Plastic Model Aircraft Kits Recycling

For those of us who have been building plastic model aircraft for a long time, the obvious question is, “What do I do with the older models I built in the past before I reached by current skill level?”  The usual answer is, “Throw them out or maybe give them to the kids”.  

This is what most of us did over the years, but about 20 years ago, when I was pruning out my model display cases of models that no longer met my standards, I decided to disassemble them and store them in plastic bags with the idea that they might become useful many years later.  Of course, most of us saved some of the components, such as wheels, engines, props, etc., but I came up with the thought “Why not rebuild the kit to modern standards?”

One major factor is the condition of the kit.  In years past, we didn’t have the excellent glues and solvents that we have today, so kits were relatively easy to break apart.  If we had used Tenax or Microweld then, it would be virtually impossible to break a kit apart without doing some very serious damage. But with the old tube glues, breakdown is relatively simple.

Another factor is the paint.  I’ve always used enamels, and enamels, even when airbrushed on, can be removed provided the proper method is used.  Fortunately, years ago, I heard from some local IPMS’ers that standard automotive brake fluid was an excellent emulsifier, and that it would remove paint from styrene plastic without hurting the plastic itself.  I tried it with mixed results, and the idea languished for a long time.  A few weeks ago, however, I decided to try it again, and see what I could do.  I had an old bottle of brake fluid in my workshop that I had bought at a yard sale for fifty cents, so I figured that I would see how the system worked. I don’t know how this would work on lacquers or acrylics, as I’ve never used these.

The big question now was equipment and materials.  In addition to the brake fluid, I assembled an old hospital pan that I’ve had for years, some old toothbrushes, a pair of metal tweezers, some storage jars, an Xacto knife, a scotchbrite scouring pad, some paper towels, a couple of flat plastic drawer organizer trays, some round toothpicks, a few wooden coffee stirrers, and some pipe cleaners that I normally use for my airbrush.  I also got a cheap kitchen strainer.  Now that I had much more than I would actually need, I started the trial.

I had several old Frog Fokker D.XXI kits that I built many years ago, including one that a friend had given me that he had used as an airbrush  paint test target, shooting a bit of paint on it before painting the model he was actually painting.  This plane must have had twenty coats of various colors, ranging from silver to red to black.  I figured that if this method would rejuvenate that model, it would work on anything.  I was ready to begin.

The Process

Keep in mind that this is an extremely messy process.  Brake fluid has the consistency of light motor oil, although it seems to wash off with soap and water.  Do this step in the process outside, in the garage, or in a workshop.  If you  are married, and want to stay in that condition, DON’T do it on the kitchen table or sink.  If you’re single, the choice is up to you.

First, I filled the pan with some brake fluid.  It doesn’t have to be full, but it does need to cover the parts being treated.  I then dumped the parts into the pan, and allowed them to soak overnight.  The next day, I began the paint removal process.  In the case of the heavily painted Fokker parts, the upper coats just peeled off, but there were plenty of coats remaining. It took three or four soakings to get all the layers of paint off, but most normally painted models only require only one or two treatments.  I spread several layers of paper towels on my workbench, and went to work with an old toothbrush.  It was pretty slow going, and I would have given up except that I decided to try using a scotchbrite pad.  I recalled using these years ago in cleaning the residue of a gasket off of a cylinder base on the airplane engine, and found that it was a strong enough abrasive to clean off the gasket material without scratching the aluminum.  When I tried it on the plastic, it worked perfectly.  I just had to rub it briskly, much like using sandpaper.  It took the paint off but left the surface detail.  For hard-to-get places, I used a toothbrush.  It took a little more time, but it wasn’t long before I had a virtually paint-free kit that I could rebuild into a state-of-the-art model. The key to the abrasive pad is that it has to be hard enough to remove the paint, but not as hard as the plastic. Have several pads available, and cut them into four or six sections.  They’re easier to handle that way.  Also, you might want to trim off as much of the sponge backing as you can, as it is useless in the process.

Once the paint was removed, I dumped the parts into another pan, using the metal tweezers to pick them up out of the fluid.  It is a lot cleaner than using your fingers.  I then took the pan inside, and filled it with hot soapy water.  After soaking the parts in hot soapy water for half an hour or so, I gently rinsed them off and set them on a folded paper towel to dry.  The next morning, my parts were ready to use.

Lessons Learned

I found this to be a good way to begin the restoration process on old models, especially those that are still basically good kits but are hard to find or expensive today. It also works for items you have taken from the spares box and want to reuse.  I found that the better brand of scouring pads (NOT steel wool) worked better than the dollar store variety.   Any brand of brake fluid should work, but I have not tried other materials, such as oil or transmission fluid.  I don’t know about the toxicity of the stuff, but I haven’t started mutating  into a giant green cockroach yet, (some may dispute this.) so I think I’ll be OK. Let’s just not tell OSHA, or they might send out some TSA types, and you know what that can lead to.