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opus999

Decals turning black after 6 months!

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Long time reader... first time poster... 

 

HELP!!! Has anyone had this happen before? I finished a Testors 1/72 B-66 Destroyer on August 30th last year, and about a month ago I noticed the decals were turning black! Since then, I've seen it get progressively worse. I don't harbor any hope of salvaging the model, I just don't want to have it happen again.  There were a few "firsts" for me on this build, so there are a lot of variables.  But, here is the sequence  of paint and decals:

  1. Tamiya spray gloss black (base)
  2. Alclad Polished aluminum + Alclad aluminum
  3. Alclad Aqua Gloss clear
  4. Decals (original kit decals purchased on e-bay)
  5. Testors metalizer sealer (pretty old bottle)

 

Here is a photo of the decals under the cockpit on the day I finished it:

64c5btO.jpg

 

Here is a photo taken tonight of the same decals:

 

HVdWQ4x.jpg

 

Here are a couple more examples of the decals that have turned black

 

2WfnigJ.jpg

 

vleRD0j.jpg

 

I've had decals turn brown before, but only after a couple of decades.  But this has only been 6 months! The decals I bought were original, so they were 20 -25 years old, but in great condition (not yellow). I want to blame the decals, but I wonder if there was some reaction between the aqua gloss and the testors sealer that affected the decals sandwiched between?

 

I'm just hoping to prevent this in the future, so I thought I'd throw it out to the community to see if anyone had any insight.

 

Not to sound too melodramatic, but this is really heartbreaking; there is a long story behind this model, but in short it was the model I've been wanting to make since 1989 and I did it!  Then this happened...:swear:  Any help or insight would be appreciated -- I don't want to go through this again!

 

For what it's worth, here's what it looked like in it's prime (5 months ago! Ha Ha!):

q0A3XP1.jpg

 

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Since this only happens around the decals I think it is safe to ignore the paints and protective layers themselves. Have you been using any kind of decal softener/setter that might have left residues below the decal that react with the clear coat? Is this also happening in areas NOT painted with Alclad?

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Hmmm, that's an odd one.

It looks like the Alclad has reacted with the top coats above it.

As armored76 pointed out, maybe it was brought on by the decal solution affected by the 

Testors metalizer sealer?

Were the decals well and truly dry, and the model washed of decal solution, before the Testors metalizer sealer was sprayed on?

Rick.

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Posted (edited)

Thanks for the feedback! When I wrote the original post I was racking my brain to remember if I used solvent or not. I generally try to avoid it on my alclad builds. I know for certain that I used a *lot* of it on the national insignia on the sides (there are some indentations in the fuselage that I haven't been able to determine the purpose of) but I don't remember using any solvent at all on the top.

 

I suppose I might  have put a little on, but I just don't remember doing it -- like I said, I try to avoid it.

 

It may not look like it, but the entire aircraft is painted with alclad (looks much better in real life :P ), and this was the first time I've used a Aqua Gloss / decal / Sealer combination. In the past its been Aqua gloss / decal /aqua gloss  for glossy aircraft and Aqua gloss / decal / Testors Acryl flat for flat aircraft.  I've used plenty of solvent on the non-alclad builds. In the 3 years since I came back to the hobby I haven't had any problems with these combinations, but they're all acrylic based.

 

The last couple builds have been Aqua gloss / decal /Decanted Dullcote (because I'm not thrilled with the acryl flat), but  it's only been a couple of months for those.

 

Oh yeah... the build I did after the B-66 was an Alclad coated F-86, but I was going for an "Airshow" look and used Aqua gloss / decal / aqua glass, and had to use a fair amount of solvent on a couple of decals.  No problems with that one yet, but it's only been 4 months.

 

The decals had been dry several days; I had washed the surface before applying the sealer.

 

I had thought that it looked like the Alclad had reacted as well, but I just don't understand Acrylic paint well enough: Is acrylic paint porous enough when dry to allow such reactions to happen? If so, maybe I should stop using the decal solvent altogether on the alclad builds?

 

This really is a weird issue -- I've built models since I was 9 and never had anything like this happen.  However, I really only started using alclad and a gloss coat base for decals 3 years ago when I came back to the hobby (both of which I learned about on britmodeller!). I hope this is just a one-off problem with old decals. :rage:

Edited by opus999
added a period.

