Great American chamber bake-out

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AnGuy
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Re: Great American chamber bake-out

Post by AnGuy »

>Some of that contamination will coat the interior of your Turbo and despite the flogging the impellers give to everything, their is still some boundary effects that partially screen the surfaces of the rotors and stators.

I hadn't thought about that. That's sounds like a good point

>For High Vacuum, high voltage assembly, we have always used the latex powder free gloves, to minimize contamination.

All the brands of "powder free" latex seem to have some powder. The best I came across are "Nitrile" gloves which don't have any powder. I was hoping you might know of a vendor that sells latex for clean rooms.

What about latex and acetone? I was concerned that acetone might react with the acetone. From what I read, Acetone and Methanol are the two best for degreasing vacuum devices since they leave no residue. However, I really don't like the idea of using Methanol for cleaning since its very toxic and can seep past skin into the bloodstream.

Thanks
Todd Massure
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Re: Great American chamber bake-out

Post by Todd Massure »

I seem to remember that the cheapo vinyl gloves like food handlers use didn't seem to have any powder
AnGuy
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Re: Great American chamber bake-out

Post by AnGuy »

>Could I expect to get less outgassing from the ceramic parts in a fusor than the metal per given area? Does the feedthrough require any different preparation and handling than the metal?

To my knowledge, as long as your not using a metal containing lead, cadium or zinc (galvanized, brass) you should be fine. The problem is that all metals can retain water and hydrogen on the surface. When you pump down these substances (and any containments) will outgas.

One issue you may run into with ceramics is with porous materals that can hold water, air or other containments that will outgas. You should not have a problem with the cermics from manfactured feedthru. However if you plan to place cermics inside, be sure to used alumina or glasses that are not porous. I believe some of the glazes used on ceramic can also be a source of outgassing.
DaveC
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Re: Great American chamber bake-out

Post by DaveC »

Sorry about forgetting the glove source. One type is medical latex gloves which are powder free. Brand is Evolution, but not sure of supplier. Almost certain McMaster -Carr carries them, would think other suppliers like Cole-Parmer, VWR, and Wal-Mart carries them.. (but not sure if they are powder-free).

Acetone and methanol will attack them in time. I always use them if I have to clean things extensively with these solvents.
Using these solvents without the gloves, often makes it very difficult if not impossible to avoid depositing finger grease which the solvents extract from your skin.

Hope that's some help.

Dave Cooper
Jon Rosenstiel
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Re: Great American chamber bake-out

Post by Jon Rosenstiel »

Anonymous Guy wrote:
> I use gloves because I usually ended up with a half a dozen tiny, razor sharp stainless splinters when machining with stainless. The gloves definately help. The splinters are often extremely difficult to remove or even see if your hands are dirty.

Please be careful. Wearing gloves around machinery is not a good idea. Much better to have a few cuts or splinters than to have your extremities pulled into a machine.

Jon Rosenstiel
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Richard Hull
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Re: Great American chamber bake-out

Post by Richard Hull »

Jon is right, I have had a couple of close calls over the years and one horrible accident where a lathedog hit my hand and knocked it not into the machine, but back around behind me. Hurt like a son- of-a-bitch and bled like a stuck pig.

Rolledup long sleeve shirts are a no-no as they will unroll at a critical moment and pull an arm into the works. The classic light weight leather lathe apron is a real nice thing to have. Bare hands and a lexan face shield are best. Bare hands are best protected by filing or deburring rough or sharp machined edges prior to removal of chucked work. Goggles are fine, too, but the face shield will help deflect a small missle or two that goggles will not.

Still, you will get scrapes and cuts no matter what. The number, severity and frequency are directly proportional to your total machining time over the years and your attention to deburring sharp fragments prior to handling.

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
AnGuy
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Re: Great American chamber bake-out

Post by AnGuy »

>Please be careful. Wearing gloves around machinery is not a good idea. Much better to have a few cuts or splinters than to have your extremities pulled into a machine.

Nothing to worry about. I am wearing latex gloves, similar to surgical latex gloves. If the glove got caught in the machinary, it would break. They are very thin and break pretty easy and are designed to use with machinery. I would never consider wearing cotton or work gloves.
AnGuy
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Re: Great American chamber bake-out

Post by AnGuy »

>Using these solvents without the gloves, often makes it very difficult if not impossible to avoid depositing finger grease which the solvents extract from your skin.

What I was concerned is that the solvent would break down the latex and leave a latex reside on metal surface and present another source of outgassing. But, if you haven't had any trouble, I will consider using them.

>One type is medical latex gloves which are powder free. Brand is Evolution, but not sure of supplier

Thanks, I didn't think about using surgical grade gloves, but that makes sense. Any containments on gloves would likely end up in the patient, so that must be very clean.
AnGuy
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Re: Great American chamber bake-out

Post by AnGuy »

>Bare hands are best protected by filing or deburring rough or sharp machined edges prior to removal of chucked work

The problem isn't the machined edges is the taillings left from the machining mixed in with the lubercant. They end up every where. Its impossible to clean them up with out getting some on your hands, and they are very tiny and razor sharp. It doesn't take much pressure to get a few lodged under your skin.


>have had a couple of close calls over the years and one horrible accident where a lathedog hit my hand and knocked it not into the machine, but back around behind me. Hurt like a son- of-a-bitch and bled like a stuck pig.

I haven't done any work on a lathe yet, just a vertical mill. For my turned parts I use a radial table or a rotary indexer with a lathe chuck. I would like to get a lathe, but it would be real a pain to get it moved into the basement.

When I operate the machine I am very careful to keep all body parts and clothing away from spinning tools. So far I've not had any accidents, except perhaps hitting the back of my hand on a stationary tool bit while tighting down a clamp with a wrench. Carbide bits are extremely sharp!

Another import issue to to avoid touching your head where swarf (tailings) can get into your eyes, even if you wear googles or a face shield. I am always concerned that tiny piece will end up in an eye or even on a lip where it can be ingested. Another issue is tracking swarf upstairs since tiny sharp pieces can get stuck on the bottom of your shoes or even your clothing, and end up on the floor. Stainless is awsome metal, but machining it absolutely sucks. I much perfer to machine aluminum or even steel.
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Richard Hull
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Re: Great American chamber bake-out

Post by Richard Hull »

Machining stock 304 stainless is actually easier than machining mild steel. The key is to use the absolute correct computed tool speed. It cuts similar to brass and carbide tools are not needed, though they help a bit by staying sharp longer. As usual most of the bad rep on stainless comes from folks burning or chattering tools to death without taking the time to compute and adjust the machine speed to precisely the recommended turning surface speed. Once done, I have done light SS machining DRY! It has to be seen to be believed by all who have smoked or chipped carbide tools on SS machining.

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
AnGuy
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Re: Great American chamber bake-out

Post by AnGuy »

>Machining stock 304 stainless is actually easier than machining mild steel. The key is to use the absolute correct computed tool speed. It cuts similar to brass and carbide tools are not needed, though they help a bit by staying sharp longer.

Cutting Stainless isn't the problem, Its the super sharp and tiny chips that I hate.
3l
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Re: Great American chamber bake-out

Post by 3l »

Hi AG:

Fusion wants your BLOOD!

Happy Halloween!
Larry Leins
Fusor Tech
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