Galvanized Steel?
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Logan Noel
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Galvanized Steel?
From everything that I've heard it is preferable to use stainless steel in fusor construction, but galvanized is simply quite easier to obtain. I'm wondering if anyone knows whether there would be any issues if I used galvanized instead of stainless?
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Chris Bradley
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Re: Galvanized Steel?
The issue is zinc's vapour pressure.
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JohnCuthbert
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Re: Galvanized Steel?
Really?
From that graph, if the stuff is at 200C it has a vapour pressure of something like 10^-6 torr and fusors typically have something like 10^-2 torr of D2 so you would have 0.01% Zn- which isn't great but if you keep the temperature below 100C the pressure drops below 10^-9 torr and I doubt that's a big problem . (You will have more than that much air leftover in many cases).
On the other hand, the Zn coating will oxidise and, in moist air it will trap water vapour so it will be a virtual leak.
I can't help thinking that the rough reactive surface of the zinc plating would be more of an issue than the vapour pressure per se.
From that graph, if the stuff is at 200C it has a vapour pressure of something like 10^-6 torr and fusors typically have something like 10^-2 torr of D2 so you would have 0.01% Zn- which isn't great but if you keep the temperature below 100C the pressure drops below 10^-9 torr and I doubt that's a big problem . (You will have more than that much air leftover in many cases).
On the other hand, the Zn coating will oxidise and, in moist air it will trap water vapour so it will be a virtual leak.
I can't help thinking that the rough reactive surface of the zinc plating would be more of an issue than the vapour pressure per se.
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Andrew Seltzman
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Re: Galvanized Steel?
Stainless hemispheres are easy to obtain and cheap:
http://www.sharpeproducts.com/store/hem ... genumber=2
http://www.sharpeproducts.com/store/hem ... genumber=2
Andrew Seltzman
www.rtftechnologies.org
www.rtftechnologies.org
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Richard Hull
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Re: Galvanized Steel?
Idea.................Spend your money and your time and your effort to build a galvanized chamber. Experiment with your money and your time to prove this a wrong negative on our part.
The overall temperature of the device is meaningless in this discussion as there are a myriad of localized hot spots where ion and electron beams impact the shell. The overall shell temperature is a time ordered summation of these rather localized, intensely hot spots, minus what thermal convective transfer does to cool the large surface area of the shell.
There is a reason no scientific galvanized vacuum chambers exist where a plasma is present under a critically maintained vacuum.
Richard Hull
The overall temperature of the device is meaningless in this discussion as there are a myriad of localized hot spots where ion and electron beams impact the shell. The overall shell temperature is a time ordered summation of these rather localized, intensely hot spots, minus what thermal convective transfer does to cool the large surface area of the shell.
There is a reason no scientific galvanized vacuum chambers exist where a plasma is present under a critically maintained vacuum.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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JohnCuthbert
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Re: Galvanized Steel?
It's an interesting idea, but wouldn't answer the question. There's no doubt that galvanised steel would be a poor choice.
The point I raised was that it's not clear if it's poor because zinc is volatile (and, at low temperatures, it's not) or if the issue is the fact that, on exposure to air, the zinc forms a mixed carbonate/ hydroxide layer that would outgas like crazy.
The point I raised was that it's not clear if it's poor because zinc is volatile (and, at low temperatures, it's not) or if the issue is the fact that, on exposure to air, the zinc forms a mixed carbonate/ hydroxide layer that would outgas like crazy.