Best way to clean frosted ultra detail model for painting?

Discussion in 'Finishing Techniques' started by ScottPBrown, Oct 4, 2015.

  1. ScottPBrown
    ScottPBrown Member
    Hello,
    I have read in magazines that the printed frosted ultra detail models which I intend to paint need to be "cleaned" of the wax support material first; or the paint will not adhere.
    My models are N scale train models, for this discussion; so there will be priming, painting and decaling to complete the model. ( as well as adding some extra details such as wire "grab" railing, etc)
    I have read that one person advocates "soaking" in Bestine- a rubber glue thinner. If so- how long is the "soak", and will excessive cleaner damage/soften the FUD plastic/acrylic?
    How long do I let the model "dry" of such cleaning before I can begin painting it?
    Another person states to use "Goo-Gone".
    And yet another states to use acetone......
    What would the Shapeways experts and community recommend for this, as I can find nothing on Shapeways site addressing this issue.

    The models I bought appear to be excellent, I sure would hate to damage/dissolve one of them in my own search for the answer....

    Thanks,
    Scott P Brown
     
    00dwkr likes this.
  2. mkroeker
    mkroeker Well-Known Member
    I'd try dishwashing liquid first - unless you want to achieve the white, crackled surface that solvents like bestine (heptane) create, which some say aids in their painting.
     
  3. sbhunterca
    sbhunterca Well-Known Member
    I use 95% isopropyl alcohol, which works very well, unless a model is caked with heavy, hard globs of support wax, as is the case on one I'm dealing with at the moment.

    Steve Hunter
     
  4. sbhunterca
    sbhunterca Well-Known Member
    I just checked several chemical compatibility charts for acrylic... acetone is listed as incompatible and "will" damage surfaces, hexane (Bestine) is listed as incompatible and "may" damage acrylic. This is what causes the sought- after white finish...

    I did try an acetone based solvent on some of the hard, immovable wax crust, wiping it off almost immediately, and found it softens the wax enough that I can scrape it off a little at a time. Would I soak a model in it? Not in this lifetime!

    Steve Hunter
     
  5. I use acetone all the time to clean my FUD parts.

    To date, a quick submerging in acetone for about 3 minutes has cleaned every part I have received from Shapeways. Then just pull it out and let it air dry for about 1 minute and you are ready to paint. It definitely gives you that "frosted" surface, but this helps with paint adhesion.

    Early on, I did perform a test to see if the acetone would damage the material. I took a very small part with many very thin wire structures and submerged it in acetone for 15 minutes. The part came out a little rubbery in the wire areas but was still usable after drying. This is why I opt for the 3 minute submersion.

    TDR Innovations
     
    phmccray likes this.
  6. dcyale
    dcyale Well-Known Member
  7. he6agon
    he6agon Well-Known Member
    When you soak the parts in either 91% isopropyl alcohol, Bestine or acetone, is any scrubbing required to clean the parts or is the soak effective by itself? If I use 91% isopropyl alcohol, how long should I soak the parts? What about Bestine?
     
  8. he6agon
    he6agon Well-Known Member
    I tried 10, 20 and 30 minute soaks in Bestine to clean a number of FUD and FXD parts recently with poor results. The waxy material began to be removed from the models, but because of the obvious etching/whitening effect the solvent was having on the parts I was hesitant to take the process much farther.

    Next I tried soaking some medium size FUD parts (1" x 1.5" x 1", 0.04" wall thickness) and some small FXD parts in 91% isopropyl alcohol based on the recommendations in this thread. I assumed that since the alcohol didn't have an apparent negative effect on acrylic and that alcohol must certainly be a less aggressive solvent than Bestine a longer soak would be required. Unfortunately I experienced what can only be characterized as disastrous results. A three hour soak not only warped the parts beyond recognition, it shrank them slightly as well. I was able to flatten the small FXD parts somewhat, but not enough to be usable. The alcohol seemed to make the parts brittle as well, which caused a crack to form as I placed a tight fitting part on the model for which it was designed (and which it fit perfectly prior to the soak). So needless to say, I'm not going to use alcohol again, though to be fair it effectively cleaned the parts of waxy residue that Bestine didn't budge. Perhaps a very short soak could remove the waxy material without damaging the plastic or shrinking it. I'm not going to find out.

