Trying to find temporary Paint or Finish that can Wash off later

Discussion in 'General Experimental Aviation Questions' started by Rienk, May 8, 2014.

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  1. May 8, 2014 #1

    Rienk

    Rienk

    Rienk

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    Hey guys,
    I'm not sure where to post this question, but here goes.

    I borrowed a 3D scanner today, in the hopes of scanning our engine (and some of it's parts separately), so that we can do a 3D model of it, and use it to lay out our tuned intake and exhaust systems inside the cowl, and also design it around our engine mount and other stuff in there.

    We started a scan today, but the aluminum parts are too reflective to get a usable scan. Ideally, the parts need to be matt white or gray.
    Thus, we need to find some sort of sprayable material that - once we're done scanning - we can easily wash off somehow, without adversely affecting our parts.

    Does anyone know of such a material/product?
    I was thinking of something like Gouache? Need something - almost like PVA - that can rinse off.

    Any ideas?

    Thanks.
     
  2. May 8, 2014 #2

    JamesG

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    With aluminum you can pretty much use anything you want or is handy. Get a can of cheapo' spray paint in the color of your choice, and a can of "aircraft paint stripper" (which advises not to actually use it on aircraft, go figure). Or the equivalent, I see you are in California where everything causes cancer and is banned.
     
  3. May 8, 2014 #3

    Hot Wings

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    White spray hair coloring has been recommended for this. I haven't tried it with my scanner because I haven't found any yet so I can't say if it works or not. Powdered foot spray (don't get any that say they are colorless) works but my wife doesn't like the smell. The developer for dye penetrate crack detection is another option. Also the light in the room can cause problems if it's too bright or too close in color to the laser.
     
  4. May 8, 2014 #4

    Rienk

    Rienk

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    Thanks! You just reminded me of the color hair spray we used to use in the theatre!
    Not cheap, but it might get the job done, assuming I can find white or grey.

    But since we're going to do a lot of parts - it may be best to find other options.
    Thanks for the ideas, and any more that pop up.
     
  5. May 8, 2014 #5

    Rienk

    Rienk

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    That sounds a bit "iffy" to me... will it literally all come off, or will it end up with paint stuck in nooks and crannies.
    Eventually, we're going to GunKote the engine, and I don't want to have anything between that and the bare metal.
     
  6. May 8, 2014 #6

    Tiger Tim

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    How about locator paint? It's the stuff utilities use to mark where the gas lines and whatnot lie under your lawn and IIRC it's just a can of barely sticky powder.

    -Tim
     
  7. May 8, 2014 #7

    harrisonaero

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    Coat with talc. Google 3d scanner powder.
     
  8. May 8, 2014 #8

    Rienk

    Rienk

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    That's also a good idea.
    I just went to Walmart and bought a couple of cans of temporary hair spray (took me forever to find it, in the "celebration" department).
    I'll give it a try tomorrow.
    If it doesn't work, I might try this.
    Thanks!
     
  9. May 8, 2014 #9

    Rienk

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    The guy I borrowed the scanner from, has tried that often, but apparently it actually coats rough enough that the scanner picks it up and can make the scan grainy.
    Trying to find something that goes on smoother (flows).
    Thanks!
     
  10. May 8, 2014 #10
    Airshow pilots used to use a temporary paint when they got a one-off sponsorship for a particular show. I believe it washed off with plain water. Can't remember what it was called.
     
  11. May 8, 2014 #11

    Rienk

    Rienk

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    Maybe it was regular tempura paint (does the name come from the word "temporary"? I don't know).
    If I could spray it on, I might try it.
    If you recall/find the paint you refer to, please let me know.
    Thanks!
     
  12. May 8, 2014 #12

    Floydr92

    Floydr92

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    just use regular water based matt emulsion. the type you paint the walls in your house with. that will wash off with water easily.
     
  13. May 8, 2014 #13

    Rienk

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    I'm sorry, I'm not sure what you are referring to?
    To clarify, I need something that will wash off with water several days AFTER it has cured/dried.
     
  14. May 8, 2014 #14

    gtae07

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    I used to run the 3D scanner at work, and we used the athlete's foot spray. That stuff smells awful and you get funny looks when you and a coworker walk in and buy an armful of it, but it worked pretty well.

    You could also try childrens' washable craft paint or something.
     
  15. May 8, 2014 #15
    A quick duckduckgo search turned up this (plus several others) Duplicolor Car Art Paint Whether you want to add a cool flame design to your car or simply want to show support for your favorite football team on the weekend, Duplicolor car paint allows you to quickly add graphics to your car or create cool slogans. A special process, and use of specially designed pigments and ink powders, allows Duplicolor paint to pay it to dry in less than a minute. Also, the paint is very resistant to wind, rain and other elements. However, cleaning up the temporary paint is very easy and it can be quickly removed with a sponge a bucket of soap and water. It leaves no residue or film at at all, so the paint on your vehicle is left in the same condition as it was before the product was applied. Duplicolor Car Art Paint sells for about $6 per can, and comes in many popular colors, such as: black, white, red, blue, green and gold. You can find it in most car parts stores or at major retailers like Kmart or Wal-Mart.
     
  16. May 8, 2014 #16

    cheapracer

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    How about whiteboard markers, I use them all the time to mark out my aluminium pieces and simply wipe it off with a cloth later. Can be wiped off a week later no problem. It may even rinse off with water but i have never tried it.
     
  17. May 8, 2014 #17

    JamesG

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    whiteboard markers have the same drawback as the athletes foot powder, it will rub off easily with handling.

    No worse than any other coating, even powders. before coating they are going to solvent soak and clean the parts.

    I think you are overthinking the problem.
     
  18. May 8, 2014 #18

    Floydr92

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    Water based emulsion (dulux etc) will wash off years after it's dried. It's water based. That's what we use in the UK to paint interior walls. Surely the same where you are?

    When you mention the grainy surface...surely any surfaces that need to be smooth (cylinder walls etc) should be cut more precisely in cad once the part has been scanned in? I've not seen any 3d scanners good enough to duplicate a part accurately for something like engine use. So that should only leave the cast areas grainy, so not too much of a problem really?
     
  19. May 8, 2014 #19

    Rienk

    Rienk

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    Another great suggestion.
    I may actually try this one first.
     
  20. May 8, 2014 #20

    Rienk

    Rienk

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    I'm not sure why anyone would paint their interior walls with something that would wash off? I've had to clean walls to often after a toddler's crayon to think that house paint could/would do that... thus, I feel like I'm not understanding something.

    You're right about the issue regarding machined surfaces. We will actually have to recreate the part(s) in CAD (apparently a laborious and expensive process). We will need to recreate splines from the point cloud created. We are told that having a lot of clutter makes it hard to get accurate splines, lines and curves. But not having done this before, maybe we're being a bit paranoid (overthinking it, as JamesG says). All I know is that the scans didn't work yesterday on bare aluminum, and I want to minimize CAD cleanup. I just hate those "Whoops! Shouldn't have done that!" moments (also those, "I could have told you that!" moments, thus the request for help here)
     

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