First Look Review
Photoetch Burnishing
AK Interactive Brass Photoetch Burnishing Liquid
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by: Kimmo Happonen [ THUDIUS ]


No single element manages to run the gamut of emotions with modelers as does photoetch. It is either loved, hated or viewed as a necessary evil. It can provide levels of detail and frustration that other media can't. One of those frustrations is how well, or poorly, paint adheres. Especially with fine grills and mesh. There is simply nothing more annoying than having built, painted and weathered a lovely model and discovering tiny, very shiny, flecks where paint has failed to adhere to the photoetch. AK Interactive has a solution, literally. Brass Photoetch Burnishing is a liquid that will blacken brass and other metal alloys and theoretically, improve paint adhesion. So, does it actually work? Let''s find out.

The product

The product comes in a fairly sturdy 100 ml plastic bottle with various warning labels and a brief description on how to use it. Clean and soak the photoetch for 3-5 minutes (or longer), agitate, and that's about the extent of the instructions. AK's website is even less informative. Opening the bottle, you will notice the distinct odour of nothing. A pleasant surprise. Needless to say, do not drink this stuff or splash any about. Clean up any spills or splashes immediately to prevent staining, and thoroughly wash your hands after use. Fully armed with the wealth of knowledge gleaned from the label, I decided to give it a try.


Since the product is in a plastic bottle, I figured a plastic takeaway container would do. I can happily report that the liquid did not damage the plastic, and that the previous contents were indeed, delicious. My chosen test subjects were scraps of photoetch frets and a leftover screen and strap from various manufacturers. I duly placed the pieces into the liquid, rocked the container a few times and waited the allotted 3-5 minutes, or the length of a Police track. I placed the pieces on a paper towel to absorb excess liquid and let them dry on the air. I used a set of stainless steel tweezers, no staining was evident, however, rinse your tweezers of choice afterwards to be on the safe side.

All the test pieces did indeed blacken quite nicely, and did so without any surface prep. And as you can see, the liquid remains quite clear after use which suggests that you may be able to reuse it, at least to some degree. I took a moistened cotton bud to one of them to see what would happen. To my surprise, the ”black” rubbed off, however, the brass definitely had the shine removed.

The next test was to dab a little liquid directly onto a fret. Again, it did blacken. And again, it swabbed off. So I repeated the test with a more generous application. This time the black remained, as did a slight ridge from the pooled liquid.

Next up, I burnished a few pieces with a toothpick. The black was removed as was the nickel plating on the Eduard fret. The brass underneath was nicely tarnished though where I hadn't used the point of the toothpick.

And lastly, I primed a few pieces with Vallejo Grey primer to test adhesion and whether the black would affect the paint. I primed several pieces, and a set of tread plate that was treated and not treated. On reflection, I should have tested with regular Vallejo paint as well because Vallejo primers tend to stick quite well as it is. I don't use enamels so you will have to perform your own tests to see if there is any improvement or not. Letting the primer dry for about 30 minutes, I scratched the surfaces with a toothpick. Not surprisingly, the primer started to come off both the untreated and treated surfaces. Leaving them to dry for a few hours produced more normal results. Vallejo primer needs to cure overnight to ensure good adhesion. I didn't notice any adverse effects to the paint.


Based on these initial tests, I would recommend this product as it does seem promising. Experimentation will be needed to determine how long to leave parts soaking to get the best level of darkening for different alloys. I suspect that the longer you leave the parts to dry, the less likely the black will rub off. The suggested retail price won't break the bank either, I paid a couple of Euros more for mine from an online shop, so do a little price comparison if that's a concern.
Highs: Odourless, not terribly expensive, appears to work equally well on different types of etch.
Lows: The black seems easy to remove.
Verdict: I would recommend this product as it does seem promising. Experimentation will be needed to determine how long to leave parts soaking to get the best level of darkening for different alloys.
  Scale: N/A
  Mfg. ID: AK 174
  Suggested Retail: 5.95 EUR
  PUBLISHED: Nov 16, 2014

About Kimmo Happonen (Thudius)

I got my first kit when I was about 7 or 8 and was immediately hooked. Magazines such as Fine Scale Modeler helped to push me to go beyond what kits had to offer before photo etch and resin were commonplace. I took a break of about 8 years and now I'm back at it making up for lost time. When I'm not...

Copyright ©2021 text by Kimmo Happonen [ THUDIUS ]. All rights reserved.


Thanks for getting this up. I'll try to remember to update as I get more familiar with how it works. Kimmo
NOV 21, 2014 - 04:03 AM
Thanks for the review Kimmo. I too have AK burnishing fluid in my stash and I too experimented a bit with it. It does seem to blacken PE but the burnish rubs off no matter how long I keep the photoetched parts in the liquid... the PE does seem to lose some of its sheen after the procedure, but it is still brass. Perhaps the PE is now more "prepped" for the paint to adhere? I have to admit I expected something like Blacken-it on the Friuls, but this is not what happens here. I would love to hear more thoughts about this product... Mario
NOV 21, 2014 - 02:11 PM
It does sound a bit strange that the blackening rubs off; the nature of the product makes it sound like that is what it is not meant to do. The stuff that you can buy in electronics shops for etching circuit boards will discolour brass: ferric chloride. It tends not to make a uniform colour, rather makes patchy browny colours partly depending on how long it is submerged, but it does dull it down and after washing, the remaining stain doesn't peel or rub off, you'd need to mechanically remove that layer and get down to fresh metal to lose the effect, I think. So what does Blacken It do to brass?
NOV 21, 2014 - 04:14 PM
Time will tell how this stuff really works, or doesn't. I don't have any Blacken-it so I can't say what it does to brass. I picked this up on the recommendation of another modeler who has been around the block a few times so I'll give the product the benefit of the doubt. One thing that might improve bite is to clean the etch as per the instructions on the bottle. I noticed one of my test pieces was splotchy from fingerprints. If AK were a little more interactive, we would see a tutorial and more information on their website. Kimmo
NOV 21, 2014 - 04:55 PM
Looks interesting
NOV 13, 2016 - 10:42 AM
I just prime the whole model with either Mr Surfacer or Tamiya Fine,plastic,PE,resin,and metal.Works well enough,never had any paint adhering problems.I like the AK track blackening fluid,but this stuff seems unnecessary to me.
NOV 13, 2016 - 12:11 PM
Thanks for the review, informative and amusing
NOV 13, 2016 - 01:30 PM

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