Krylon Spray Paint Problem

Discussion in 'Low Power Rocketry (LPR)' started by Michael MacDonald, May 4, 2019.

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  1. Feb 20, 2020 #91

    Blast it Tom!

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    Thanks, samb. I guess it is what it is... I figure to wait another day or two, sand it but try not to go through the pink and maybe hit it again. If it wrinkles, I'll have to sand it and hope the clear coat glosses it up (and doesn't wrinkle!). But I'm like you, I shake like I'm trying pulverize the ball. Been that way since I was a kid.
     
  2. Feb 21, 2020 #92

    Blast it Tom!

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    Ok, I smoothed it out pretty well. But what will the clear coat do? Pigasus has printed paper covers for the "wings" and I was hoping to clear coat the whole rocket. I don't think wax would be good on paper... scares the clear coat will wrinkle, and after decals that would be a disaster. Or just don't clear coat?
     
  3. Feb 21, 2020 #93

    prfesser

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    Went back and read the entire thread, and I have one question and one suggestion.

    One poster claimed that Estes plastic nose cones give off formaldehyde. Formaldehyde is indeed one of the key ingredients in *phenolic* plastics, but that's the only plastic I know of that uses large amounts of formaldehyde. According to one publication, polypropylene---most large nose cones are made from it---gives off tiny amounts (less than 2 mg/1000 L of air) of formaldehyde during processing, but that's at elevated temperatures. So my question is: What kind of plastic is Estes nose cones made of? I'm pretty sure it's not phenolic; it's not brittle the way that solid phenolic is.

    Suggestion (if it's already posted elsewhere, sorry for the repetition): For better adhesion to plastics like polypropylene; after sanding, wash and rinse thoroughly, degrease/wipe down with isopropyl alcohol, and allow to dry thoroughly. Just before painting, sweep the surface with a propane torch. Not enough to melt it, of course, but the flame should sweep over the plastic. This bombards the surface with ions, making it chemically more reactive and more receptive to coatings. Paint as soon as practical after the torch has been turned off.

    Best -- Terry
     
  4. Feb 21, 2020 #94

    Blast it Tom!

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    Once again a treasure-trove of info in one post! But I'll just bang my cane on the floor and say "When I was young, we didn't have any of these plastic nose cones! Finishing balsa makes a man out of you!" upload_2020-2-21_10-44-29.gif

    (of course, the problems that led me to this thread were on a balsa and paper model, so...)
     
  5. Feb 25, 2020 #95

    SammyD

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    Thought I'd add my $.02 here as I've been accused of putting WAY too nice a finish on many of my rocket builds:

    What I think happened with your clearcoat was an incompatibility in paint types. Lacquer shot on top of cured enamel paint can "uncure" the enamel, making it soft or causing it to wrinkle. If you're using lacquer clearcoats, make sure you're using lacquer base coats. On the converse, enamel paint should not cause an "uncure" condition on lacquer basecoats however. Why? Think lacquer thinner; lacquer thinner is an additive in lacquer paint to cut the paint to a consistency that allows it to be sprayed from a can or a spray gun. It WILL uncure enamel paint - learned that from someone that painted show car finishes in my teen years.

    Even some enamel colors will cause the enamel below it to wrinkle on occasion - I believe it has something to do with the chemical additives in some colors that are not found in others, possibly a small amount of lacquer thinner?? Red and black Krylon enamel have given me that result on occasion. On a few instances I've had black paint crinkle problems going over earlier black enamel coats because I didn't let the first coats cure long enough. Other times a red going over a black base coast (where a color change on the model might be) has caused the problem, even not letting something like Bondo spot putty not cure fully under a primer coast can cause this condition.

    With that said, I've used Krylon exclusively for finishing rockets for a few reasons: it's not expensive, it's easy to "shoot", dries rapidly, easy to topcoat, wet-sands nicely, and can be componded and polished. The key to getting successive coats to adhere properly is letting the first coat dry completely. Read the instructions on the can here! Krylon, with their enamels anyway, suggest a first light coat, then successive light coats after 10 minutes, but before 2 or 4 hours. So that means, in theory, you can put as many coats on as you can in that window, but then put the work aside and let it dry.

