DIY COB LED Heatsink - Heat pipe from recycled baseboard

Hadez411

Well-Known Member
So I've been reading up on heat pipes, which seem fairly simple to make and are well explained in this video.


I noticed that baseboard heaters have a 3/4" copper tube with aluminum fins already on it and people are regularly throwing them out. You just need to buy some copper fittings, try your hand at soldering or ask a friend, and with barely any money you'll have a water vapor heat pipe cooler like they're all shifting over to in the CPU market. A low tech one, but I'm sure you could make up for that with the size of it, given that your materials are fairly cheap and the heat pipe distributes heat very quickly and evenly. Even for a new 8 ft baseboard heater at Home Depot it's only about 10$/FT and I doubt you'd need more than a foot per COB. That comes in at a lot less than the 30$-110$ heat sinks for the 60W and up cobs.

Below is a photo of an electric baseboard element. From my past experience messing with them, the fins aren't welded or bonded and once you start pulling them apart they tend to fall apart and it can become a mess. So I intend to solder them to the copper pipe wherever I can to increase their thermal transfer efficiency and keep them from going all over the place. However it might be handy when soldering the other parts to completely remove the fins as they will be counter productive to your soldering efforts.



Below is an example of a heat pipe heat sink for cobs, 150$ on digikey.ca. Computer ones look sort of similar, bunch of skinny copper pipes that feed up and are covered in thin heatsink fins with and without a fan.




What I'm imagining would be similar, enjoy my MS Paint skills.
Heat Pipe Heatsink.jpg


Apparently the heat pipes work best at a slight angle (for the condenstate to return) so maybe you'd have to put in a 45 degree elbow if you have your lights pointed directly downwards. Same goes for if you're side lighting and your lights are sideways, the steam and condensate don't transfer heat as well without a wick.

I feel like these coolers would work best if you have a steady low level breeze in your grow area that can gently circulate air through them. However, putting up to 1 foot of aluminum fins on a heat pipe should make for some very significant cooling. Fanning could become unnecessary if you can include a 45 degree elbow, angling the tube to convect air up between the fins and improve the condensate return. I'm going to have to do a bunch of testing this week and find out. I'm using a vero 29 D at 60W
 
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Airwalker16

Well-Known Member
So I've been reading up on heat pipes, which seem fairly simple to make and are well explained in this video.


I noticed that baseboard heaters have a 3/4" copper tube with aluminum fins already on it and people are regularly throwing them out. You just need to buy some copper fittings, try your hand at soldering or ask a friend, and with barely any money you'll have a water vapor heat pipe cooler like they're all shifting over to in the CPU market. A low tech one, but I'm sure you could make up for that with the size of it, given that your materials are fairly cheap and the heat pipe distributes heat very quickly and evenly. Even for a new 8 ft baseboard heater at Home Depot it's only about 10$/FT and I doubt you'd need more than a foot per COB. That comes in at a lot less than the 30$-110$ heat sinks for the 60W and up cobs.

Below is a photo of an electric baseboard element. From my past experience messing with them, the fins aren't welded or bonded and once you start pulling them apart they tend to fall apart and it can become a mess. So I intend to solder them to the copper pipe wherever I can to increase their thermal transfer efficiency and keep them from going all over the place. However it might be handy when soldering the other parts to completely remove the fins as they will be counter productive to your soldering efforts.



Below is an example of a heat pipe heat sink for cobs, 150$ on digikey.ca. Computer ones look sort of similar, bunch of skinny copper pipes that feed up and are covered in thin heatsink fins with and without a fan.




What I'm imagining would be similar, enjoy my MS Paint skills.
View attachment 4306246


Apparently the heat pipes work best at a slight angle (for the condenstate to return) so maybe you'd have to put in a 45 degree elbow if you have your lights pointed directly downwards. Same goes for if you're side lighting and your lights are sideways, the steam and condensate don't transfer heat as well without a wick.

