of a light, it will operate twice as long just using that copper as a heat reservoir than aluminum would. "