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I just remembered something that may be the key... The undercoat of the alclad was tamiya gloss black in a rattle-can. The finish came out slightly dimpled so I decided to try and fix it. Several modelers on line said they used polishing powders and a couple said they used brasso with very good results. I thought that was a bit odd because I would imagine brasso would be acidic, but I figured if I washed the model well enough (and 2 different people said they had good results...) then it might be OK.

 

Maybe not.

 

I thought I'd washed the model well enough, but maybe I didn't. A reaction between Alclad with any residual brasso would seem to explain the black coloring -- since that's the color of the base coat. I'm not sure why it's only under the decals though.  Unless the rest of the paint is doomed to turn black and it's just starting under the decals. Arrrgh.  I wish I hadn't tried that on a model that was so important to me. :(

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The mystery deepens...  First off, as predicted the B-66 looks like total garbage now:

sjjzCwY.jpg

GCWuV8d.jpg

 

Notice in the picture on top, that the panel behind the "rescue" arrow is unaffected, but the yellow square to the left of the arrow and the stencil below are already black.  The panel behind the arrow was painted first with Alclad polished aluminum, and then lightly dusted with Alclad aluminum. The parts that have turned completely black are just straight polished aluminum.

 

Same with the tail fin: The panel behind the words "U.S. Air" is just straight polished aluminum, while the panel behind the word "Force" is polished aluminum with a dusting of aluminum.

 

Now the really alarming part: Tonight I found another recently built model exhibiting the same issue. The propellers on my B-10B (completed 10/05/2017 - 2 months after the B-66) were painted (from base to surface): Tamiya Gloss Black Spray > Alclad polished aluminum > Alclad Aqua Gloss (I can't remember for sure, though) > Decal > Alclad Aqua Gloss. I found that they too have black spots forming under the decals.

yNeVf9a.jpg

Oh1Cyvd.jpg

For comparison, here's how it looked when I finished it:

CwKp9pz.jpg

 

I didn't do anything funny with the preparation, so my hypothesis about using chemicals to polish the B-66 seems to be out the window.

 

Alarmed, I got my F-86 (mentioned in a previous post) that I finished November 12, 2017 out of the cabinet and examined it closely under a magnifying glass and didn't see anything alarming (knock on wood). It too was painted: Tamiya Gloss Black Spray > Alclad polished aluminum > Alclad Aqua Gloss > Decal > Alclad Aqua Gloss.

 

So.... I don't know what I'm looking for here. I'm not sure anyone can help me, I guess I just want to know if I'm the only person in the world who has had this problem! Now I'm in the middle of two Natural Metal Finish air craft ( CF-104 and F-84G ) and I'm afraid that they'll look like trash in a year.  And I've tried to do everything right.

 

Frankly, I'm so upset I'm seriously considering leaving the hobby.

 

Any insight would be helpful... but I may just be unique.

 

Edited by opus999

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Yeah, it kind of does! But, not so much under a magnifying glass. I have confirmed it is under the decal. and has been slowly "growing".

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My only, probably useless thought would be: perhaps the primer coat didn't have long enough to cure before the application of the Alclad? Alternately, what decal setting solution, if any, did you use?

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2 minutes ago, Procopius said:

My only, probably useless thought would be: perhaps the primer coat didn't have long enough to cure before the application of the Alclad? Alternately, what decal setting solution, if any, did you use?

Well, I waited 24 hours with the primer, since it was a lacquer. I suppose it wouldn't hurt to wait, say a week, and see if that helps. Trouble is, I won't know for a year if it helps or not!

 

I didn't use any decal setting solution on the propellers. On the B-66 I only used setting solution on the stars and bars on the side of the aircraft; the rest I didn't use any.

 

Weird, huh?

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Just now, opus999 said:

Weird, huh?

Bizarre, man. 

 

The blackening (for lack of a better, more technical term) doesn't seem anywhere near as pronounced on the B-10 (which looks cool as heck, by the way) -- it almost looks more like some chipped paint in the photo, anyway. Maybe this is still a one-off? I've never had Alclad do this to me (though it's misbehaved in other exciting ways), and I'm baffled. Washington's infamous humidity? Daemonic possession? 

