Quick Plastic Flash Removal 

I am obsessive about removing all of the flash from my miniatures. When I got into Warhammer 40k, this become a liability because of the sheer number of miniatures to prepare. I was clued into a trick I could use with plastic miniatures by a fellow painter, Brian, on the Yahoo! group 'mini-painter'. He informed me about a type of cement that can be used to get rid of flash and mold lines. This helps a lot with hard to reach places where a blade is awkward and also in spots where the flash is minimal.

I would strongly recommend a combination of blade and cement. You should use a blade as usual on long smooth surfaces and easy to reach areas. You should also use a blade to reduce the flash in heavy flash areas. Ideally, the cement will be reserved for fine flash in difficult-to-reach and/or delicate areas in which a knife is hard or time-consuming to use.

What follows here is my current technique. You might find that Tenax alone works best for you. I want a nice clean model when I am done, so I use a knife for the bulk of the flash removal, but avoid hard to reach or fine areas that I might damage. I then go over the area with Tenax. I find that for me, using Tenax exclusively will lead to unwanted obliteration of details. The example that follows is the assembly and cleaning of a Gaunt model for the Warhammer 40,000 game (Games Workshop).

I'm Melting!

Keep in mind that, basically, you are locally dissolving the plastic in a controlled fashion, so excessive application of this will destroy details. On the other hand, you can use this technique to help smooth out regions where you have gouged or scarred the plastic with a file, knife, etc.


  • Tenax Cement* - and only Tenax Cement. I have not tried it with anything else and I was instructed to use specifically this cement.
  • Red Sable brush - yes, you are throwing away a good brush, but figure it's worth it. You are melting the plastic, so a crappy brush or a brush with too much spring will create more blemishes than it resolves. I use a 2/0, but you might want a finer or larger one as dictated by the features you are brushing. Using a big brush between two small closely spaced features will probably leave you with two smaller, smoother, farther spaced features.
  • Xacto Hobby Knife - You must have adult supervision! This is used to trim flash.

* - actually "Tenax-7R SPace Age Plastic Welder Super Fast-Dry Formula" :-)


  1. The limiting factor here is where I can reach with a hobby knife and a Tenax-coated brush. In the case of this model, I could assemble the body and head without compromising my accessibility, but the arms blocked the body, so I left them off until later.

    Trim mold lines and flash from long smooth surfaces where a knife is easy to use. In places like this, Tenax may do more harm than good by introducing disfiguring brush marks. Note that I am dragging the blade at about 75 degrees, not cutting into the material. I use light quick strokes so as to err on the side of removing too little flash rather than risking gouging the material. Fresh, sharp blades are essential. Skip knobby and hard to reach areas until you get to the Tenax.

    WARNING: YOU MUST HAVE ADULT SUPERVISION WHEN WORKING WITH A KNIFE! Trim off heavy flash, such as where the piece(s) connect to the sprue. Note that I have the base and handle of the blade firmly secured against my thumb to constrain the knife to a short, slow, controlled cut. Do not drag the knife along its edge, just press it slowly and gently towards your thumb; it's similar to pinching the piece it between your thumb and the blade. If you drag it along the blade surface, you will cut your thumb! This is dangerous for your thumb and the model, so be careful!

  2. By now I have cleaned the bulk of the flash off of the body halves. I cleaned the excess flash off of the head and assembled all three parts with Faller Expert Plastic Cement.
  3. Now it's time for Tenax. I like to get the brush well saturated by dipping and swirling it in the Tenax for 30-60 seconds. Dip the brush into the Tenax and scrape off excess once as you withdraw the brush.

    A picture of Tenax-7R Space Age Plastic Welder (I love saying that every time). Notice the cardboard square I superglued to the base. This is a safety measure to avoid tipping the bottle over, which can happen surprisingly easily and frequently when you get into some high speed flash removal. Also be aware that Tenax evaporates quite quickly. You should have a reasonably well ventilated workspace and you should buy a replacement bottle when your current one is about a quarter full. I personally move on to the next bottle when it is about 5-10% full as there is a slurry of flash and cement by that time.

  4. Brush across the flash, stroking perpendicular to the flash or mold line.

    This is where some art comes into play. You will need to practice this technique get it just right. The basic requirement is to stroke perpendicular to the flash line that you are trying to remove. If you come across a thick or heavy piece of flash, stop and use a knife to reduce it if possible. Tenax does not care what it melts and if you try to reduce a very heavy piece of flash from your models, you will likely obliterate some details in the process (See What Not To Do)


  • Practice on a piece that you don't mind ruining!
  • Use less glue and more brushing to reduce the flash.
  • Use more glue and less brushing to smooth a region out. The ultimate limit of this is just using the brush to deliver a large drop to the region and letting surface tension sort out the surface (i.e. no brushing).
  • This works best in hard to reach places and not as well on long smooth surfaces, where a good old knife is better.
  • Buying Tenax - I found it at both of the hobby stores I frequent, although one of them kept it behind the counter. I have been told that you can also buy it online from Micro-Mark (I have not used them and cannot endorse them).

Some Results

Genestealer's Back (normal flash in a difficult spot)

This worked remarkably well for the back. A knife would have either left bits unfinished or produced at least some small amount of scarring.

What Not To Do* - Genestealer's Head and Tongue (heavy flash and a step at the mold line)

On the head and tongue I left the heavy flash on there and used only the cement to remove it. This created quite a sheen to the areas treated. There was also something of a step at this mold line, and more cement was required. Of course, with a knife I would have ended up shaving/scraping down the step, so this approach left more of the plastic intact. Also note the tongue, which is exceedingly difficult to safely clean with a knife. What I should have done is use the knife as much as possible, then go with the cement.

* - You should reduce large amounts of flash with a blade or file first.

Hormagaunt's Body (Overall)

Hormagaunt (Close up)

Last updated 2004-03-24

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