Black dye WSF & PWSF

Discussion in 'Finishing Techniques' started by tomrust, Dec 17, 2012.

  1. tomrust
    tomrust New Member
    We've been unhappy with the general evenness & surface quality of the black SF material. 1/2 of our customers want black products to match their phones, so it's become a high priority to try to find a better black material.
    We also REALLY like the surface quality of the PWSF material, and so do our customers. Its smoother & has less of a gritty feel.

    So we've started running some tests of dyes.
    We first tried Rit dye Black, using a formula of 8 cups water, an 8 oz liquid bottle, and 8 teaspoons of vinegar. We heated to 60C (that was the recommended temp) and immersed parts for up to 6 hours. The WSF got quite dark, but always had a bluish cast - not a true black. PWSF was much worse - a nice navy blue but NOT black.

    Today we tried iDye Poly from Jacquard Products in Healsburg, CA, bought at a local Joanne's Fabrics. About $4 per packet, which includes the powder dye & the brightener. Again the formula was poured into 8 cups water - just a bit more than needed to cover the parts

    This we ran at 80C for 1 hour on a WSF, and 40m on 2 PWSF parts. The photo of the result is enclosed - the PWSF parts on the left, the WSF on the right.
    You may need to adjust the brightness to see the engraved Nautlius logo. But we were reasonably pleased with these initial results.

    One issue - for some reason the PWSF parts had a buildup of dye on the surface after removal. Hot water and detergent cleaned it off nicely, no change to the color. I spoke with Monty Witherby (sp?) at the company who recommended running at 100C (keep it at boiling) but we kept it below 80C as the data sheets recommended 80C max temps, even though the softening point of the nylon is much higher.

    Note the WSF & pWSF are just slightly less dense than water, so parts float (barely). We stirred the baths every 5-10m, & had the logo faced down. Yet all sides were covered quite evenly.
    dyepix.jpg
     
  2. TOM_TOM_TOM
    TOM_TOM_TOM Well-Known Member
    I also did my own tests. Minimum boil time was 1 hour. I always boiled. It makes the plastic softer though, but I think shapeways, sculpteo, and materialise all boil too.

    Acid dye needs PH 5.0 while Lanaset Dye needs PH 4.5. The Acid and Lanaset turned out the best, but they still were not exactly black. I used 40mL/1L of vinegar (5%) for Lanaset, and 15mL/1L for the Acid. I tried the Acid dye again with 40mL/1L but this turned out red.

    I made a mistake in the iDye Poly + clearcoat label. This was 2 hours, not 1 hour, and it was much darker than the 1 hour, but it uneven with patches of red. The 1 hour was clearly reddish. The Lanaset is slightly blue. The Acid was more neutral, but a bit gray.

    I may just change my desire for black and go with gray or some other color that doesn't give customers an expectation.

    adding a clear coat really darkens the color.

    _DSC7098-1.jpg
     
    Last edited: Dec 18, 2012
  3. tomrust
    tomrust New Member
    Great work. Interesting results. We used only 8 cups of water and the entire packet of dye plus brightener. Also a different (lower) temperature, although I would think it should not make that much difference. However, the tech person at Jacquard indicated the process involved swelling the fibers with the increased temperature, so its possible there may be some temperature effect.
    How much water did you use for your iPoly tests?

    What I noticed as the dying progressed was the color was initially greenish, then turned grey then completely black.

    The PWSF versions after drying had the look and feel similar to black leather. The WSF versions just looked VERY black, almost perfect blackbody.
     
  4. stannum
    stannum Well-Known Member
    How deep into the item is the dye penetrating? There are some white areas in the top right item. Lots of sanding to fit the part? Or normal wear?
     
  5. tomrust
    tomrust New Member
    Another thing Im wondering is if we are using a different dye from Jacquard - the tag on the envelope says BLACK JID1454. Which one did you use?
    Im running another test now, and after only 20m it looks quite dark already.
     
  6. tomrust
    tomrust New Member
    In running another test, started by boiling the dye. After 30m checked. Interestingly, i am seeing the reddish tint thomas huang saw.
    Two possibilities i can think of.
    One- not fresh batch dye. Left over from last run.
    Two- high temps swell the nylon particles so much they close off too much area, so dye doesn't penetrate. The surface seemed shinier than the previous run
    So seems plausible.

    Have put back in bath and am running at low (60c) temp.
     
  7. tomrust
    tomrust New Member
    More time only made it worse! More reddish.
    Will try fresh batch low temps tomorrow.
     
  8. TOM_TOM_TOM
    TOM_TOM_TOM Well-Known Member
    I used just 1/5 of the iDye Poly with 1L of water. It was boiling for 1 hour. That resulted in the red. A similar mixture with 2 hours resulted in a darker red, but still red. I'm a bit surprised you were able to get black with just 60C, although I'm not sure whether using the whole packet of dye made that difference. I won't be able to make more tests until next year, but I would be interested in seeing your results. It sounds difficult to get the same results everytime without knowing what factors affect the outcome.
     
