Help - heatsinks warped

[bpetrus]

Last year I purchased several heatsinks during the R-Theta group buy. I have finally gotten around to building the amplifier (a 100W AlephX). However, I have noticed a slight curvature of the heatsinks - concave when looking directly into the fins. The displacement at the ends of the heatsink is about 1/8-3/16 of an inch. The problem is that the heatsinks now do not align with the baseplate and case top. Is there any way to unwarp these heatsinks? The dimensions are 11 x 15".

Brad

[mwmkravchenko]

Place the sink on two boards so that the greater part of the sink is not being supported by anything. Get yourself a piece of wood that will fit into the slots and touch the top of the plate. Take a BIG ( I mean BBBIIIGGG ) hammer and gentle tap it untill it is flat. Make sure you check frequently that you have gone far enough but not to far. The idea with the big hammer even a sledge hammer is that the blows can be smartly directed and they will get the job done right. A small hammer will just not do it. If you don't have a hammer you can use your own weight to flex it back into shape by using the blocks as stated and a board with a blck placed in the middle to concentrate your weight in the correct spot. A bucket or something to support your weight onto the heat sink.

Think it over and give it a shot.

Mark

[bpetrus]

Hi Mark,
Thanks for the reply. I guess I need to go out and buy a big hammer!
Brad

[Sch3mat1c]

The proper term is BFH (Big F**narkling Hammer), and it *will* be loud.

Tim

[bzo]

I'll be curious to know if this works out for you. I have a similar problem with some heatsinks I have also. However, have been reluctant to try this approach as I worry that it may make the problem worse. If the base does not bend uniformly, it seems to me that more complex bends/warpage could be created.

I tried clamping my heatsink down to a piece of flat metal stock, but unfortunately, the bend seems to spring right back even after extended clamping.

http://diyaudio.com/forums/showthrea...567#post376567

[rwagter]

I know this problem, I had the same with my aleph5 heatsinks:


and this is what fischer says about it (DIN standards)

http://www.fischerelektronik.de/_200...l_PDF/A_11.pdf

+/-3.5mm tolorance on 440mm heatsink is not unusual

[bpetrus]

rwagter,

Yes, that picture illustrates the problem I have. Were you able to fix this problem?

Brad

[Sch3mat1c]

Could always take it and a six pack to a local machine shop and have them mill it flat.

[bpetrus]

Sch3mat1c,

That's a good idea but would result in loosing 1/8 - 3/16" in the horizontal center of the heatsink. The heatsink is only about 1/4" thick (not including fins) so this would be a significant loss of heatsink.

Brad

[Magura]

Give it a wack with a hammer before you take it to the machine shop, in order to machine a little as possible.

Magura