How to heat-sink drivers?

I can not think of any cheap and easy ways to heat sink some P7 buck drivers in a Mag.

Any suggestions? Gluing them to the emitter heatsink is not going to work.

I like the slugs that I have seen some people use that look kind of like a half mood woodruff key that is glued to the body of the Mag, then the driver glued to that. Where can I buy something like that?

I just ordered something like this:
http://www.amazon.com/dp/B001DU7DPQ/?tag=cpf0b6-20

I probably won't glue these to the Mag body, since I still want to be able to remove the parts, but using something like this with the driver glued to it will still be better than most other things.

Drewfus2101 said:

I can not think of any cheap and easy ways to heat sink some P7 buck drivers in a Mag.

Any suggestions? Gluing them to the emitter heatsink is not going to work.

I like the slugs that I have seen some people use that look kind of like a half mood woodruff key that is glued to the body of the Mag, then the driver glued to that. Where can I buy something like that?

Click to expand...

You are talking about the Shark Sinks that Led Zep makes for the Shoppe.

I have also seen some good heatsinks made from a copper pipe. The pipe fits inside the Mag, and tabs are bent from the pipe to glue or solder the drivers onto. You can do something similar with a few tabs bent downward at an angle.

http://theledguy.chainreactionweb.com/product_info.php?cPath=48_56_103&products_id=1163

I potted mine in thermally-conductive epoxy. Just for yucks, I put an aluminum disk above and below the driver. The inside diameter of a PVC cap (don't know what size) is just a little bit smaller than a D cell. I drilled two small holes in it that just matched the OD of the wires and pulled the wires through, then filled it with epoxy. Pour slowly and at a high angle initially to minimize bubbles. I always use a vacuum chamber to get rid of any leftover bubbles--probably overkill.

Worked like a champ. The Kai three-mode driver overheated in 30 seconds before, now it'll run the batts dry--6 Nimh or 2 LiIon without the thermal gizmo kicking in.

LED Boatguy said:

I potted mine in thermally-conductive epoxy. Just for overkill, I put an aluminum disk above and below the driver. The inside diameter of a PVC cap (don't know what size) is just a little bit smaller than a D cell.

Worked like a champ. The Kai three-mode overheated in 30 seconds before, now it'll run the batts dry--6 Nimh or 2 LiIon.

Click to expand...

potting entire drivers in epoxy also has other advantages
reinforcing components, particularly the inductor from damage from impact
Insulating all open contacts from dust or anything that may be conductive and within proximity of those contacts

But the issue with that is any future modifications of the drivers require unpotting and it can be difficult for small drivers

Illum_the_nation said:

potting entire drivers in epoxy also has other advantages
reinforcing components, particularly the inductor from damage from impact
Insulating all open contacts from dust or anything that may be conductive and within proximity of those contacts

But the issue with that is any future modifications of the drivers require unpotting and it can be difficult for small drivers

Click to expand...

There's no such thing as unpotting . I do it on most of my (real job) stuff so it'll be harder to reverse engineer--and for heat sometimes.

I consider the driver a throwaway item. Hell, it was unusable as it was. Now, it's a black cylinder with two wires coming in and two going out. Come time to upgrade--snip snip, and I'm ready for the next one.

One small problem with potting--though I have not seen it yet. While MG Chemical's thermo epoxy is non-conductive, it can be slightly capacitive and they say it can cause gremlins in some hi-freq applications.

PS I bet potting would stop that PWM noise too. A lot of that noise is from loose coils on the inductors.

along these lines, what kind of material is used to pot pills? I'm looking for something that dries even and smooth similar to what you see in Malkoff's pills. Thanks

LED Boatguy said:

One small problem with potting--though I have not seen it yet. While MG Chemical's thermo epoxy is non-conductive, it can be slightly capacitive and they say it can cause gremlins in some hi-freq applications.

Click to expand...

hmm, I didn't think of that:shakehead

Casebrius, depending on the application in mind areas of the driver where heat may be come a problem may be potted with Arctic Alumina while other areas with passive components such as capacitors and inductors may be potted with regular epoxy...like pills, for example.

LED Boatguy said:

I potted mine in thermally-conductive epoxy. Just for yucks, I put an aluminum disk above and below the driver. The inside diameter of a PVC cap (don't know what size) is just a little bit smaller than a D cell. I drilled two small holes in it that just matched the OD of the wires and pulled the wires through, then filled it with epoxy. Pour slowly and at a high angle initially to minimize bubbles. I always use a vacuum chamber to get rid of any leftover bubbles--probably overkill.

Worked like a champ. The Kai three-mode driver overheated in 30 seconds before, now it'll run the batts dry--6 Nimh or 2 LiIon without the thermal gizmo kicking in.

Click to expand...

I would also suggest using a copper cap instead for any higher power mods since pvc is a thermal insulator and copper is very easy to work with.