  9. tomrust
    tomrust New Member
    I spoke with Monty again. He indicated it was likely that the bath needs to be fresh. Apparently different sized molecules deposit at different times. Once depleted the color balance shifts.
    He also recommended trying their acid dye 639.
    He's also willing to run tests for us to ensure the best results!
    Nice to offer. Won't happen till after new year though they're shutting down after tomorrow.
    Maybe Shapeways can provide some test pieces too?
     
  10. tomrust
    tomrust New Member
    So I ran another batch of dye, this time fresh made, kept temps 60-70c, ran for 40m. I used one pwsf case & the two cases that came out reddish before] to try to get them blacker.
    The virgin case came out nicely black as in the first test. The other two (right side pix) got a bit darker, but still reddish & more glossy.
    So fresh dye is key, temps also.
    2012-12-19_14-21-58_648.jpg
     
  11. woody64
    woody64 Well-Known Member
    I have to agree a pWSF with a black glossy surface would be a great push for selling ...
    Woody64
     
  12. TOM_TOM_TOM
    TOM_TOM_TOM Well-Known Member
    Is the black you're getting at 60-70C really black, or does it have a slight tint? On my screen, your photo looks a bit purple, but this could just be the color balance of your photo.

    It would be interesting to test the acid dye at a lower temperature again, but i won't be able to do this until the middle of January when I come back.
     
  13. tomrust
    tomrust New Member
    I see what you mean about the purple tint. May be the lighting/camera. In sunlight it looks quite black. There is a glossy reflection that changes depending on the lighting.

    We've actually gotten to rather like the dark red glossy tint on the "failed " tests.
    Has a rusty steampunk look.
    The feel of the pwsf dyed cases is very different too. Rather like a polished hard shoe leather.
     
  14. TOM_TOM_TOM
    TOM_TOM_TOM Well-Known Member
    Hi Tomrust,
    Any news about the acid dye? Have you tried any other temperature, pH values with the iDye Poly?
     
  15. tomrust
    tomrust New Member
    Not yet. Our local supplier didn't have the acid dye but plenty of ipoly dye.

    We've been communicating with EOS lately- maker of machines & materials we believe
    Shapeways uses. EOS has a black material similar to the white. Im surprised Shapeways
    Doesn't use it.
    Also the alumide is a lot cheaper than the wsf, yet Shapeways charges more. Could be a demand issue.
    I also tried to get Shapeways to provide some samples for Jacquard to run dye tests. They want us to pay for them.
    Im frustrated as it feels like we're trying to help solve their problem but not getting any support
     
  16. TOM_TOM_TOM
    TOM_TOM_TOM Well-Known Member
    I spoke with someone at Jaquard technical department, and he told me to always use rolling boil for polymide. He also recommended using 10% powder by mass, so my 60g (60m^3) part would use 6g of powder, or about half of the iDye packet. He said to me that the iDye Poly would work better than the Acid Dye and not to bother trying the iDye Natural.

    The shop which sold me the powder in Germany was run by a guy who said he had a lot of experience in the textile industry, and said kind of the opposite, that the Acid Dye would be better than the iDye Poly.

    I don't know who is right.

    And I'm not sure why you were able to get a better result at 60-70C while the others are saying to use rolling boil.

    Previously, I used just 1/5th of the packet on my 60g part, the iDye Poly which came out reddish, and the Acid Dye a bit gray. .I just have half a packet of each left, so I may try using them all at one time with rolling boil, but didn't you try this already before?

    Where did you hear that the Alumide is cheaper than PA? I was told by the local printers that Alumide is at least 30% more expensive than PA. Their quote was 20-30% more.

    They said they didn't like many different materials in the machines because they have to clean it out well before changing materials. Sometimes the next material gets contaminated with the previous one, and ruins the print.
     
  17. Mhagan
    Mhagan New Member
    We have seen the EOS black and it isn't nearly dark enough. Rest assured that Shapeways is working hard on this problem. :)
     
    Last edited by a moderator: Jan 11, 2013
  18. natalia
    natalia New Member
    Hi Tom,

    I know Mitchell and Christel have been in touch from Customer Service, we'll keep everyone posted on what's happening.

    As Matthew said above, we do know about EOS black powder, its just not dark enough.

    We do really appreciate your testing, and everyone who experiments with all of our materials! Please keep posting your experiments and results, and know that we are doing a lot of R&D too!

    Best,
    Natalia
     
  19. karwaing
    karwaing New Member
    Even if the EOS black is not a dark black, I think you should make it available. Something like a dark grey is a very useful colour, and for my purposes preferable to a dyed black, even if the dyed BSF is a darker black.

    If it's a marketing thing, you could just call it Grey Strong Flexible. It'd become my default material of choice. Or Polished Grey Strong Flexible!
     
    Last edited: Jun 18, 2013
  20. TOM_TOM_TOM
    TOM_TOM_TOM Well-Known Member
    I've heard that Jacquard is going to have a gunmetal iDye poly soon. I'll be trying this.