Straightening heatpipes

StealthGirl · Post by **StealthGirl** » Thu Sep 30, 2004 11:11 pm

Does anyone have any ideas on the best way to un-bend heatpipes? In frustration of not being able to get samples (or for that matter any cooperation from any manufacturers), I bought a Zalman HC-1 hard drive cooler to use the ten pipes. As you know, these are bent 90 degrees on the ends. However, in a quick hot water test, I found out there is very little heat transfer past these bends (the straight portion works great though). So, since these heatpipes are known to be grooved cores (as little websurfing turned up) there isn't a powdered core inside to breakup by straightening them out. However, these copper tubes ARE very thin, and I don't want to flatten them out in the process. So, any ideas?

Thanks in advance,
Kate

silvervarg · Post by **silvervarg** » Fri Oct 01, 2004 5:06 am

I suggest that you have some kind of mold that is hard and can withstand heat that has the shape you want. Mold should be split in two pieces.
Fasten each side of the mold to a vice.
Heat up the part of the heatpipe to straiten to 100-200 C.
Put the pipe in the mold and start to close the vice slowly.

It could possibly work without heating the pipe, and that would make things much easier since you could then make the mold by just drilling a hole in a piece of wood and then cut the wood in half.
Since you have quite a lot of pipes to experiment with I would suggest that you try without heating the pipe.

I have not tried this procedure on heatpipes, but it works for straitening/bending/shaping lots of other metal things.
Please keep us posted on how it works in reallity.

wim · Post by **wim** » Fri Oct 01, 2004 8:46 am

kate,
how did you pull the heat pipes out of the zalman hd cooler thing? i wanted to do some experimenting with them too but they seemed kind of mashed in there and pinched by the metal

efcoins · Post by **efcoins** » Fri Oct 01, 2004 8:58 am

You need

http://www.plumbworld.co.uk/acb-1526
cost all of $1

Heatpipes rupture at about 150C, less if they have bends in them, DO NOT HEAT THEM

Post by **Ralf Hutter** » Fri Oct 01, 2004 1:30 pm

efcoins wrote:You need

http://www.plumbworld.co.uk/acb-1526
cost all of $1

Heatpipes rupture at about 150C, less if they have bends in them, DO NOT HEAT THEM

Those do work great for bending copper tubing but you need to have access to the end of the tube to slip the spring over it. Can you remove the heatpipes from the aluminum (or whatever it is) heatsink? If not, how would you use that thing?

StealthGirl · Post by **StealthGirl** » Fri Oct 01, 2004 4:18 pm

Wim and Ralf,

I bought the older Zalman model HC-1, (not the HC-2), exactly because the aluminum side plates are screwed in. Here is a picture:

http://pg.photos.yahoo.com/ph/stealthgi ... m=6249.jpg

The pipe bending tool won't work because these pipes are only 5mm in diameter. I think I'll try building a wood form like Silvervarg suggested, but without the heating idea because they are way too thin to withstand that.

Thanks guys.

StealthGirl · Post by **StealthGirl** » Fri Oct 01, 2004 5:56 pm

Opps ... pic is available now

Raster · Post by **Raster** » Fri Oct 01, 2004 10:11 pm

I did the same thing(HC-1). I had trouble getting the screws off, so I had to drill some of them out. But you get 10 pipes. This was the only way I could find to get inexpensive pipes. The drawback is the shape. I got nowhere contacting companies: no response, no can do, or just some samples. Pretty frustrating.

StealthGirl · Post by **StealthGirl** » Fri Oct 01, 2004 10:36 pm

Raster,

My turn to say "WELCOME TO SPCR!"

So, do tell us, have you used your heatpipes yet? Did you straighten them?

Inquiring minds want to know

Raster · Post by **Raster** » Sat Oct 02, 2004 8:36 pm

I haven't done anything yet. I read here that the Zalman pipes are not very good. I haven't tested the thermal properties against a 5mm copper rod, but that would tell a lot about them. I was interested in heat pipes in high school (a long time ago) and got interested again after reading Fred Mahs article, but got nowhere on finding a source until I saw the HC-1. My interest was to eliminate all the fan noise by making a custom aluminum T-type open air case like Fred's but from square and flat stock instead of a plate, changing out the power supply for the Antec Phantom 350, and building a 7 pipe CPU heatsink from the Zalman pipes, copper stock, Arctic Silver thermal epoxy, and some parts from a real heatsink. Don't know if this will work yet. I have half of the frame constructed.

Thanks for the welcome. I have been reading SPR for quite a while.