Melting Point of Plexiglass?

[upsmaster]

oopps www.aavidthermalloy.com

[Mike]

Thanks again to everybody.<p>I'm trying to cut out the hole for the power inlet connector. It's a standard one like in a PC power supply. I can't seem to find a template to cut the hole exactly to size. Does anybody have one?<p>[ November 27, 2004: Message edited by: Mike ]</p>

[kell]

for heatsinks try the surplus places like
www.allelectronics.com
www.goldmine-elec.com

[jwax]

For safety sake,use about a 50C (122 F) thermostatic switch. Most of the plastics mentioned will, with time, soften and perhaps discolor with prolonged temps above that.
Good idea mentioned also is to "insulate" the heat sink from the plastic- maybe use squares of double-sided foam tape, available from hardware, HomeDepot, etc. It's strong and will tolerate temperature, available in several thicknesses to give you an air gap.

[Mike]

Thanks<p>How about this heatsink?<p>http://www.goldmine-elec-products.com/p ... 4&mitem=15<p>Only a buck! if needed, I could get a few of them and hook them together.

[jwax]

Without the thermal math, I'd say that fellow will do nicely!

[Mike]

Thats what I was thinking. And you can't beat the price!<p>Do you think I need one per chip, or one for both?<p>Has anybody dealt with that company and could tell me the shipping rate for the cheapest method and if there is a minimum order?

[jwax]

Again, without the thermal math, one sink for both "should" be adequate. How often will you be running max power? If they do get hot, a thermostatically controlled fan could kick on, and you won't even be able to hear it!
Let us know how it works and looks!

[Edd]

I didn’t relate this post evolving into heat sinking until a later check back .
I might pass on, for all that this might be helpful to in the future, a sourcing of heat sinks that I started using about 35 years ago.
I had the occasion of a commercial business places aluminum frame door being damaged by a break with the necessity of it, as well as its massive door jamb also having to be replaced. That jamb turned out to be using ¼ in thick extruded aluminum in its construction.
Its minor cross members were utilizing 3/16 in thickness aluminum.
In the end I have 26 ft of 6 in x 4 in x1/4 in thick rectangular heavy aluminum channel stock shaped like [ .
And also about 16 ft of 4 in x 2 in x 3/16 in thick smaller rectangular stock.
That cache kept me in heat sink materiel for years, as well as using it for cases for small communications monitor receivers and instruments. I either made the cases to stock width or doubled the width, placing two pieces of the channel stock together.
Fabrication tools used, being a saber saw with a fine or medium metal cutting blade, really, with medium being the preferred, along with a square for lay out, and a final surface masking taping (to preclude the saws sole plate from scratching the aluminum) with a large flat mill file used for final draw filing and de burring.. The material has a hard anodized coating and I have seen dyes utilized for black, bronze (most common nowadays, really just a quite dark brownish/black), and gold colorization, as well as the common untreated, but anodized, natural aluminum color. Recently I came into some of the gold….very nice looking !
If heat sink fins were necessary to supplement the mass of a heat sink, they would be cut from the smaller stock and mounted with 2 countersunk/tapped flat head Phillips screws. That alum stock being truly flat. Fins were always being mounted vertically, to acquire optimal heat carry off from thermal convection rise.
Commercial glass installers have various sizes and configurations of this in their cut off/scrap bins as well as metal salvage yards. On my latest find I was offered about a 10 ft length of the gold stock that had not been deformed by bulldozing at a bldg teardown…merely for the asking.
I do have a metal brake but this has been my quick and preferred choice.
73's de Edd
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<p>[ March 17, 2005: Message edited by: Edd Whatley ]<p>[ March 17, 2005: Message edited by: Edd Whatley ]</p>

[fredje1]

Hey Mike:
If you go to All Electronics Website You will find just the heat sink that you want. The one that I have bought is about 3 and 1/2 inches by 3 inches and has a 1/4 inch thick base plate with 21 vertical fins that are 1 1/2 inches high here is the websight. http://www.allelectronics.com/ They use these for Processors but a little inginuity you can adapt for your project. Now don't go wild at this sight. You will se that they have everything from soup to nuts and real cheep. That heat sink that I am talking about is from their catalogue # HS-966 and sells for 2.5 dollars US. Hope this helps. chow

[fredje1]

Hey Mike:
If you go to All Electronics Website You will find just the heat sink that you want. The one that I have bought is about 3 and 1/2 inches by 3 inches and has a 1/4 inch thick base plate with 21 vertical fins that are 1 1/2 inches high here is the websight. http://www.allelectronics.com/ They use these for Processors but a little inginuity you can adapt for your project. Now don't go wild at this sight. You will se that they have everything from soup to nuts and real cheep. That heat sink that I am talking about is from their catalogue # HS-966 and sells for 2.5 dollars US. Hope this helps. chow

[Mike]

Thanks,<p>I ordered some of the ones from electronics goldmine, because I couldn't resist the price.<p>processor heatsinks haven't done too well for me. I built a 3886 amp using a P2 type heatsink, and the heatsink gets very warm when in use, even when not even cranked.<p>So, right now, I'll try the ones I'm waiting for now, and hopefully they will get here soon.<p>Has anybody ordered from electronics goldmine before? If so, how good was the shipping? They told me 10 business days, but I hope it will arrive sooner. I want to get this done by christmas so i can give it to my dad as a gift.

[Mike]

I have been taking some pictures as I build this, and thought I would post them here in case anybody is interested. I decided to use 2 heatsinks, one for each chip, because it was much easier to mount them to two heatsinks then to one (the holes already drilled into the heatsink fit perfectly). And, even with it cranked, the heatsinks barely even get warm.<p>Here are the pictures: http://www.electronet.dyndns.org/electr ... ctures.htm<p>Its obviously not done (the transformer and bridge rectifier need to be put on, the connectors need to be installed and the plexiglass needs to be cleaned), but its almost there.<p>I'll keep posting pics at that wrbsite as I get them.<p>Sorry for those who have dial-up connections, the pictures are about 120k each. I'll put together another page with lower resolution pictures if needed.

[Mike]

I've finished it!<p>Here are the pictures:
http://www.electronet.dyndns.org/electr ... tures2.htm<p>What do you guys think?

[Mike]

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