aluminum heatsink anodizing
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From: Phil Allison on 19 Dec 2008 17:47 "Eeysore" > Who said anything about blowing ACROSS a heatsink ? That's about the > dumbest > thing to do. ** Yeah right - blowing it straight through the metal and out the other side is WAAAAY more effective. Every fool knows that one. ...... Phil
From: Eeyore on 19 Dec 2008 17:49 Rich Grise wrote: > Eeyore wrote: > > Jamie Morken wrote: > > > >> Does an anodized or painted aluminum heatsink perform better thermally > >> than a bare aluminum heatsink for the situation of to-220 components > >> attached to the heatsink with sil-pads? > > > > No simple answer. > > Sure there is! > > The thermal resistance of sil-pads is so crappy, the treatment of the > heatsink itself won't make much difference. > > If the device makes _good_ thermal contact, then anodized/painted is > better. Plain aluminum has very poor emissivity. Only in pure convection cooled applications. And yes, I had them anodised black in that instance. Graham
From: Phil Allison on 19 Dec 2008 19:18 "John Devereux" > Phil Hobbs explained it pretty well I think. ** But only from his blinkered point of view. > But really it is properly descibed as convection in both cases, ** You are making that same dumb, pedantic error yet again. There is no " properly " about it - that is just declaring yourself to be RIGHT !! What is "proper" is purely a matter of what is common usage in some area of technology or commerce. Where it is important to make a distinction between products that either do or do not have internal fans - avoiding the word " convection " in the former case avoids an obvious confusion. ..... Phil
From: John Fields on 19 Dec 2008 19:32 On Fri, 19 Dec 2008 22:45:27 +0000, Eeyore <rabbitsfriendsandrelations(a)hotmail.com> wrote: > > >Phil Allison wrote: > >> "Adrian Tuddenham" >> > >> > A point not often appreciated is the possible heat gain when a heatsink >> > is operated in bright sunshine. A surface finish which is a poor >> > radiator/absorber of radiant heat will work better in those >> > circumstances. >> >> ** Only a complete dope would not find some way to shade the heatsink from >> direct sunlight on a hot day. > >There's no shortage of dopes. --- And you're the proof of the pudding. JF
From: Rich Grise on 19 Dec 2008 19:39
On Fri, 19 Dec 2008 22:15:43 +0000, Eeyore wrote: > Rich Grise wrote: >> Eeyore wrote: >> > John Larkin wrote: >> >> >> >> Hint: smart people machine the heat sink *before* they anodize it. >> > >> > Who said mine need any machining ? >> >> If it's extruded, it needs to be machined, especially if you're >> intending to use the hard anodize as the insulator. > > Who said anything about extrusions ? Every sizeable heatsink I've ever seen has been extruded. What are you doing, having them cast? Maybe machined from a solid block? Please, tell us more about these magic heatsinks that don't need any heat grease/paste with your magical pads, of which you seem to be the only happy user in existence. Thanks, Rich |