Aluminium foil wrapping

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Davx
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Aluminium foil wrapping

I see that many people use aluminium foil around the dropin to help heatsink. So i want to try to understand the best way to do it.

- What kind of aluminium you use, professional or "cooking" aluminium?

- You use also thermal compound?

Any photo or suggestion to do a perfect job are welcome.

"There are always new jobs, women, and apartments......there is only ONE BLF." - Chicago X (27/03/2012)

Vectrex
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Here you go - we need a tutorial category - http://budgetlightforum.com/node/1403#comment-21791

mitro
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I don't use any thermal coupound and instead of foil I use strips cut from aluminum cans. I cut them down until they are just long enough that you have to force the dropin to get it to seat properly.

Tas62
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http://www.hardwarefast.com.au/component/cubecart/?_a=viewProd&productId...

It's soft and maleable. Two turns around the drop in makes for a tight fit.

sixfink
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generic household aluminum foil for me. Even more malleable! Wrap tightly, and be patient.

press fit is good. the tighter, the better - if you magage to squeeze it in, it ain't too much.  My personal guideline: Holding a P60 with both hands and sloooowly pushing down on the wrapped drop-in. There shall be resistance which requires body weight, but not much more. No humping the light (gee, that sounds kinda perverted, eh?) The weight of your upper body (I weigh 210 lbs @ 6'3") should be enough to slowly drive it in. As I said, my own personal preference. The hosts and reflectos are incredibly stout, they won't collapse or break.

You want as little air between the layers as possible.

Fourteen semesters of architecture have taught me one thing: air is a pretty effective thermal barrier.

We neither need nor want thermal barriers when we are trying to dissipate heat.

Mr Frugal
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mitro wrote:

I don't use any thermal coupound and instead of foil I use strips cut from aluminum cans. I cut them down until they are just long enough that you have to force the dropin to get it to seat properly.

I like the can strips too.  They end up fitting so nicely that they stay put in the head of the tube when you remove the drop in.  Aluminium foil always ripped out with the drop in and had to redo it each time.  Also I was scared sometimes I was going to get a fragment of foil shortin something out.

photon1k
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Mr Frugal wrote:

mitro wrote:

I don't use any thermal coupound and instead of foil I use strips cut from aluminum cans. I cut them down until they are just long enough that you have to force the dropin to get it to seat properly.

I like the can strips too.  They end up fitting so nicely that they stay put in the head of the tube when you remove the drop in.  Aluminium foil always ripped out with the drop in and had to redo it each time.  Also I was scared sometimes I was going to get a fragment of foil shortin something out.

+1

I tried the aluminum foil and it works. But I found I had to re-wrap it each time the drop-in was removed. This becomes tedious if you're like me and like to swap it out or put it in another host. The aluminum can strips work much better for me.

kragmutt
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Could someone post pics of the aluminium can strips? Do you remove all the coatings? with sandpaper? What do you use to cut the can?

mitro
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I don't do anything to mine. It seems to work fine as-is.

Budgeteer
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mitro wrote:

I don't do anything to mine. It seems to work fine as-is.

Even with XM-L?

kragmutt wrote:

They're gonna send you a green redcat with a black LED.

Mr Frugal
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I used a coke can, just cut a can with a hacksaw enough to get at it with some heavy scissors, and then cut a strip as wide as the head of the tube. About an inch and a half less than the full length around the can made my drop in fit tight. The strip coils up real nicely in the head.  I tried to remove the coke printing but acetone would not remove it.  Bead blasting does but it distorts the strip way to much, so I just cleaned everything with brake cleaner and used just a little arctic silver between the head, strip and drop in.

jamesearljonesi...
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I found some muffin cups in the pantry. folded it up twice and rolled it around the p60 nice snug fit. does anyone use thermal paste on the threads where the pill screws in to the reflector or use it before they wrap? kinda messy but might help with heat transfer.

has anyone tested temps between copper tape/strips vs aluminum foil?

03/04/16 

 

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Don
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Problem with using thermal paste on threads is that most of it contains metal oxides - very hard metal oxides - or in other words, it is grinding paste.

 

I suspect that technique rather than material used will determine the temps.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

Budgeteer
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I use regular tin foil and try to eliminate any air pockets. Works fine for me. I always attempt to make a tight fit that i can still be able to pull the dropin out by bare hands if need be.

kragmutt wrote:

They're gonna send you a green redcat with a black LED.

jamesearljonesi...
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muffin cup 2.5"

flatten

fold 3 times

roll around dropin as tight as possible and push in while turning to seat.

03/04/16 

 

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brted
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For aluminum can strips, I use scissors to cut the bottom and top off of an aluminum can and then cut down the side to get a rectangle. Then I scrub both sides of the rectangle with a scouring pad to get the ink and/or plastic layers off of it. Then I can cut strips out of it. With a 12 oz. can I can cut out a long strip (full circumference of the can) that goes around the drop-in 3 times. I will cut shorter strips to fill in that might go around 1 or 2 times. The width of the strip varies. Some lights, like the 502B, require thinner strips (17mm), while others like the Solarforce L2 allow for wider strips (19mm). What I would really like to do is get some copper flashing for roof work and make strips out of that, but I haven't found copper flashing anywhere. It can be bought thicker than what aluminum cans are made from so there would be fewer layers and less air.

P60 drop-in with strips

Mr Frugal
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I'll have to try the scouring pad trick to remove the ink or whatever that logo is on the can.  I think too copper would be best.  Copper absorbs heat really well and aluminium dissipates better.  Thats why the good computer heatsinks are copper based to absorb the heat and aluminium fins to give it off.  

kragmutt
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Thanks for all the posts. I think I know what to do now.

Piers
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I still wonder why the p60 isn't just a btter fit in it's host. It just seems odd that you wouldn't make it almost a push fit to start with.

peteybaby
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Or screw-in.  that would be great, with some thermal compound in the threads.  I have a light whose pill screws in and its thermal transfer is really good.

I've been wondering if there might be some kind of putty-like thermal compound that we could use instead of strips of metal.  I found some.  I'm not sure whether to post links in this thread or start a new one...  I'll start a new one.

brted
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Pook wrote:

I still wonder why the p60 isn't just a btter fit in it's host. It just seems odd that you wouldn't make it almost a push fit to start with.

The story I've heard is that it was originally designed for incandescent drop-ins where you actually wanted the bulb to stay hot and you didn't want to transfer all that heat to the body where it would burn your hand.

kragmutt
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brted wrote:

Pook wrote:

I still wonder why the p60 isn't just a btter fit in it's host. It just seems odd that you wouldn't make it almost a push fit to start with.

The story I've heard is that it was originally designed for incandescent drop-ins where you actually wanted the bulb to stay hot and you didn't want to transfer all that heat to the body where it would burn your hand.

That actually makes a lot of sense. I think this is the same issue with replacing house lights with LEDs. The fittings are usually well insulated, since an incandescent could burn down your house.

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Has anyone else considered wrapping the drop in with a thermal pad, the kind commonly used on GPU heatsinks? They seem to be malleable and can compress when pushed into the housing. This would eliminate any air pockets between the pill and host. I found some on eBay for a couple of bucks, but I'm concerned that the thermal conductivity isn't good enough to make a difference (2w/mk).

 

Any input?