    Some notes on spray tips with Krylon rattle cans: Find the cans with the separate WHITE colored nozzle in the red push-button (used to be called a "360 tip") as opposed to the YELLOW nozzle insert, or even worse, the large, white button with no separate spray nozzle. The former (white nozzle) gives a rectangular spray pattern that is FAR easier to control application of the paint in back and forth motions than the yellow nozzle, which shoots a round pattern making consistent application thickness nearly impossible, while the integrated nozzle in the oversized button is beyond useless! I went round and round with Krylon when they first introduced that yellow tip about 8 years ago because of its crappy application. Their reply: people (stupid ones I guess) were returning the cans because they thought the tip was defective and couldn't spray paint with it, so they dumbed the nozzle down... Bad idea, but the white nozzles can still be found. If you can't find the white nozzles, go to ACE Hardware. Their "ACE" brand spray paints are made for them by Krylon. The selection is not as extensive as you'll find at a Walmart, but the nozzles are right and the paint is Krylon, confirmed by Krylon in a phone call to them.

    Back to your finish on this rocket: Let the paint that's on the rocket now fully cure, then wet sand it again, dry the sanded paint with a towel and put it away for a day or so. Cutting the marred gloss topcoat with sandpaper will let the lower layers of the paint reach cure quicker, then go back and respray the model using two very light coats. Let them cure, then (without sanding) shoot two more light coats in a few days. If that works, let the model cure for a week, then do another low-grit wet sand, and try a few more light coats. You should be able to get the results you're after and correct your mistake.

    One final thought: If all else fails, you can spray the model down with Aircraft Grade paint stripper that can be found in most auto parts stores. and start over. It's not ideal, but I've done that on at least a 1/2 dozen models over the years. Sometimes the mistake is just too far down in the paint application (like uncured spot putty mentioned above) and it just won't cure, screwing up every attempt at the topcoat...

    Good luck!
     
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  6. Feb 25, 2020 #96

    SammyD

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    One last thought: I have NEVER and will NEVER use a clear topcoat on any paint I put on a rocket, something that is likely to see bangs, dings, nicks, scrapes, scratches, and the like. It's hard enough to repair a rocket that's been damaged in some way, then repair the paint too. If you've added clearcoat to the mix, it's just one more thing to repair. If the paint is done right, clearcoat is a waste of time in my opinion. I wet sand, then polish my rockets' paint until that paint looks like a mirror, and if that paint gets damaged, it's far easier to fix just the paint than it is to fix both paint AND clearcoat.....
     
  7. Feb 25, 2020 #97

    SammyD

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    See my reply in #95 above to a thread from last year (doh!). You'll find some helpful info in there. Compatibility is ALWAYS an issue, even more so if you rush the cure time. 30 minutes is definitely NOT enough time to cure for anything but a sandable primer coats.
     
  8. Feb 26, 2020 #98

    Blast it Tom!

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    Thanks, SammyD. My reason for adding clear coat of some variety is that decals are delicate, and clear coat both hides the film edges and protects the decal as well - going for that "painted on" look.

    with some judicious sanding/repainting, my Pigasus ended up fairly nice (IMHO), but certainly not show quality (well, maybe a 4H show?) - and I hope to someday be accused of putting 'way too nice of a finish on my rockets as well! Phooey on that "10 ft." rule! - at least for nice scale projects...
     
  9. Feb 27, 2020 #99

    58pan

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    Good to know, but now what do i do with all my Rustoleum 2X car.png
     
  10. Feb 27, 2020 #100

    Speaknoevil

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    Send them all to me. :music1:
     
  11. Feb 27, 2020 #101

    AfterBurners

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    Save yourself a lot headaches and extra work and go with Duplicolor primer and paint. Yes its more, but the primer sands like butter and the paint flows on. Just do it!
     
  12. Feb 27, 2020 #102

    Blast it Tom!

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    Sounds like a plan! Hadn't really thought of that before. Are there any issues with flexibility on paper tube (low power) type rockets, or is it about the same?
     
