Author Topic: Problem with powder clear over decal...  (Read 2318 times)

Justus

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Problem with powder clear over decal...
« on: February 25, 2015, 02:16:04 PM »
It looks like my clear coat picked up some of the base coat, and I lost all the color detail in my decal. Pictures are worth a thousand words, so here goes:

Before clear coat:


After:



I'm using Columbia coatings dormant sparkle red as the base coat in those pictures, followed by Columbia coatings gloss clear as the clear coat.  I did a full cure on the base coat, 15 minutes at 375, then apply the decal and let it dry overnight. Then I applied the clear coat, and did another full cure, 15 minutes at 375. I have no idea what went wrong. Any suggestions?

irmcdermott

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Re: Problem with powder clear over decal...
« Reply #1 on: February 25, 2015, 03:42:04 PM »
What is that decal printed on/how was is printed (laserjet/inkjet)?

Justus

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Re: Problem with powder clear over decal...
« Reply #2 on: February 25, 2015, 04:28:59 PM »
Papilio white bake-on laser decal paper...  with a color laser printer.

Guys over on a powdercoat forum say it's because the dormant colors pull through when clear coating.  Dag-nabbit!  If it's not one thing it's another when trying to get pretty finished enclosures!  LOL!

Govmnt_Lacky

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Re: Problem with powder clear over decal...
« Reply #3 on: February 25, 2015, 04:45:21 PM »
Long shot but....

Is there any chance to lacquer the decal BEFORE applying to the enclosure and powder clear? Or will the powder process not jive with the lacquer?

wgc

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Re: Problem with powder clear over decal...
« Reply #4 on: February 25, 2015, 07:59:48 PM »
Papilio white bake-on laser decal paper...  with a color laser printer.

Guys over on a powdercoat forum say it's because the dormant colors pull through when clear coating.  Dag-nabbit!  If it's not one thing it's another when trying to get pretty finished enclosures!  LOL!

Actually I think the ink on your decal diffused a bit into the clear while it was curing. It gets less opaque as a result. The dormant won't travel through the decal after its cured.  You might try doing a white top and red dormant sides, decal, then clear.

Edit:  As I think about it a white top won't help you much if the ink is diffusing. A fixative spray after printing it might help that but no way to know without trying.

At any rate, it's a cool decal and your powder coat looks good too.
« Last Edit: February 25, 2015, 08:46:42 PM by wgc »
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Justus

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Re: Problem with powder clear over decal...
« Reply #5 on: February 26, 2015, 11:13:34 AM »
I don't think it's the ink diffusing.  This is laser paper with color laser printing.  My second pic is blurry but it really looks like what the powder guys are saying...  the dormant bled into the clear.  They say that's supposed to happen with dormant colors, and there's no way to lock in the color.  You can't even shoot black over a dormant color without some bleeding.

Seeing as how I ordered about 6 or 7 colors of powder to start, all of them being dormant, my only hope is that a full cure on the first coat of clear will lock in the dormant color.  Otherwise, I'm going to have to decal and then use spray clear lacquer or something, which is not what I wanted to do.  Only other option is to order new colors that aren't dormant.

Govmnt_Lacky

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Re: Problem with powder clear over decal...
« Reply #6 on: February 26, 2015, 11:49:06 AM »
What about color... then light clear... then decal... then more clear? Or, am I understanding this wrong?  :-\

Is the decal color bleeding through to the clear OR is the initial powder color bleeding through the decal?

Justus

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Re: Problem with powder clear over decal...
« Reply #7 on: February 26, 2015, 01:32:41 PM »
Initial powder color bleeds into the clear.  Apparently that's how "dormant" colors work. 

The process of color, then clear (fully cured), then decal, then clear again is what I'm hoping will work.  I've been told that it shouldn't work that way because the color will still bleed into the 2nd coat of clear...  but I can't lose much by giving it a shot.

wgc

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Re: Problem with powder clear over decal...
« Reply #8 on: February 28, 2015, 09:24:48 PM »
I think you're referring to "cross linking".

However, if you cured the base coat, there should be no bleed into clear, since polyester powder is most often thermoset. I believe most toner is thermoplastic, which is why you can do toner transfers.

Further, the decal should be a bit of a barrier to any base coat bleed if there was any, especially since its white. 

Afik, dormants work as a result of a multi sided crystalline particle, much like flip flop colors do. The clear just changes the angle of refraction, so you get an iridescent effect based on angle light hits the particle. Not bleed. That said, some people will half cure the base coat of any two coat process in an effort to promote a better bond between coats, aka cross linking.

If you want to narrow it down, put some base coat on a scrap, and cure it. Do the same with some toner. Then sprinkle enough clear to over cover on each and bake. You'll have your answer, though a solution may take a bit more work.

No offense to the powder forums but there's lots of well intentioned but bad info out there. Take it all with a grain of salt unless it's direct from the powder manufacturer.

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Justus

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Re: Problem with powder clear over decal...
« Reply #9 on: February 28, 2015, 11:03:23 PM »
I think you're referring to "cross linking".

However, if you cured the base coat, there should be no bleed into clear, since polyester powder is most often thermoset. I believe most toner is thermoplastic, which is why you can do toner transfers.

Further, the decal should be a bit of a barrier to any base coat bleed if there was any, especially since its white. 

Afik, dormants work as a result of a multi sided crystalline particle, much like flip flop colors do. The clear just changes the angle of refraction, so you get an iridescent effect based on angle light hits the particle. Not bleed. That said, some people will half cure the base coat of any two coat process in an effort to promote a better bond between coats, aka cross linking.

If you want to narrow it down, put some base coat on a scrap, and cure it. Do the same with some toner. Then sprinkle enough clear to over cover on each and bake. You'll have your answer, though a solution may take a bit more work.

No offense to the powder forums but there's lots of well intentioned but bad info out there. Take it all with a grain of salt unless it's direct from the powder manufacturer.

This is good to know, because I think I *did* undercure my base coat originally.  So by shooting clear and doing a full cure, that should, in theory, stop any additional bleeding (cross-linking) with a second round of clear over a decal.

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Re: Problem with powder clear over decal...
« Reply #10 on: March 01, 2015, 10:52:26 AM »
Red in notorious for bleeding through . . . even dormant red.  I've tried doing white graphics over dormant red, then sprayed a clear powder over the finished box . . . result was pink graphics.  I've tried dormant red, then full cure clear, then white graphics . . . then a second coat of clear over the graphic.  That should have worked, right?  Wrong -- still pink graphics.

As basically described above, best bet would be to shoot the dormant red, cure, cool to room temp, shoot the clear, full cure, cool . . . then apply your decal.  You may want to then try a lower temp clear to seal the decal on top and bake the box for the minimum amount of time necessary to cure the low-temp clear.  Keep tabs on your oven temp, too.
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