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7 minutes ago, Procopius said:

Bizarre, man. 

 

The blackening (for lack of a better, more technical term) doesn't seem anywhere near as pronounced on the B-10 (which looks cool as heck, by the way) -- it almost looks more like some chipped paint in the photo, anyway. Maybe this is still a one-off? I've never had Alclad do this to me (though it's misbehaved in other exciting ways), and I'm baffled. Washington's infamous humidity? Daemonic possession? 

I'll go with the possession. Where I live in Washington is a desert -- we only get 3 inches of rain here a year.  Otherwise I'd agree with the humidity theory. :D

 

Thanks for the comment on the B-10.  I should put it in ready for inspection.  I am quite proud of it, especially since it was a total and complete pain to build.

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Don’t know if this will help but I have had two similar experiences. First, the old Scalemaster decals supplied with most Testors reboxings would turn a blotchy brown under the decals when exposed to light, after a fairly short period of time. The problem seems to have been with the glue which turned a gluey white when wetted. Dried clear but came back as brown. When I say old, I mean manufactured years ago, not chronologically old. They were as described when brand new. Later, Scalemaster began labeling their decals as “invisi-clear”. I suspect that they recognized the problem and fixed it.

Second, I found to my great regret that that Tamiya Semi-gloss rattle can spray seems to dissolve their metallic rattle can metallic (TS-84). I found this out at the very last step of a NMF B-57. Application of the semi-gloss turned the mettalic Black. Actually I think it revealed the gloss black under coat which is why I used them term dissolved. Interestingly I had used a brush applied coat of Future over the TS-84 to ensure no slivering. The Future was apparently uneven in thickness because it’s brushstrokes we’re apparrent in the blackness. A thicker coat of Future probably would have prevented the reaction.

 

Whew! That should have been more than one paragraph.

 

What I think I know from all that is that metallic finishes can be dissolved revealing that black under coat beneath when certain chemicals are applied over them and that older Scalemaster decals had something pretty suspect in their glue.

 

i’d blame the Scalemaster and avoid them in the future. Too bad since they were very nice otherwise.

 

 

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So, the only thing this reminds me of is that certain types of permanent marker applied under paint, such as to preshade panel lines, will eventually bleed through the overlying paint. This looks like the Tamiya Gloss Black basecoat doing the same thing. I've always used Alclad's own gloss black basecoat so I wonder if there is some chemical incompatibility between the Tamiya paint and the Alclad, although the decals, probably through the adhesive, are obviously involved too since the discoloration only occurs there. It could also be a chemical reaction between the decal adhesive and the underlying Alclad layer. 

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It looks like the decal softner has attacked the Aqua gloss, and then the underlying Alclad, Alclad is pretty delicate stuff at the best of times It's probably happening on the the coloured part of the decals but just not showing as bad.It seems to be showing worse on the clear part of the decals

I have had Micro sol soften Aqua gloss, so tend to use Tamiya X-22 gloss before and after decals now, then leave if a gloss finish is required or matt with Winsor & Newton Galeria varnish

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@Trenton guy: Great thinking! I didn't consider the glue on the decal. I remember vividly in the 80's the milky white junk on the decals from Testor's models and (not knowing much about decals) trying to decide whether to wash it all off or keep it on.  I have so many Testors builds from the 80's and 90's with brown splotches on the decals from that stuff.  Looks terrible on my white/gunship gray SBD!

 

This seems like a likely culprit. However, the B-10 decals were by someone else (although, the principle could be the same).  If decal glue is the culprit, I wonder how I could make another B-66 (since I want to re do this one so badly now!)? I've never messed with do-it-yourself decals and I've found there are practically no after-market B-66 decals. :( I couldn't even find generic USAF lettering!

 

@VMA131Marine: I had feared the same thing (that the Tamiya was soaking through), but I used the same base coat on my F-86 that I did about the same time, and (knock on wood) haven't had any evidence of the same thing happening.

