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Trashed paint job

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  • Member since
    August 2020
  • From: Fort Worth, Texas
Trashed paint job
Posted by Deaf Smith on Monday, January 11, 2021 7:11 PM

What a mess. This is a 1/48 Hasegawa F-4 kit.  I brush washed the entire model pre-assembly with soapy water.  After assembly I wiped the model with alcohol before priming with Alclad lacquer primer. Two coats of primer followed a couple days later by two coats of AK acrylic followed a week later by two coats of Testors lacquer gloss coat. After three more days I went to mask for final detail painting and when removing Tamiya masking tape to reposition it I pulled up everything down to the plastic.  Are you kidding me?

I tested several more places on the model.  Same story. What in the world?  As I had nothing to lose at this point I took to using Scotch blue to remove all the paint I could. I got over 95% off lifting with burnished tape. The only places the primer and paint held is on areas where I had worked filling and sanding thoroughly. It has been suggested to me that the model was burdened with mold release contamination which is the only thing that makes sense to me at this point.

I have NEVER experienced anything like this.  Can I save this build?  Is there a solvent that I can use to clean up the remaing small amounts of primer and paint in joints and seams or am I left to seeing if I can clean it up sanding?  

Deaf Smith

  • Member since
    April 2020
Posted by Eaglecash867 on Monday, January 11, 2021 7:33 PM

Sorry to read about that happening to you.  What strength is the alcohol you wiped with and what type?  Isopropyl or denatured?  I started off using 91% isopropyl alcohol to strip paint safely without damaging or altering the chemical composition of the plastic.  These days I'm using 99% aviation grade isopropyl alcohol to remove paint and primer safely.  It takes a little soaking and gentle scrubbing with a cheap electric toothbrush, but that has worked for removing every kind of paint I have used on models.  It'll strip it down to the bare plastic with none of the chemical side effects that using certain other things to strip paint can have.

It does sound like a mold release agent problem, and I guess your pre-wash/wipe didn't remove it.  My go-to for an initial bath before painting is a bath in Simple Green, followed by a rinse under hot water, followed by an isopropyl alcohol dunk.  After the parts are dry, I shoot decanted Tamiya Grey Primer thinned with MEK.  The MEK makes the primer grab onto the plastic like grim death, and every paint I have tried has adhered well to the Tamiya Grey Primer.  Haven't tried Alclad lacquer primer, so maybe someone who has can tell you more about that.

Even with as well as the Tamiya primer grabs onto the plastic, it can still be removed using the isopropyl alcohol/electric toothbrush method.  It just won't mechanically pull off the plastic.

"You can have my illegal fireworks when you pry them from my cold, dead fingers...which are...over there somewhere."

  • Member since
    August 2014
  • From: Willamette Valley, Oregon
Posted by goldhammer on Monday, January 11, 2021 8:38 PM

Prior to priming, I give the whole thing a good scuff with a grey scotchbrite pad until all the shine is gone.  Won't damage details like sanding can.

You can get at auto parts or auto paint store.

  • Member since
    March 2003
  • From: Western North Carolina
Posted by Tojo72 on Tuesday, January 12, 2021 9:17 AM

I doubt its mold release,most kits aren't greasy with mold release. I have built numerous Hasegawa Phantoms without problems.I can't say,but its gotta be something else in the process,I never washed a kit in my life and haven't had problems.I will say that I remove a lot of the tack from tape by sticking it to a clean metal surface like my fridge to remove some stickiness

  • Member since
    November 2018
Posted by oldermodelguy on Tuesday, January 12, 2021 9:35 AM

Well this will sound strange, doesn't matter since it is my experience. I stopped using alcohol as my final wipe down solvent because I saw strange looking motor oil in water swirls in my primer. Seemed to work ok other than uneven drying times and that look. I was blaming substances in the primer. Nope, changed back to odorless mineral spirits and never seen it since. Maybe it was just the brand of alcohol I was using but I'm sticking with MS.

  • Member since
    March 2015
  • From: Close to Chicago
Posted by JohnnyK on Tuesday, January 12, 2021 11:33 AM

I use Simple Green to wash my models prior to painting. I also "de-tack" my tamiya masking tape by sticking to my forehead.

  • Member since
    August 2020
  • From: Fort Worth, Texas
Posted by Deaf Smith on Tuesday, January 12, 2021 1:20 PM

Many thanks Eaglecash and everyone!  So grateful for all of your observations and suggestions.  Some great tips here which I intend to employ in the future.

FYI before priming I wiped the model down with I think a mix of denatured alcohol and water. I also detack my tape before masking.  

With 99% IPA and my wife's (JK :) electric toothbrush I have happily removed all paint and primer and am down to clean plastic.  I will wash with Simple Green and give it a scruff up with the gray scotchbright that goldhammer suggests.

I think I'm going to use a different primer also.

Thanks again to all!

Now to Amazon to order me a new toothbrus...

Deaf Smith

  • Member since
    April 2020
Posted by Eaglecash867 on Tuesday, January 12, 2021 1:36 PM

Be careful about using denatured alcohol, especially for doing your pre-primer surface prep.  They put all kinds of random things, including MEK, and sometimes oily substances in it to make it taste bad so people don't drink it.  One batch of denatured alcohol may work fine, and then the next batch from the same manufacturer doesn't.  Some batches may even start melting the plastic.  They're pretty liberal with what they put in the stuff to keep it "safe".

"You can have my illegal fireworks when you pry them from my cold, dead fingers...which are...over there somewhere."

  • Member since
    August 2020
  • From: Fort Worth, Texas
Posted by Deaf Smith on Wednesday, January 13, 2021 9:15 AM

Thank again, Eaglecash.  Gonna lose the denatured alcohol.  