    I tried cleaning some other similar parts with a three minute soak in acetone (again, recommended upthread) and others with a 30 minute soak in Simple Green household degreaser. Because of the problem I had with shrinkage, I measured each part in all dimensions to determine what if any shrinkage occurred (I measured none). Both acetone and Simple Green did the job, but Simple Green stripped the parts bare and maintained the transparent quality of the parts.

    I tried another set of parts using only a spray of Simple Green and light scrubbing with a toothbrush, followed by a scrubbing with dish detergent (Dawn brand) and a rinse under cool water. Total cleaning time <2 minutes. Again, the results were like the 30 minute soak in Simple Green. Very pleased with the stuff.

    I'm curious to hear if anyone else has tried degreasers or surfactants on prints from Shapeways and what results they saw.
     
    Model_Monkey and 00dwkr like this.
  9. sbhunterca
    sbhunterca Well-Known Member
    Yes, three hours in alcohol is far too long. I use no longer than a five minute soak with no damage, but lately I'm finding hard, crusty wax residue that is a bear to remove.

    I see that Simple Green is sold at Canadian Tire stores, so I'll pick some up and give it a good try on the latest partially cleaned model and a batch that are ordered, but won't arrive until late November. I'll report back...

    Steve Hunter
     
    00dwkr likes this.
  10. he6agon
    he6agon Well-Known Member
    The latest issue I have is a pair of parts with one side that is sticky like honey or uncured resin. These two parts were part of an order of six parts and they both showed up "complete" while the others were still shown "processing," which leads me to believe they were printed at the same time in the same batch. Anyway, cleaning these parts with Simple Green was as successful as any other parts, but the sticky sides remain sticky no matter what I do. If it is incured resin, I have no idea how to fix that. At this point I'd just like the parts replaced. They came out fine last time and would have been okay if I hadn't warped them in the alcohol.
     
    00dwkr likes this.
  11. sbhunterca
    sbhunterca Well-Known Member
    For the uncured parts, definitely contact Customer Service as they should never have left the factory like that. Send a photo or two if possible. They'll get you fixed up pretty fast.

    Steve Hunter
     
  12. he6agon
    he6agon Well-Known Member
    Thanks. I already sent a message to customer service but I will be sure to take some photos and send them along, too.
     
  13. sbhunterca
    sbhunterca Well-Known Member
    OK, I, too, have tried Simple Green and I love it!

    I soaked a problem model with hard, crusty wax for twenty minutes, followed by a gentle scrub with a soft toothbrush, and was very pleased with the results. And at $5.99 CDN for a 650 ml spray bottle at my local Canadian Tire store, it's easy and cheap to buy.

    No more alcohol for me...

    Thankyou, he6agon, for discovering this stuff!

    Steve Hunter
     
  14. Leeshapes
    Leeshapes Member
    Reviving an old thread! After soaking your model in Simple Green and letting it dry completely - is it safe to apply primer, or should the model be washed again with soap after Simple Green? Thank you!
     
    00dwkr likes this.
  15. he6agon
    he6agon Well-Known Member
    I just wash it with soap and water after the Simple Green, then dry it with compressed air. Once it's dry it's safe to prime. I've been using Tamiya Fine Surface primer for a couple years now without any problems.
     
    00dwkr likes this.
  16. Model_Monkey
    Model_Monkey Well-Known Member
    Concur with Ryan's comments.

    I, too, recommend using only mild, water-based cleaners like "Dawn", "Fairy", "Neophos", "Sun", "Sunlight", "Joy", or "Vim" dishwashing liquid, baby shampoo (no conditioner), or "Simple Green", all diluted in water. No customer of mine has reported any problems with these cleaners. I have used "Dawn" and "Simple Green" with no problems.

    Customers have reported problems with acetone, Bestine, acetate, and methyl ethyl ketone (a strong chemical sometimes used by modelers to thin paint for airbrushing). Customers said that these chemicals attacked and damaged FUD and/or FXD. Good to know isopropyl alcohol harms the plastic, too. Thanks, Ryan, for the headsup.

    I recommend painting very soon after cleaning. Based on customer feedback, FUD/FXD, once cleaned of its protective oil covering, may be sensitive to prolonged oxygen exposure. SW (New York) has been investigating this.
     
    00dwkr likes this.