Fixing a finish

There are few things more frustrating than arriving at the end of a long term modeling project only to have an issue arise with the finish coat. That’s my opinion at least.

After spraying Model Master acryl flat clear (4636) onto these two Pere Marquette automobile boxcars, a patchy haze appeared around the decal areas. I’ve been using this product for a few years and have never seen this before.

I sent photos to a few modeling mentors for suggestions. They were all surprised with the issue. This haze wasn’t under the decal but around the perimeter.

I had used Micro Sol as a final decal setting solution. It’s more potent than Micro Set and I wanted the decals to snuggle down. I waited a few days before shooting a gloss coat on the models. There wasn’t any hazing after that coat dried. The flat coat was applied a couple days later and the hazing showed up the following day.

The lead image and the one above documents the situation on the two models. I set the models aside and focused on another project. Recently I decided it was time to step up and fix the finish. Here are the methods I used to remove the haze.

  • The first attempt used a cotton swab soaked in distilled water and scrubbed onto the offending areas. This was recommended by a couple friends. I tried this several times without a change in the haze.
  • In round two, I dampened a cotton swab in 91% isopropyl alcohol and scrubbed the offending areas. I tried this a couple of times without a change in the haze. I was very careful with the alcohol as I did not want to remove the paint.
  • Moving along, I applied a diluted flat coat with a brush. I used Testors Aztek Universal Acrylic Thinner with the Model Master acryl flat clear. A couple drops of each were applied to a styrene square and mixed together. This was applied to the hazy areas. Some of the lighter haze disappeared but the heavier areas did not seem to change.
  • Next, I applied straight Testors Aztek Universal Acrylic Thinner to the hazy areas. Again, some of the lighter haze disappeared but the heavier areas did not seem to change.

In between these steps, I applied decals to another model. As I finished those tasks, I wondered what would happen if I used the Micro Set on the hazy areas. I used a brush to apply the Micro Set on the hazy areas. When that dried, I was pleasantly surprised to find all but the heaviest of the haze was gone from the models. I applied more to those stubborn areas and noticed additional improvement.

As you can see, the haze has mostly disappeared. Some remnants in the steel bracing corners can be seen, but I think that can be eliminated using a pin wash of a darker tone. A little bit remains around the AND on the right side. I’ve done the Micro Set dance a few times on that area and this seems to be the best it will be.

Here’s a look at one side of the other car. At this point, I’m ready to move forward and wrap these up. These are modified Speedwitch Media HO scale resin freight car kits with custom decal sets for the 1926 as-built lettering.

A light application of PanPastel weathering followed by color pencil highlights and chalk marks are the next steps, then small paper squares will be glued onto the models for route cards. I am relieved that the Micro Set decal solution eliminated most of the hazy areas on these models.


Special thanks to Lester Breuer, Nelson Moyer, Bruce Smith, and George Toman for their suggestions on improving the finish on these models.

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3 thoughts on “Fixing a finish”

  1. Thank you for the SP auto box decal source. I am building a Northeastern kit that I bought at a train show and the box was missing the decals.

  2. Hi Eric, Thanks for sharing your issue and how you used the scientific method to find a solution. After fifty years of reading about model railroading something sticks in the back of my mind about recommendations to rinse, wipe or somehow clean off the decal glue and setting solution residue before moving on to the weathering/finishing steps. I have not done this unless I noticed some residue but after your experience it seems that, once decals are snuggled and dry, of course, this is an easy precaution to avoid oversprays reacting with leftover chemicals, especially lacquer/solvent-based coverings over sometimes multiple kinds of water-based remnants. Thanks so much. Model on! Owen

  3. Very frustrating to have happen. I think it was the result of a high humidity blushing effect.

    Was there a large temperature and/or humidity change between the gloss and flat coats?

    On furniture they recommend getting the humidity way down and respraying, but if the straight acrylic thinner application didn’t do the trick, I don’t think respraying would have.
    Only other things I would try:
    Champ decal set (I have a little left that I decanted to a glass bottle so it wouldn’t cease to exist.)
    Vinegar

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