# DIY Maxflex Heatsink - Now for All Circuit Boards?



## SnowplowTortoise (Mar 16, 2008)

I think I came up with a new and relatively easy way to provide good heat sinking for the MaxFlex circuit board. I’ve seen some very tidy solutions where the board is connected to the underside of the heatsink, but I would rather not connect the only two hot things in the light.

So for my “SinkaFlex”, all you need is a 35¢ copper coupler for 3/4” diameter copper tubing. A little filing here and there, some sanding, a quick bend, some Arctic Silver, and you’re ready roll. By cutting the coupler open and expanding the diameter a bit, you can get it to spring into a nice tight fit inside the body and still take it out if required. The copper itself is not too thick, but excessive mass only helps you in dynamic conditions. Surface area is the name of the game for steady-state, and this one has plenty, I hope... 

Thanks for looking!


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## Supernam (Mar 16, 2008)

*Re: DIY Maxflex Heatsink*

Awesome. Great idea. I was thinking of something similar using copper pipe, but yours looks way cleaner and effective.


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## traildesaster (Mar 17, 2008)

*Re: DIY Maxflex Heatsink*

When I use the maxflex2 I can dim the LEDs down when thei're getting to hot, so connecting the maxflex directly to the heatsink is very smart!

Gruß td


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## SnowplowTortoise (Mar 17, 2008)

*Re: DIY Maxflex Heatsink*

Thanks Supernam - glad it was useful.

TD, George does not recommend sinking the board to the LED heat sink. He explains in the following threads that there is usually a dependable correlation between the temperature of the air within the housing and the temperature of the LEDs:

www.candlepowerforums.com/vb/showthread.php?t=179136
www.candlepowerforums.com/vb/showthread.php?t=181420

Your thermal monitoring is certainly more accurate, but for my project, I would rather have adequate monitoring and, instead, optimize the heat transfer paths. Better to keep things cool than to accurately measure them getting hot!


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## datiLED (Mar 17, 2008)

*Re: DIY Maxflex Heatsink*

Very nice work. That is creative, and looks like it will be effective. :thumbsup:


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## Aircraft800 (Mar 18, 2008)

*Re: DIY Maxflex Heatsink*

*Very Nice Sink! I used an Idea I got from member Download and came up with this MaxFlex sink:* 






*Another DIY*


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## SnowplowTortoise (Mar 18, 2008)

*Re: DIY Maxflex Heatsink*

Thanks datiLED.

Aircraft800, that's a nice solution too. I saw your post about it and probably would have done exactly the same if I could have found a local source for copper stock. Necessity really is the mother of invention! My version is maybe a little simpler to craft and uses more readily available materials, but I like how yours results in a one-piece switch-circuit board and wire lengths are minimized. All good stuff.

BTW, what is that blue thing bridging across the big black thing (sorry) on your Maxflex? Mine doesn't have that. Thanks!


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## Sway (Mar 18, 2008)

*Re: DIY Maxflex Heatsink*

Wonderful idea! I will try this on my next build.


Thanks!

Kelly


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## Aircraft800 (Mar 18, 2008)

*Re: DIY Maxflex Heatsink*



SnowplowTortoise said:


> Thanks datiLED.
> 
> Aircraft800, that's a nice solution too. I saw your post about it and probably would have done exactly the same if I could have found a local source for copper stock. Necessity really is the mother of invention! My version is maybe a little simpler to craft and uses more readily available materials, but I like how yours results in a one-piece switch-circuit board and wire lengths are minimized. All good stuff.
> 
> BTW, what is that blue thing bridging across the big black thing (sorry) on your Maxflex? Mine doesn't have that. Thanks!


 
*It's a capacitor George added.*

*There was a problem with the Original maxFlex v1.0 Drivers. George worked out the problem and began selling the updated maxFlex (I believe it was called the v1.2). Now the maxFlex v2 are out and were redesigned. Here is the original thread:*



georges80 said:


> I've had a few requests by folk that want to rework their own maxFlex boards.
> 
> Below is a picture of the rework. Basically remove C7. Then solder a radial leaded capacitor (1uF/16V X7R).
> 
> ...


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## SnowplowTortoise (Mar 23, 2008)

*Re: DIY Maxflex Heatsink*

Thanks for the info Aircraft800. I guess I don’t have to worry about that as my board appears to be from the newer batch.

So I tried the heatsink design out on another circuit board. The one in the photos is one of the generic AMC 7135 1050mA boards from DX. It gets very hot on high and would definitely self-destruct without heat sinking. This time I reduced a 1” copper coupler to fit instead of increasing a 3/4” coupler. I think the copper is a little thicker on the 1” tubing, but I don’t think it matters much which one you use. I also discovered that you can do most of the shaping with a pair of tin snips because the metal is so soft. That saved me a lot of filing and sanding.

