Using Tamiya X-21 Flat Base to replicate faded paintwork on diesel locomotive

I recently came across a YouTube tutorial, which showed Tamiya X-21 Flat Base being used to replicate faded paintwork. I have just tried this method, but with less than convincing results. In the video, the product was thinned with isopropyl alcohol. This is something I do not have, so I simply applied the X-21 undiluted. As expected, the liquid dried to a chalky finish, but when I attempted to rub away the excess (as suggested), I was left with noticeable brush strokes. Perhaps the fault was mine for not diluting the product. Would it have been better to mix it with water (in the absence of isopropyl alcohol)?
I would be interested to hear from anyone who has had success with the method. I do not own an airbrush, so brush painting is my only option.



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Hi Paul,

Tamiya paints are terrible to brush! I suspect your vid showed it thinned with alcohol and then sprayed, right? Flat Base is meant to be added to other Tamiya gloss paints to make them flat, not used on its own. And diluting with water will still get you in a mess - Tamiya acrylics are not truly water-based but use a thinner that smells suspiciously like ethylene glycol (antifreeze) and will strip off underlying paint when brushed on. Can you post a link to the tutorial?


Thanks for your response.
Unfortunately, copying the link didn’t seem to work.
However, you can view the video by entering
‘The Weathered Locomotive: Easy Pro Paint Fade Tip - Boomer Dioramas’.
As you will see, the Flat Base was simply applied by brush.

Any comments?


’The Weathered Locomotive: Easy Pro Paint Fade Tip’



Well that’s a new one on me! I’d be careful to test it on a junker first. The alcohol thins the paint, and I suspect it causes it to whiten - this was always a problem with the old Testors Dullcoat, which frosted if you accidentally hit it with alcohol spray (such as when misting track to ballast it, with a painted car nearby). Your local pharmacy should be able to supply the isopropyl alcohol…

I Went through the video. The alcohol would thin it and let it dry faster. I think that you just need to scrub a little more. He was using a dry brush and it was probably a little stiff.
I am going to try this first thing in the morning and try your way band the video. I will share my results.


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What about just doing a fade with your airbrush and paint.

I got it to work!!! I had to use rubbing alcohol (isopropyl 91%). I let it dry an took a stiff brush and it slowly came off. I had to work the brush marks down but they went away. I even used my finger to rub it off further. It is a chalky white filter in the end.
It did not work when I used water to thin it down. It would not scrub off. But I got it all off with the alcohol and a qtip. Cleans right up no problem.

Be aware I tested this on a model that was years old with enamel paint as the base. I did not try it on dried acrylic. I think the alcohol will strip it. Even though it is dried. Maybe lightly rub it off with alcohol mixed with water.


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@BigTodd, welcome to RailRoad Modeling and Kitmaker network.

Glad you got it to work. Thanks for the report.

Thanks for sharing this weathering idea. Need to give this a try and add the technique to my modeling quiver!

Ah, what’s old is new again. Those 70’s era Model Railroader magazines had some of the best weathering tips. I still use them on armor even today.