Discussion in 'Project Logs' started by riekmaharg2, 8 Jul 2010.
Thanks RonanH , whats the cross section W?
I would say it is the uncompressed size of the O ring though I could be wrong.
Or you could be right
The routing looks verry nice for a handdone job! niice !
Keep on going
Now I hate to put this comment in now, after the work as been finished already, but in the end it might make a difference.
Firstly... the heatsink looks awesome! Nice work on the milling mate, major cudos for the job well done.
Secondly, you might want to go back over those passes with a Ball end mill. Having sharp corners like that (from the end mill) is going to cause enlarged boundary layers in your loop and also lead to a larger pressure drop. I don't think it will be to substantial considering the length of your loop but if you don't get the results your looking for you could consider that as an alternative. Also, considering the size of the plate I can almost guarantee you will need to fasten the heatsink to the plexi in more than just the corners. My graduate project was to design, assemble, and test a natural convection chamber, and we used two custom milled 1/2in aluminum plates bolted at the corners with a gasket in the middle. We ended up having problems with leaking loops and had to incorporate another fastener in the middle of the plate to distribute the load on the gasket more evenly.
Now considering you are using aluminum to plexi, you probably will not be able to fasten them together as tight as we did (aluminum to aluminum) because you will almost certainly cause stress fractures in the plexi, so thats just something to keep in mind.
Hopefully I didn't miss anything if this has already been talked about, and hopefully none of this is insulting to your intelligence, I just tend to find that some of the simplest things are often overlooked even by skilled individuals such as yourself! I love watching your projects though man, keep up the good work and keep the entertainment rollin!
Yeah thats the only thing I could think of it being, Thanks.
Thanks sixfootsideburns , Yeah I'm gonna have screws all over around the edge and further into the center, with little O rings around each screw. In order to see what the flow is like, I'm gonna pump some water into the heatsink, then add some food colouring so I can watch how the water travels and then unscrew it to make the nessesary adjustments. Should be cool to watch too
The next update will be on the case top panels as I'm waiting for parts to finish the heatsink.
my guess is food coloring might be to light to really show the full effect. You can buy special dyes specifically to show you the flow of fluids though if your interested. I certainly would try food coloring first though, definitely the easiest way to go
Love your progress man, push forward and lets get this beast finished!
Yep will do if food colouring doesnt work. You can get pretty bright reds and greens in food colouring though.
I guess my concern wasn't so much brightness as it is density of the color. Though this is really just me being a nay-say... I thought about this on my way to work and I should really stop posting suggestions like that until I know if your idea has worked or not!
Again man, excellent work so far. Its great to see people like yourself take such initiative and try new things. Chances are the food coloring will work perfectly anyways!
Lol, its ok I always welcome suggestions and ideas
Hi everyone heres the next update:
I started by milling out the channel for the O ring:
I then drill, taped, and sanded the heatsink:
I also drilled holes through the acrylic sheet:
Heres the screws I'm gonna use:
The reason their not countersunk ones will be revealed later. There will also be little o rings around each of the inner screws.
This update would have been bigger but I'm waiting for a load of parts which should have arrived on friday and they still havent.
Wow... the heatsink is awesome!
Awsome work on that heatsink especially since you made it on a manual mill.
I would guess that you might need more than 3 screws on the edges though, but there's only one way to find out
Keep it up.
Your heatsink is amazing man, keep going!!
Looking good, but I'd agree with The_Gnu, I think you'll need more screws, at least 4 more per side I'd guesstimate, maybe 6. Really depends on how thick the plexi is and that sheet looks pretty thin/flexible so may not pull down evenly.
Not hard to add more though
Are you not concerned that you'll get flow across the channels (the gap left by the small o-ring under the middle screws)? You might need to put a seal all the way around the spiral to prevent this... lot of machining though, might work without doing that... hopefully
EDIT: Just noticed the length of screws you're using... you have a plan to put a piece around the edge of the plexi by any chance? Hence not needing more holes? Keeping us in the dark, me likes it
The work with heatsink and the other pieces os the case are awesome!
Thanks everyone , you guessed right RonanH there will be a metal panel on top of the acrylic which the screws go through before going through the heatsink.
The O ring seal arrived today heres a pic of the acrylic temporarily screwed on:
The nuts under the screw are to fill the gap where the metal panel will be when its finished.
I then drilled the holes out for the barbs:
Unfortunately I got this far then I relised I had been sent the wrong Tap! So I'll have to wait again for a new one . Royal mail also seems to have lost the LED's I ordered over a week ago which are needed to complete the top panel .
The 5mm acrylic seems to be coping fine with the lack of screws even without the metal panel on top.
Wowzers, looking goooood .
Oh that's puuuurrrty with the acrylic on top
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