Has anyone already built a welding purge chamber?
Dominik Meffert wrote 03/21/2020 at 07:18 • 0 pointsHi,
on my Wire 3D Printer project I noticed a problem with oxidation while I'm trying to print with welding wire and I'm thinking about using a purge chamber to keep the shielding gas consumption low. The machine should print for hours with minimal gas consumption to keep the price for the gas low.
Has anyone experience with such a chamber or already built one?
Would be glad if someone could help me :)
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Hi,
I added an inlet for shielding gas to my printer for further testing.
https://hackaday.io/project/169412-wire-3d-printer/log/175335-shielding-gas-again
Do you think a hole next to the nozzle is enough to benefit from shielding gas or do I need a proper shielding gas nozzle?
I'm thinking about sealing the printer on the sides so that the shielding gas which is heavyer than air gets collected in the printer until it reaches the top, if that works out.
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What is the problem with mounting, say, acrylic panels with some silicone sealer as the sidewalls of your Wire 3D printer, sealing incoming wires and filling all that chamber with CO2 or Ar? You could even leave top open if you use CO2, since it is heavier than air and would stay in chamber even with open top.
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Hi, thank you for telling me your experience :)
I think I will first try to work without a purge chamber until everything else works and will maybe later look at it again for increasing quality.
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Just a thought. Is the oxidisation occuring during the liquified metal printing or immediately afterwards? If it's afterwards you can always pickle with acid to remove it, providing it's ferrous. If it's during then is the shield gas enough of it flowing? Also if it's ferrous I don't think you need Argon or mix at all. Having enough 100% carbondioxide is better than relying on argon to counter oxidation problems because of amperage stability problems etc.
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Hi , Please don't take my following suggestion completely serious. I once many years ago sucessfully arc-welded a damaged car gasoline tank by keeping it filled with exhaust fumes via a tube from running motorcycle engine exhaust. As long as I could hear my motorcycle engine running I felt quite safe. I also waited until I could actually smell the exhaust fumes leaving the damage area before I started welding. I have always done seemingly crazy things but I'm also not dumb too and do my best to understand the risks.
Now just say, hypophetically your machine was outside running off a generator or in a place where monoxide fumes isn't a probem. You'd be throwing away the combustion gases. What's coming out the exhaust isn't Argon but it's not far different to CO2 shield gas, albeit a very humid version of it. With such an abundant supply of extra 'shield gas' help at all ? Or would the moisture content be too high?
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I am no expert in welding, but I would really think about doing something like this.
Since, in order to be effective, the shielding gas will have to remove most of the other gas in the area around the welding, it'll need a certain concentration.
If you let the gas flow right onto the welding tip, it'll understandably always have a high concentration there.
In a chamber however you would need to run a purging cycle for every time the chamber was opened, since then fresh air would mix into the chamber. Assuming you are using a noble gas, it's gonna be really happy to escape.
Since you'll still need to maintain a fairly high concentration of shield gas, you might have to spend a LOT of gas initially just to fill the chamber, and to ensure that no regular air is left inside...
I'd estimate that, at least for the first gas filling right after turning the machine on, you'll need to replace the entire volume of gas inside the purge chamber. Maybe that's still less than you'd need during the printing process, but I'd run the numbers.
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