My LHBS gives away free cigar boxes. They look nice and you can find them for a couple of bucks on ebay. A hole saw would work very well on them as well.
I had a similar issue with the ps not spinning the fan fast enough with my first assembly. I did end up using a more powerful ps and it now spins the bar just fine. I also had issues with my bar being thrown. I ended up using a washer that I have centered and on it is the magnet as centered as possible. The bar hasn't been thrown once ever since. My guess is you need a higher amperage ps and the mag needs to be centered more.
Found a 12v 900mA PS late last night. I hooked that up this morning and there is definitely more power now. I can get a nice 2L vortex, but it only reaches about halfway down the flask, is this a problem?
My last problem is really just flask design. I have Pyrex flasks and they have a little bulge at the bottom of the flask. This causes the stir bar to be awfully noisey. Anyone else have this happen, and find a solution, or should I just learn to ignore the noise.
Thanks.
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Another problem I'm having is adding the washer. I'm having a real hard time centering it. I've been testing it all out with duct tape first, before I glue anything down, and no matter how much I think I've centered it and the magnet, I get wobbles when I switch the fan on. I'm actually having better luck with just the magnet, and no washer, only problem is the short vortex as stated above.
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built mine tonight....easy to do with these instructions. off to buy a bar and flask tomorrow
I thought that I would post what I bought today to build my stir plate.
I bought this fan (Comes With Fan Controler!!!)
http://www.newegg.com/Product/Product.aspx?Item=N82E16835200020
$7.99 - $1.59 (Discount Code BTEKAJA22) + Free Shipping = $6.40
mredge73 said:Works just fine with a 1" stirbar. Does not work with my 1.5" stirbar, fan not strong enough. There are much better fans out there but I couldn't pass on this deal.
What drill bit size is necessary for the switch holes?
I have mix and match drill bits at home, but I gotta stop by ace to get my few remaining parts and wanna pick up the correct size drill bit so I can get this completed tonight.
I was asked to build a couple of more of these but I am out of magnets. What size do you guys order?
twd000 said:I got a brand-new 12 Volt DC brushless fan from Radio Shack.
12VDC Brushless Fan : Computer Fans | RadioShack.com
I had it working for a few minutes, off a 12 VDC/500mA wall wart. Later in the course of hooking up the rest of my control circuit, I noticed that the fan no longer spins when voltage is applied. It "locks up" the rotor and won't free spin until you remove voltage. Is it possible to fry one of these things by applying voltage in reverse or something?
I have tried powering it directly with the 12 V supply, and a 4.5 V supply, and it just locks up and won't spin until I remove voltage.
I've never seen a fan get damaged by reversing the wires... I do it all the time.
Is it possible that you have the wires reversed right now? Or maybe there's a short?
Flomaster said:In don't know the answer, but I went through 4 fans and several power supplies before I found a working combo.
twd000 said:Well I don;t have the wires soldered - I'm just twisting them together. So I have tried both ways. One way nothing happens, the other way the fan "jumps" then locks up. There no way for a short in the external wiring - just a single red and black wire, and they're not touching each other. I'm wondering if there is a transistor or diode internally that I fried, that could cause a short?
Ah. It actually sounds like the adapters have simply been underpowered, then. In terms of amps, that is.
twd000 said:The plug says 500 mA @ 12 VDC, and the fan lists a max of 0.32 A (320 mA) so it should be more than enough, no?
Depends... the startup requirement may be higher, but you usually have to find that from the manufacturer's site.
Ah, right.
Do you happen to know the make and model of the fan?
And did you buy it new, or pull it out of a PC?
If you have your neo mags on it that can hose you. Try without the mags. If it works remount with more shielding (aka more washers, they can be sandwich glued together).
WTF?
Do you even look at the power ratings of the fans and the powerful supplies? If you provide a decent voltage, and the adapter is able to meet the fan's minimum amperage requirements (both operating AND startup), there's no reason it shouldn't work, unless you have defective components.
Assuming they're not defective, there really shouldn't be any guessing or trial-and-error involved in finding two components that work together. None whatsoever.
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