Vacuum Chamber Construction

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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause »

I've now completed machining of the ports for the vacuum chamber. Up next is an order to lds vacuum for the remaining parts I need and some practice welding.
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Re: Vacuum Chamber Construction

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That is a lot of holes.
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Richard Hull
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Re: Vacuum Chamber Construction

Post by Richard Hull »

I mentioned that before above....An awfully hole filled chamber. Lots of CF stubs and lots of blank offs unless you are shooting for ion guns aplenty. At least he won't be at a loss for hassle free "add ons", if needed, in future.

On page two Nicolas gives a full, optimistic, listing of what is planned for each port. Until they are all in place, that means blank offs during early work.

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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
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Re: Vacuum Chamber Construction

Post by ian_krase »

In the excellent but extremely grognardy and complicated Kerbal Space Program mod KSP Interstellar, we see this fusion reactor, which appears to be a fusor-type reactor with ion guns.

Image

This makes me think of it.
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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause »

While I source the final vacuum components for my chamber I figured I could work a bit on the pressure sensor. I've got a vacuum thermocouple gauge, and a spare Tiva C series board lying around. I figured I would use one to monitor the other, I've been planning on picking up Forth for awhile and this seemed like a good project to start with. Mecrisp is a publicly available version that supports my board so I'm working on getting a connection made to the board.
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Nicolas Krause
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Re: Vacuum Chamber Construction

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This is an end of summer update. My purchase from LDS vacuum arrived at the end of July, and I now have the necessary hardware to complete the vacuum chamber. While I had intended to complete the welding by the end of August, getting setup for TIG welding has taken longer than anticipated (as always seems to be the case). The local makerspace does not have a TIG welder, and I've had to turn to other means. I've purchased a small TIG machine on Amazon from HitBox, and while it turns on, sourcing all the other components, such as TIG electrodes, a small bottle of Argon gas, a regulator, 220V dryer plug adapter, has been an education in and of itself. Its taken me the whole month of August to obtain all the bits, sharpen the electrodes, find a bottle supplier, get the bottle filled etc... I'm returning to school this Tuesday and will have to pack away the hardware for the summer. This means I'll likely return to work on my simulation when time allows, and hopefully at Christmas I'll be able to find some time to work on welding of the chamber. I'll be on a co-op term from January to April so ideally I'll be able to complete the chamber after work hours during the winter.
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Re: Vacuum Chamber Construction

Post by ian_krase »

Where are you doing your welding? Do you own a house with a garage, or do it somewhere else, or what?
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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause »

I don't own a house unfortunately, I had planned on appropriating the dryer plugin in my parent's laundry room and running an extension cable outside through a window so I didn't have to worry about the fumes/gas. The welding machine I've bought is quite small and portable so it shouldn't cause too much of an issue. If I'm welding in the winter I'll look at heading to the local makerspace with my setup as I believe they're wired for 220v and have a large ventilated bay.
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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause »

Just a short update, I've managed to get the mecrisp-stellaris version of forth loaded onto my board and am now monkeying around with the language in my spare time!
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Re: Vacuum Chamber Construction

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After completing another semester of school in Victoria, I'm now on an 8 month co-op in Edmonton. I've joined the local makerspace and setup my TIG welder for the first time tonight. I'm currently practicing on some scraps of steel I've got lying around, and boy do I need it! I'll probably keep practicing until I feel comfortable and then go ahead and start welding the components of my vacuum chamber. At the moment I've got a lot to learn, and I'm just trying to get better at controlling the puddle.
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Richard Hull
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Re: Vacuum Chamber Construction

Post by Richard Hull »

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Vacuum Chamber Construction

Post by John Futter »

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

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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.
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Rich Feldman
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Re: Vacuum Chamber Construction

Post by Rich Feldman »

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

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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.
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Nicolas Krause
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Re: Vacuum Chamber Construction

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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

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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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause »

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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Richard Hull
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Re: Vacuum Chamber Construction

Post by Richard Hull »

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause »

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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Richard Hull
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Re: Vacuum Chamber Construction

Post by Richard Hull »

I tested my hemispheres using a rubber gasket on an old bell jar plate. Check the construction FAQs for my fusor II images. You have so many ports on each hemisphere it would be tough. You would have to blank of all on each hemisphere.

viewtopic.php?f=24&t=13053

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
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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause »

Welding continues steadily, I've nearly completed one hemisphere. The welds need to be cleaned and checked for leaks, and one its quite messy, I might use a dremel to smooth it out. Other than that, simply running out of Argon is what halted progress today.
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Richard Hull
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Re: Vacuum Chamber Construction

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The good news is argon is extremely inexpensive. You must have a small tank. Mine is full sized and I have had it now for 20 years and used very little of it. I fear that when I need a refill, they will note the tank pressure inspection is out of date and charge me an inspection fee in addition to the argon. This is a penalty often impressed upon a small use welder. Big shops never suffer this as they exchange frequently.

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
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Nicolas Krause
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Re: Vacuum Chamber Construction

Post by Nicolas Krause »

I've nearly completed all the welding on my chamber. A single large weld remains, but having run out of time this evening it will have to wait.
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Richard Hull
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Re: Vacuum Chamber Construction

Post by Richard Hull »

Good golly miss Molly! Did you get a sunburn doing all of this welding?
If not, you did good....

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
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