What thickness of plexiglass is best to use for a water block?

Ok, so about three months ago I bought a 168W peltier unit off of ebay. I wanted to fool around with the cold side, the only problem was that I did not have a large enough heatsink to disapate the heat. And thus the peltier would overheat after 20 seconds. So last week I decided to make a water block out of the heatsink, the design was very simple, encase the heasink in plexiglass and add two hose barbs. Now my problem is that I can't decide on the thickness of plexiglass I want to use, 1/16" would be nice but I worry that it will break, and 1/8" is a little more expensive. Any ideas?

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Thickness doesn't matter that much. Regarding stressing flexible seals, they're MEANT to be stressed, they're inteded to adapt to small shifts of motion and position. What's far more crucial is the material. Acrylic is best. Polycarbonate might be a tempting choice because it's known to be tougher but it slowly cracks under constant (even gentle) stress. Acrylic also has a better chemical resistance. 1/8" should be plenty for thickness on something as small as a CPU block. 1/4" would be overkill except when you're using liquid weld stuffs like Weldon, because acrylic is moderately brittle and the joins are never as solid as the substrate. If you're using clamps and flexible compression seals, 1/8" is enough.
frollard8 years ago
1/16 is pretty flimsy. They tend to use BIG stuff on waterblocks - like 1/4-1/2 inch so it doesnt bow under any sort of pressure. Any flexibility will result in stressing the silicone/rubber seals. Go with the thicker, hands down. It's not THAT much more expensive, and you'll have a more rugged product.
junits15 (author)  frollard8 years ago
wow it's like you read my mind! that is exactly waht I was thinking O_o
lemonie8 years ago
Sounds dangerous (water everywhere is what I see). Could you use copper-tubing and solder instead? L
junits15 (author)  lemonie8 years ago
Oh this isn't going in my computer this is just to fool around and maybe make a mini fridge, besides I have a laptop :D
There is a USB (Peltier-based) mini fridge Instructable somewhere - search this site. L
junits15 (author)  lemonie8 years ago
yes I've already seen that, I'm just wondering if I should use 1/16" plexi or 1/8"
I think you'd be better with the 1/8" - easier to work with, less flimsy?