Deaf Smith

  • Member since
    November 2008
  • From: Central Florida
Posted by plasticjunkie on Thursday, January 14, 2021 6:26 AM

Tojo72

I doubt its mold release,most kits aren't greasy with mold release. I have built numerous Hasegawa Phantoms without problems.I can't say,but its gotta be something else in the process,I never washed a kit in my life and haven't had problems.I will say that I remove a lot of the tack from tape by sticking it to a clean metal surface like my fridge to remove some stickiness

 

Ditto

The only time I wash parts is when they are resin, otherwise I don’t wipe or clean anything and have never had an issue. I have built a bunch of Hasegawa Phantoms and Tomcats and never cleaned them prior to painting.

The only time paint pulled up while removing tape was when I Used Acryl Primer that I later found out it’s notorious for doing just that. Like Tojo said, something went wrong with the cleaning process. I suspect cross contamination from one of the cleaning agents used.

 GIFMaker.org_jy_Ayj_O

 

 

Too many models to build, not enough time in a lifetime!!

  • Member since
    August 2020
  • From: Fort Worth, Texas
Posted by Deaf Smith on Thursday, January 14, 2021 9:12 AM

Thank you.  By a acryl primer do you mean any acrylic primer or are you referring to a specific primer? What primer do you use?  

Deaf Smith

  • Member since
    June 2014
Posted by BrandonK on Thursday, January 14, 2021 9:46 AM

Other than something on the plastic that caused this, it is most likely a primer issue. As this is the one that you are betting to hold to the surface and it did not. Use Tamiya white or grey primer and you will never have an issue with lifting.

BK

On the bench: Alot !

On Deck: Alot more !

 

  • Member since
    May 2013
  • From: Indiana, USA
Posted by Greg on Thursday, January 14, 2021 10:41 AM

Sorry this happened and glad you got it all stripped down.

Deaf Smith
.......priming with Alclad lacquer primer

Can you elaborate? The only Alclad primer I've ever used is ALC306 White Primer and Micofiller. Is this the stuff you used?

I'm just curious as I've found the stuff to be pretty much bulletproof.

-Greg

  • Member since
    August 2020
  • From: Fort Worth, Texas
Posted by Deaf Smith on Thursday, January 14, 2021 11:07 AM

Thank you, Greg.  Yes, that is the Alclad I used.  I added some black to the gray to darken it up as the gray was barely distinguishable on this model.  I am wondering if I had used this one particular alcohol and water mix I have to prep the model, and I'm wondering(as I cannot remember) if the alcohol in that mix is denatured in which case perhaps I contaminated the surface with the chemicals in the denatured alcohol.  Possible? 

Deaf Smith

  • Member since
    November 2008
  • From: Central Florida
Posted by plasticjunkie on Thursday, January 14, 2021 11:33 AM

Deaf Smith

Thank you.  By a acryl primer do you mean any acrylic primer or are you referring to a specific primer? What primer do you use?  

 

Model Master Acryl, in my book pure junk. 
I use lots of Alclad metallic paints but I'm not too fond of their primers. I get better results using Tamiya primers.

 GIFMaker.org_jy_Ayj_O

 

 

Too many models to build, not enough time in a lifetime!!

  • Member since
    April 2020
Posted by Eaglecash867 on Thursday, January 14, 2021 12:56 PM

Deaf Smith

 I am wondering if I had used this one particular alcohol and water mix I have to prep the model, and I'm wondering(as I cannot remember) if the alcohol in that mix is denatured in which case perhaps I contaminated the surface with the chemicals in the denatured alcohol.  Possible? 

 

 
If you used denatured alcohol in the mix, that might be what caused it.  Another possibility is that the soap you had used before that might not have been completely rinsed off before you used the alcohol/water mix.  I just remembered a time when I took a part out of the Simple Green bath and then put it straight into the isopropyl alcohol without the water rinse first.  I couldn't see it, but I could feel this strange texture on the plastic so I put it under a magnifier.  The alcohol and simple green had reacted and formed a translucent green film on the plastic.  I ended up just repeating the washing process, this time remembering to thoroughly rinse with hot water before it went into the alcohol.  After that, the strange film was gone.

"You can have my illegal fireworks when you pry them from my cold, dead fingers...which are...over there somewhere."

  • Member since
    August 2020
  • From: Fort Worth, Texas
Posted by Deaf Smith on Thursday, January 14, 2021 1:15 PM

Thank you, once again for your observations.  Hopefully I am good to go now as once I had the model stripped with 99% IPA I washed with Green Power.  As this did not remove residue left from the stripping I then wiped down with 99%.  Still streaky so I wiped down with IPA and water mix and then scrubbed with Dawn and rinsed.  Let dry and scuffed with Scotchbrite gray fine pad and cleaned up with alcohol and water mix.  Then one more good Dawn scrubbing and a thorough rinsing and one more Scotchbrite skuff and wiped down with a water wetted cloth.  

If the lacquer doesn't adhere to this I'm pulling the .45 Long Colt from the safe and sending the model to see Jesus.  

Deaf Smith

  • Member since
    May 2013
  • From: Indiana, USA
Posted by Greg on Thursday, January 14, 2021 1:30 PM

Deaf Smith
Thank you, Greg. Yes, that is the Alclad I used.

You're welcome. And I'm baffled.

Please do let us know what happens on go #2.

-Greg

  • Member since
    August 2020
  • From: Fort Worth, Texas
Posted by Deaf Smith on Thursday, January 14, 2021 1:33 PM

Will do.  So grateful for this community and the interest it's members demonstrate in helping one another.  

Deaf Smith

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