I feel like these coolers would work best if you have a steady low level breeze in your grow area that can gently circulate air through them. However, putting up to 1 foot of aluminum fins on a heat pipe should make for some very significant cooling. Fanning could become unnecessary if you can include a 45 degree elbow, angling the tube to convect air up between the fins and improve the condensate return. I'm going to have to do a bunch of testing this week and find out. I'm using a vero 29 D at 60W
Interesting. I think the main thing is height restrictions. But this could work. Get to it and show us what happens already!!
 

delstele

Well-Known Member
Subbed!! Another option for the finn's; a sheet copper soldered to the pipe this would allow some flexibility with thickness and shape.. @ $10 a foot for the base apparatus I'll bet with some creative thinking one could make a superior design with copper pipe and sheeting..
 
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Hadez411

Well-Known Member
Subbed!! Another option for the finn's; a sheet copper soldered to the pipe this would allow some flexibility with thickness and shape.. @ $10 a foot for the base apparatus I'll bet with some creative thinking one could make a superior design with copper pipe and sheeting..
I think you're right. I'm going to try making fins out of aluminum flat stock that I have and see how long it takes me.
 

Airwalker16

Well-Known Member
I think you're right. I'm going to try making fins out of aluminum flat stock that I have and see how long it takes me.
So some super thin sheet copper/aluminum used in what way? Square pieces with a hole in the center just like they are on the baseboard style?
 

Hadez411

Well-Known Member
So some super thin sheet copper/aluminum used in what way? Square pieces with a hole in the center just like they are on the baseboard style?
Ya, maybe larger fins though. Perhaps with holes in them to promote vertical through flow.

Im looking at cpu heatsinks and wondering why they want to use multiple thin pipes instead of one large.
 

Hadez411

Well-Known Member
Saw a cool DIY water cooler using the bottom of a pop can as a dome to glue or solder on to a plate. Gives you a small water pocket over your chip. His is for water in and out. Mine will just be a manifold of sorts.

His
cap0053.jpg
MineDSC_0475.JPG
 

Hadez411

Well-Known Member
I was thinking a condenser coil like whats used on AC units would be a option to look into.
I do have old diesel heater line, similar size and all. But I don't think it will work well with a twisty configuration if it doesn't have a wick inside. Also, thinner pipe means more pipes and more joints, soldering etc.
 
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Hadez411

Well-Known Member
I was thinking a condenser coil like whats used on AC units would be a option to look into.
You gave me an idea.

I could use the diesel line as both the copper tube and fin. I just need to fit a ton of them on to the pop can until it's a small porcupine of sealed 1/4" copper tubes.

15535594672802405751882220263601.jpg
 

TEKNIK

Well-Known Member
If you are going to spend the time playing about with heatsinks I suggest a water-cooled system
 

Hadez411

Well-Known Member
If you are going to spend the time playing about with heatsinks I suggest a water-cooled system
Passive is more redundant. If my water pump happens to fail, my lights likely die.

I'm tempted to try water and natural convection with a tank, but I have no idea if the flow would be sufficient
 

TEKNIK

Well-Known Member
You could set up a thermo shut down so if the cob exceeds a certain temperature it shuts things off, doing water cooling is complex but it does have great benefits. It is far too expensive to do this as a commercial off the shelf product but for DIY if you have the time it can work really well
 

Hadez411

Well-Known Member
You could set up a thermo shut down so if the cob exceeds a certain temperature it shuts things off, doing water cooling is complex but it does have great benefits. It is far too expensive to do this as a commercial off the shelf product but for DIY if you have the time it can work really well
Ya, it looks a lot more effective, cheap and lower wattage. I'm looking at a 140 gpm fountain pump with 1/2" hose, "3 ft push height" (1.5 psi?) for 15$ and cheap amazon water manifolds. I'm having a hard time coming up with a cheap radiator though.

This is for 8 cobs, 60w each

Do you know of a cheap diy radiator that is grow room size appropriate? I guess I could put a long hose on it and leave it outside for better results too.
 
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TEKNIK

Well-Known Member
I would be using a car electric water pump and a car radiator. Flow rates and pressure is what you need to find out when doing something like this.
 

Hadez411

Well-Known Member
I would be using a car electric water pump and a car radiator. Flow rates and pressure is what you need to find out when doing something like this.
I was reading that you want slow flow and high temperature differential
 

TEKNIK

Well-Known Member
It depends on how you set it up, if there is a long distance to run you will need higher flows. I would have the radiator out of the room so this would increase the distance the water had to travel and also higher pressure would be needed
 
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