Vacuum Chamber Construction

For posts specifically relating to fusor design, construction, and operation.
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Richard Hull
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Re: Vacuum Chamber Construction

Post by Richard Hull » Wed Jan 15, 2020 4:40 am

Keep practicing, you will get there. Getting the current set right and your speed during the weld is critical. The puddling, if done well, will sort of set the speed of movement automatically as you get familiar with it.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

John Futter
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Re: Vacuum Chamber Construction

Post by John Futter » Wed Jan 15, 2020 6:06 am

Nic
You need some scraps of stainless about the same thickness as you are going to weld in anger
stainless is very much different from steel to weld --infact I find stainless much easier --but I was taught how to weld on Stainless

good Luck

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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause » Tue Jan 21, 2020 3:16 pm

Thanks for the tip John, I found a metal supermarket up here in Edmonton and picked up some 304 SS offcuts of about the same thickness as my chamber. Last night I was able to get setup and make some passes, the photo below shows some of my handiwork. I started on the right just passing the electrode and controlling the puddle, then I added in the filler rod. Wasn't great to start but the welds started to improve. At that point I'd mucked up my electrode and had to regrind which accounts for the mess after a few decent lines. When I went to restart the welding mask I was using started to go on the fritz, it wasn't auto-darkening properly. I'd read some decent reviews online that I thought justified me saving a bit of money on some safety gear from China. Rather than try and fix it I think I'm just going to write off the cost since I bought the cheapest I could find and spend a bit of money on a half decent one.
IMG_0918[1].JPG

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Rich Feldman
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Re: Vacuum Chamber Construction

Post by Rich Feldman » Tue Jan 21, 2020 7:09 pm

I can attest that sunburn is a risk if you skip the gloves and long-sleeve shirt, buttoned up at least as far as the bottom of welder's mask.

Even TIG welding can occasionally pop & launch a shower of sparks,
actually incandescent droplets of steel which you don't want to fall into your shoe or pocket.
All models are wrong; some models are useful. -- George Box

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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause » Thu Jan 30, 2020 5:02 pm

I've continued to practice my welding, and its slowly improving. A lot of the work still looks pretty ugly, but I did my first joint last night and I can reliably put down an ok line on a flat piece of steel. I've got to monkey with a bunch of settings around my TIG torch, but the fabrication series on youtube has been a big help and has answered a lot of questions I've had. I've got to grab a bit more Argon gas as I've only got a small tank, but mostly I think I just need some more time in the saddle.
IMG_0933[1].JPG

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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause » Sat Feb 08, 2020 7:26 pm

Just a quick update with regards to the welding. As per the photo below, I've had a marked increase in the quality of my welds. A number of things have helped, I'll note the following. First I've changed the nozzle on my tip. I am now using a size 12 with a gas diffuser, and the shielding from the Argon is much improved. It was quite cheap, I think 30$ for a whole set of attachments off of Amazon. Secondly, cleaning and weld preparation makes a huge difference, I'd been lazy about setup to start, but cleaning the piece with acetone, making sure everything is stable and well aligned really does make the welding easier. Thirdly, I was putting too much filler rod into my welds, it's more a case of pushing the puddle forward with the arc, adding some filler, removing the filler rod and then pushing the puddle forward again. Finally, more power is better, I had been nervous about the amperage setting to begin with, but putting it on low makes it harder to weld. You've got to have enough power to move steadily and quickly, if not you mostly heat the metal rather then weld it. I do have a question about the colour of the welds, I understand that for steel the weld should be basically shiny and steel coloured, I've got a bit of a rainbow going on and I'm wondering if its something I can get away with, and if not, how do I reduce the coloration?
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Richard Hull
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Re: Vacuum Chamber Construction

Post by Richard Hull » Sun Feb 09, 2020 5:03 am

Some coloration is unavoidable. forget it. I do hope you are aggressively wire brushing the weld once cooled. You will be amazed at what a heavy steel brushing will do for the appearance of the weld. Do it by hand or with a round brush in a power hand drill.

Good weld!.....Needs a heavy steel brushing to beautify it

"Learning by Doing".....It's The Only way!

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause » Thu Feb 13, 2020 4:05 am

Another practice weld was successfully completed tonight, and after seeing the colour of the weld after brushing I decided I was ok to move on to the actual welding of the chamber.
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The fit between the two pieces was tight enough that I didn't need to use any filler rod. It's not perfect, but I'm quite happy with how it turned out. I do need to find a small wire brush though as I wasn't able to fit the current one in the chamber to properly clean the weld.
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image1(1).jpeg (101.65 KiB) Viewed 2112 times

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Richard Hull
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Re: Vacuum Chamber Construction

Post by Richard Hull » Thu Feb 13, 2020 9:34 am

Smaller round wire brushes on a shaft will fit on a power drill and wire brush inside welds very well. Very tiny tightly confined welds can be brushed using a Dremel tool and its very small wire brush attachments.

Your interior weld is excellent looking. I deliberately machine all my fittings so that no form of wire feed is needed. Just simple fusion and a tiny bit of sacrificial lip or ledge supplies the filler metal by fusion to the joint. I hate wire filler feed and avoid it at all cost unless there is no work around.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause » Thu Feb 13, 2020 2:32 pm

I've ordered some small wire brushes for a few dollars, hopefully they'll fit, if not I'll look into finding a dremel. I do have a question about testing the soundness of the welds. I understand there are special dyes you can purchase to see if there are any cracks/leaks in the weld. Given the need for the welds to be airtight I was wondering if they were useful for checking for leaks or if it was better to troubleshoot once the whole system is hooked up to pumps.

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