  13. Feb 27, 2020 #103

    AfterBurners

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    Not sure if you are directing your question to me and what I posted. No issues with flexibility on paper tubes. Use it all the time. If I'm painting large plastic nose cones I use this and then follow with primer

    https://www.autobodytoolmart.com//k...MI36TZ5a3y5wIVmY7ICh3uQQHwEAQYAiABEgIcbfD_BwE

    Also with Duplicolor you can adjust the nozzle to spray horizontal and vertical. Nozzles are high quality. You get a more uniform paint application verses other brands that spray in a "cone" type pattern. Duplicolor sprays in a "V" fan pattern so you can actually see more clearly what is being covered.
     
  14. Feb 27, 2020 #104

    Blast it Tom!

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    Well, yes, I was - I guess a quote may have helped! :oops:

    What you say makes an awful lot of sense. The adhesion promoter is expensive, but very likely a good step and it'll probably last half an eternity!
     
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  15. Feb 27, 2020 #105

    AfterBurners

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    Yeah I know its pretty pricey. Shop around you might be able to find it for a few dollars less at other retailers or online stores. Keep in mind you don't need to put it on thick. I use one light coat, just enough to cover the surface and let it dry for a few hours, but you can let it dry longer. From there I just spray my primer coat and go about the normal procedure for finishing. Great product.
     
  16. Feb 27, 2020 #106

    SCIGS30

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    This is why I pay a little more but stick with the old formula Krylon. It is a Acrylic Lacquer, can be recoated anytime, sands when dry and I have never had it crinkle like enamels. Also has the old style nozzles and sprays really nice. Downsides, not as glossy as enamels but will take any glossy clear coats with no issues. Also can be translucent so a white under coat really helps. Enamel paints crinkle for many reasons, some of the reasons are preventable and others are not.
     
  17. Feb 28, 2020 #107

    SCIGS30

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    This is why I like old formula Krylon, prime one day, next day shot Krylon grey, next day masked and shot Krylon Red. No recoat windows or chance of paint crinkle.
     

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  18. Feb 28, 2020 #108

    Blast it Tom!

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    Very nice, both of you. SCIGS30 & Afterburner. A few extra bucks to avoid a problem like the wrinkles is cheap insurance. It's not like I need 100 cans of the stuff!
     
  19. Feb 29, 2020 #109

    SammyD

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    That's EXACTLY what I was referring to with my "nozzles" discussions above. That spray pattern is crucial to getting even coats on the rocket! If you're using any sort of paint can that sprays a round spray pattern, all I can say is best of luck to you... The Krylon white nozzles do that vertical/horizontal spray pattern, and it makes all the difference in the world when trying to put paint down on a round (body tube) surface...
     
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  20. Feb 29, 2020 #110

    SammyD

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    Yep. Used them for years, and love the results. These are ALL Krylon painted, wet-sanded, then polished. NOTE: On the 3" scratch-built Patriot (next to an Estes Patriot), ALL colors are separately painted. The only decals on the 3" model are the "US ARMY" logos; on the Estes, all the black bands are decals (from Estes) - no black paint on it...


    DSCN0983.JPG DSCN0988.JPG DSCN1100.JPG DSCN1103.JPG DSCN2084.JPG DSCN2086.JPG
     
    Last edited: Mar 3, 2020
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  21. Feb 29, 2020 #111

    crossfire

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    I have been very happy with my paint jobs with Rust-Oleum 2X. I did have problem when I waited to long for 2nd coat. If 2nd coat is needed wait 24 hrs or more. I did 2nd coat about 30 minutes after 1st coat and it blistered. It seems if I apply 2nd coat with in 5 minutes its is fine
     
  22. Feb 29, 2020 #112

    Blast it Tom!

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    SammyD, those are some beautiful jobs! I hope I can approach that quality someday. I also have an airbrush - at one point in my life I was pretty handy with it.
     
  23. Mar 1, 2020 #113

    AfterBurners

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    Exactly!
     
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  24. Mar 1, 2020 #114

    AfterBurners

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    Beautiful work!!
     
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  25. Mar 1, 2020 #115

    SammyD

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    Thank you!
     

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