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Foxy Studio K33 0.18mm needle vs Standard IWATA 0.18mm

Discussion in 'Airbrushes' started by redcore, Jun 14, 2017.


  1. redcore

    redcore Gravity Guru

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    Yeah those pics are mine but i said to carlos in email that he can use them. But credit would be nice :)



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  2. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot! Very Likeable!

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    Something anyways. Well thats cool!... in a way
  3. palk

    palk Spider Splatterer

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    Yes you can use diamond paste but you need a lapidary wheel to get those flat surfaces. The hardened needle refines the grain structure of the metal letting them achieve that surface finish. If the needle is moderately magnetic, heat treated 440 stainless would be my suspected colporate for the needle there are better alloys but the range and the amount available would make it a logical choice
  4. Vladimir

    Vladimir Detail Decepticon! Very Likeable!

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    Do not use diamond polishing compounds for the needles! Though you can see polished surface by the eye, you've got some bad things to your needle. Small diamond particles cut into the metal and some of them remain there making your needle a sort of abrasive inside the nozzle. So no good news for diamond compounds. Use polishing compounds not containing diamond dust.
    I've polished with diamond pastes of various gradations for a start, but soon after was told what I had with them. So I switched for another type of polishing compound.
  5. palk

    palk Spider Splatterer

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    You should have sold the pic,s for 3 needles those things are expensive to rich for my blood, Ill roll my own at that price (smokers joke)
  6. palk

    palk Spider Splatterer

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    You are correct the diamond dust will impregnate soft substrates or if you apply too much pressure, but hardened steels (fine grained) are far less prone to this and a quick rub on floated made glass will tell you if this is the case. I have not tested it on 316 Stainless(typical material for needles) but I have both, so I will give it a go.
    I use to polish plastic injection moulds to a mirror finish.
    The most time I spent on 1 mould polishing it was 60 hours after 2 days I begged :tired:to take a day off it and do some machining.
    I swear, to this day that mould block was looking at me the whole time I was away from it.:Dlollol
    Last edited: Nov 26, 2017
  7. nickkat1

    nickkat1 Gravity Guru

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    I'm not sure as to what you're trying to address? I am referring to polishing a needle to prevent tip dry

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  8. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot! Very Likeable!

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    Obviously the way you polish works, lots of people do it and theres nothing wrong with it.
    That said
    If you wanted to produce the needles and keep your taper straight, ( without curving the angle) A lapidary (and /or very controlled electropolishing) would be optimal.

    316 can't be hardened by heat treating so I see why this was your first thought.
    The k33 is Kolsterized, which is suitable for hardening austenitic stainless. So it's probably still 304 or 316 or the like.
    I suspect kolsterizing is just the brand name for a specific way of Plasma or ion nitriding.


    True with the embedded particles and it's an issue with large grits and soft metals but...
    No matter what polishing compound you use , If the grit is harder than the metal, you can and up with embedded particles. It's no different using aluminum oxide or cerium or any of the other common compounds. The harder the surface being polished the less its an issue.

    If the grit you're using is softer than than the metal then you're technically burnishing which might be better for these...I have no idea.

    Lot's of mechanical parts are polished using all sorts of grits without causing undue wear. I personally wouldn't hesitate to use diamond as opposed to any other option. Your needle is already far harder than the nozzle and will wear the nozzle at some point no matter what. I don't think a couple of microscopic 5000+ grit diamond particles will make a lot of difference. Titanium dioxide pigments in your paint are harder than the metals and a larger grit size than the diamond paste. So they cause a worse effect than some embedded superfine diamond grit I would think.
    If the surface has to be totally pure it's usually electropolished.

    Just my take on these.
    Last edited: Nov 26, 2017
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  9. nickkat1

    nickkat1 Gravity Guru

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    I understand that a different mechanism would have to be used to change the geometry of the point. That goes without saying, I think once the subject goes into imbedded particles we've crossed a point which I think is somewhat comical!

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  10. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot! Very Likeable!

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    Even to totally preserve the geometry.
    But yes I agree most of this is comparable to figuring out which scope you should use on your NERF gun
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  11. nickkat1

    nickkat1 Gravity Guru

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    bahahahahahahahahahahaha....

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  12. Vladimir

    Vladimir Detail Decepticon! Very Likeable!

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    Good to know!:) But still, I've found good way to polish without diamonds and will be doing that;) The needles look like mirror with any shape I need for them.
    I don't have any access to electro polishing, actually it's for the first time I've heard about it:) At the time sandpapers and polishing compound is always at home.
  13. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot! Very Likeable!

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    Diamond is probably overkill for any unhardened needle, since just about any compound should work. It is easiest to get in superfine grits though. So it makes a good choice. Bottom line, In my opinion none of you guys are polishing in any way I personally would think is wrong. All of you have more knowledge and experience than I do about it when applied to airbrush needles.
    Electropolishing is what they use for hypodermic needles and such.
    It's kind of like reverse electroplating. Just have to keep the electrolyte really agitated. Then depending on how much current you use it removes sharp points of a certain size so you can get a very specific surface quality. I'm working on a super cheap accessible way to do it at home and use it on these needles , only because it would actually be the easiest possible way to polish a needle without changing the geometry or using any skill.
    Last edited: Nov 26, 2017
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  14. palk

    palk Spider Splatterer

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    Robbyrockett2,
    If you are telling me " The k33 is Kolsterized,"
    Then I am not going to say they are not I am only guessing from experience
    But surface hardening a tapered needle is not what I would do. The biggest down side would be once the tip breaks off there is no repair unless you regrind and re harden
    The upside to Kolsterizing would be maintaining the corrosion resistance of 316
    The nice radius needle point suggests some electropolishing
    Last edited: Nov 26, 2017
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  15. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot! Very Likeable!

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    It's what they claim on their website. As far as I know yeah you're right there is no practical way to repair a k33. I haven't heard of anyone breaking one yet though. Whether it's due to them being tough or due to the people having them being careful....I have no idea.
  16. palk

    palk Spider Splatterer

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    @ 83 euro there is good reason to be careful, I have not paid that for an airbrush Yet
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  17. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot! Very Likeable!

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    You aint kidding!
    Yeah I agree with you too, If I were designing a hardened needle and knew it would be kept relatively clean after use, I might go a different route than kolsterized 316. IDK guess it would depend more on whether I was designing it for the masses or actually just making it for myself...,
  18. palk

    palk Spider Splatterer

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    I recently polished my chinese brush needle and found pits in the surface from making to large of step from the previous grit size when they made it so it is back to 1000 grit and up I go again If I end up off center then its into tool and cutter grinder
  19. palk

    palk Spider Splatterer

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    I understand the price, the production strategy would be place an order with tooling company then off the to the heat treater back to the tool company for assessment then off to the electro polisher back to the toolmaker then shipment to Foxy that's how it would be in OZ . Very few companies would have all those trades under one roof who would be interested in doing needles
    Before leaving the company I worked for I purchased a Electro Discharge Machine that had an electropolishing feature, Still figuring it out 9 months later
  20. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot! Very Likeable!

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    Some of my chinese needles actually have inclusions in the metal and aren't possible to polish without pits.
    Yeah the price is undoubtedly due to sending batches to several subcontractors before it's complete and you could't have it done to a small quantity yourself for even close to the price of purchasing one or three.

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