Pirani Filament Repair

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
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Angelo Gomes
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Pirani Filament Repair

Post by Angelo Gomes » Tue Aug 22, 2017 10:56 am

I was wondering here how hard is to replace/repair a broken Pirani Filament.

Does anyone has experience on this ?



Angelo.

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Dennis P Brown
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Re: Pirani Filament Repair

Post by Dennis P Brown » Tue Aug 22, 2017 12:50 pm

First, you need to follow the rules on name usage before posting. Second, those devices are too cheap to care about fixing.

Angelo Gomes
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Re: Pirani Filament Repair

Post by Angelo Gomes » Tue Aug 22, 2017 5:52 pm

Hi, only now I read that I need to signup/login with Real first and Last name.

I tried to modify that on Control Panel, but it seems that I need to create another account.

About these devices to be too cheap, I strongly disagree. It depends on if you have funds enough to buy a new one or not. Ok, you can say that we can purchase on ebay, but there is not guarantee they will arrive working.

Rex Allers
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Re: Pirani Filament Repair

Post by Rex Allers » Tue Aug 22, 2017 8:54 pm

I tried to modify that on Control Panel, but it seems that I need to create another account.
I changed mine a while back when the forum changed to requiring full name. I just tried it and it seems to work, though I changed back before logging out.

See the post I just made in the New User Chat area.
Rex Allers

ian_krase
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Re: Pirani Filament Repair

Post by ian_krase » Wed Aug 23, 2017 8:38 am

More to the point I don't think that this sort of thing is terribly... repairable. They don't open up. If you want to try, you might look at some of the threads (like mine) about spot-welding filaments.

(On the other hand, nude ion gauges are a different story. They have removable filaments.)

Angelo Gomes
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Re: Pirani Filament Repair

Post by Angelo Gomes » Wed Aug 23, 2017 11:59 am

Hi, just to let you know that I will search again how to fix the login/signup problem.

Hi Ian, thank you for your message. Yes, yesterday I looked for our Spot Welding machine and found it (working !!!). I bought last night some tungsten filaments 0.02mm and 0.05mm from aliexpress and as soon they arrive, I will try to do some tests as I have two piranis with broken filaments here. I think the problem will be to make a 40 ohms coil with W wires.

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Dennis P Brown
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Re: Pirani Filament Repair

Post by Dennis P Brown » Wed Aug 23, 2017 12:56 pm

I found some Pirani gauges for $80 and less; not cheap but as vacuum equipment goes, really not all that expensive. Considering the cost of a spot welder and the work involved, and issues to make a new filament that will allow for your system to remain calibrated over its required range I would think those would be a challenge; but you know your limits and needs. Unless I had a special requirement, I just use a cheap thermo-couple gauge but it appears to work very accurately in the 3 - 30 micron range (a joke but outside those ranges) and that is all I care about since that covers my fusor very well; your needs may require a larger range and better calibration. In any case, your method of repair and results are of good interest here and you might want to post with some pics as you get results. Best of luck. I have read how a person used some small bulbs (with filaments) as a Pirani gauge tubes - just a thought on a cheap alternative, maybe.

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