 

@colin: Decal softener is one of my other ideas, too. I'm not sure how porous the Aqua Gloss is, so this seems like a likely theory too. Although, the F-86 I mention above, had the same paints and I used solvent with no ill-effects ( so far... ). I hope that It's not a problem with the softener and Aqua Gloss because I used it on my recently completed CF-104 -- Although, the decals sat for 6 months with no overcoat, so maybe the softener could evaporate ???? With the X-22 gloss, do you spray or brush paint?  I have never had a good finish spraying and like the Aqua Gloss because I can paint it with a hand brush and have a perfect finish.

 

Thanks for all the feed back guys! I truly appreciate it, and it gives me more to think about than before.  I just wish I didn't have to wait 6 months or more to see the results!

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I spray the X-22 thinned with Mr Levelling thinner 50/50 light coat first then build up, same for the final coat over the decals, light coats then build up, I do this even if I'm putting a matt finish on last to seal the decals.

Just leave to dry for a few days to make sure the clear has dried really well before decals go on.

Seems to work for me so I now only use that method

 

I4rAVSg.jpg

 

KCViWIH.jpg

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On 10/1/2018 at 2:23 AM, colin said:

 

I spray the X-22 thinned with Mr Levelling thinner 50/50 light coat first then build up, same for the final coat over the decals, light coats then build up, I do this even if I'm putting a matt finish on last to seal the decals.

Just leave to dry for a few days to make sure the clear has dried really well before decals go on.

Seems to work for me so I now only use that method

Hmm. OK, I guess I will need to try that. In the past, I don't think I used Mr. levelling thinner.  I've discovered it since and use it all the time, so maybe it's time to go back to trying the X-22.

 

Beautiful NMF examples, by the way! What did you use?

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I've devised a test -- I'm going to take some scrap plastic, apply alclad using my usual method and then take examples of the decals from all of my previous builds (and a few upcoming ones) and apply them.  Then, I'll wait and see if any turn black.  By doing this, I hope to determine whether it is a decal issue or not. Of course, it will take about 6 months to see results, but at least I might get an answer...

 

I will post pictures when I get around to doing this.

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9 hours ago, opus999 said:

 

 

Beautiful NMF examples, by the way! What did you use? 

I prime the model with Tamiya AS-12 decanted for airbrush use, then a combination of Gunze supermatallics and Alclads. I don't use any other primer under the AS-12 as it can be sanded and re-applied if you find any defects and dries to a hard finish which takes the other metallics well

Can't take the credit for this idea as I copied this

https://www.youtube.com/watch?v=bM_SUXDTQag

 

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12 hours ago, colin said:

 

I prime the model with Tamiya AS-12 decanted for airbrush use, then a combination of Gunze supermatallics and Alclads. I don't use any other primer under the AS-12 as it can be sanded and re-applied if you find any defects and dries to a hard finish which takes the other metallics well

Can't take the credit for this idea as I copied this

https://www.youtube.com/watch?v=bM_SUXDTQag

Ha ha!!! I was encouraged to try AS-12 in the last couple of weeks by watching the same video! In fact, I'm shooting some test pieces with it for my MiG-15 build.

 

So, with the Gunze and Alclads, do you dust it onto the AS-12 so that it still shows through, or do you coat the AS-12 completely with them?

 

With Alclads, I use the "dusting" method. I've found that I can never get Alclad aluminum to look realistic -- it just looks like silver paint to me. However, if I put on a coat of Alclad polished aluminum, and then dust it with the Alclad regular aluminum to tone down the shine, it looks very realistic to me. I think that method emulates how a polished surface would eventually get dull through corrosion. Given the troubles I've had with the polished aluminum lately, I'm trying to find alternatives.

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I tend to lightly mist a coat of Gunze superfine silver or stainless depending on how bright I want it to look, I don't try to get a true polished (chrome)look, but post war jets tended to look more shiny, except when deployed to a war zone when there was less time to keep them clean.

I never use Alclad dull aluminium as it just looks way to grainy for my liking, I use airframe aluminium on small panels for varation, and their hot metals

To be honest the Tamiya AS-12 does a pretty good job on its own of looking like a nmf. It also sprays fantastic and dries very quick, it also covers small blemishes very good as you can go quite heavey when spraying as it shrinks back really nice over details

If you can get some Mr Levelling thinner and use that to thin the AS-12 and also after you have applied your others coats, go over the entire model with some neat Mr levelling thinner, that really brings them all together.

Try on a test model first though

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