So as you can see in the photos, it seems like you could make this sort of thing work for pretty much any circuit board – as long as you can figure out how to connect all of the wires to one side.

Just out of curiosity, I turned the light on for a few minutes while disassembled (as it was in the first two photos). After a couple of minutes, the circuit board heatsink seemed just as hot to the touch as the LED heatsink, which reinforced my belief that it is worth the added effort to keep the two heat generating parts as far apart as possible.

Thanks again for looking!:wave:


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## Supernam (Mar 23, 2008)

Snowplow,

I just made my first heatsink today similar to yours except for a D mag. It has a bent tab just like the first one you made, but then I epoxied a flattened penny to it to make a bigger platform. 

I had a hell of a time cutting and bending it though. The 1" coupling is way thicker than the 3/4". It was also hard to expand it while contouring it to the inside of the tube.


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## Aircraft800 (Mar 23, 2008)

Great Job with the heatsincs! Copper works very well to disipate heat, and since you can form it and cut it with tin smips, file and a hammer makes it a great material for anyone without fancy tools.

Are you starting with just a 3/4 union (for connecting 2 pipes), or a cap? What is the thickest that you can cut with a tin snips? Maybe for your next buils show a step-by-step.

:thumbsup:


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## LED Zeppelin (Mar 24, 2008)

Ingenious ideas Snowplow and Aircraft. :goodjob:


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## dat2zip (Mar 24, 2008)

Wow that looks nice. Good job.:thumbsup: I like the idea. That gives me a couple of ideas that I would like to explore as well as test your heat sink on the Shark.

Thanks for sharing.

Wayne


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## X_Marine (Mar 24, 2008)

Great means of devising a very effective heat-sink.

Thanks for sharing. I'm sure we will see many variations in the future.
Copper like aluminum is a pleasure to work with and has the added benefits of allowing us to solder it also.

I remember a technique from a hundred yrs ago of heating copper washers that were used as solvent resistant seals and other gaskets on cycles etc. the name escapes me, Ah Google to the rescue, annealing, but the purpose was after being under pressure it becomes harder and may not reseal when used in such cases. But simply heating over and ovens open flame would allow the copper to soften back up and ensured a good seal.
http://www.finishing.com/251/47.shtml

I only mention this because after forming and pounding it may also loose some of it's dissipating properties and the process may help. May be just the opposite as well, but the thought came to mind and had share.

Sry for the rambling.. lol

Thanks
X/BillyD..


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## SnowplowTortoise (Mar 24, 2008)

Aircraft800 said:


> Are you starting with just a 3/4 union (for connecting 2 pipes), or a cap? What is the thickest that you can cut with a tin snips? Maybe for your next buils show a step-by-step.


 
The first set of photos are from a 3/4" union and the second set are from a 1" union. I cut the thicker 1" stuff with tins snips - I'm not sure how much thicker than that you can go. I will try to remember to take step-by-step photos the next time I cut one up.

Supernam (you da Nam!), No pain, no gain! Nice to know someone is implementing and building on the idea.

Thanks Wayne and LED Zeppelin!

X_M, that's an interesting thought. I'm quite familiar with the effects of annealing on the mechanical properties of metals but I had no idea it also affects thermal conductivity. Or, more importantly, I had no idea that strain hardening reduced thermal conducitivity. It's probably not a very significant effect because these parts require very little cold working, but it would be fun to anneal one just for comparison. Thanks for the tip!


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## AlexGT (Feb 21, 2009)

Bump for an old and useful tread!

Thanks for posting the instructions!, I was able to make my own heatsink for a triflupic that I plan to use.

I made mine using a 3/4 copper plug, it has a flat surface ideal for mounting boards, I cut it using snips and dremel, decided to sand and polish the surface on a glass for a perfectly flat surface for mounting, whole process took me about 2 hours and $2 worth of copper plug.

Here are the pics, enjoy











Want to know how flat is that surface? Flat as a mirror!






Mounted on a Mag "C" light, There is enough space for the wires to pass thru on the side.











Thanks for watching!

AlexGT lovecpf


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## nein166 (Feb 22, 2009)

Nice pictures AlexGT I never seem to find the time to shoot pictures when I'm building a light. I love this technique and used it to mount a MaxFlex in a C Mag. Guess what no pictures.:mecry:


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## Aircraft800 (Feb 22, 2009)

Nice Tutorial and pictures! Good to see this thread again also.


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## SnowplowTortoise (Feb 23, 2009)

Cool! Seems a shame to cover that perdy thing up with a circuit board!


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