Filling with plastic by Steve Bamford

Filling with Plastic

Tools 'n' Tips Article by Steve Bamford in 2002

Here's a handy little technique I discovered through some experimenting long ago.....I later discovered many people use this same simple technique.

There are times when you have damage done to a kit that conventional filler can't fix. A good example is the chunk taken out of the trailing edge on this 1/72 F-14 of mine. If I was to use conventional filler for this repair...eventually over the years due to handling...the chunk of filler would chip off. Another possible solution is to cut a piece of plastic sheet to fit the missing plastic. But then you'd have two slightly different types of plastic....one hard...one soft and the resulting work could be more than is necessary and the results far from perfect.

So the solution is to make your own plastic filler from the left over sprue of the same kit.

The first step is to clean the area of all paint and other foreign substances that could affect the bond of the repair....bare clean plastic is what you want.

Then take an X-Acto knife and shave off some plastic from sprue from the same kit. The reason it's best to use sprue from the same kit is the fact all kit manufacturers use different plastic....some are hard....some are softer plastic. By using the sprue from the same kit, you guarantee a perfect chemical bond between the kit plastic and the "filler-plastic" you'll be using for the repair.

Place the shavings onto either a clean metal lid from a tin can or on a clean piece of glass or mirror. I'm using a lid from a tin can, because it's easy to find at my house.

Take an eye-dropper and add a few drops of either lacquer thinner or liquid glue....do NOT use tube glue...it won't work. I'm using lacquer thinner for this demo, because it's cheap. Liquid glue may harden a bit faster....I'm not sure.

Using your X-Acto knife, stir the mixture around and after a minute or so the lacquer thinner/liquid glue will dissolve the plastic shavings and leave you with liquid plastic. Let the mixture thicken up for a few minutes if needed so it isn't too runny.

Take some of the liquid plastic mixture off the tin can lid with your X-Acto knife or putty knife and get ready to do some filling.

Apply the sticky mixture with your putty knife or X-Acto knife.

Apply a bit extra of this mixture to insure you don't have to go back and make up more of the mixture in a couple of days.

Once the mixture begins to harden a bit you can shape it with your fingers. This mixture can take up to 48 hours or more to fully harden.....so you don't have to rush.

After 36 to 48 hours and the mixture is as hard as the surrounding plastic of the kit, then you are ready to do some sanding. I will sometimes take a fresh new sharp X-Acto knife to shave down the filler to almost the same level as the kit part to avoid extra sanding. This saves

time and spares the surrounding kit plastic form excessive sanding. A good idea is to apply some scotch tape to the surrounding detail before sanding to protect surrounding detail such as rivets or raised panel lines from being sanded.

Finally I take my tiny modellers file and begin filing the liquid plastic filler to almost the same level as the surrounding kit plastic. At this point you're ready for sanding. I begin with a small piece of 400 grit sandpaper and sand till the filler is the same level as the surrounding kit plastic. I finish off the sanding with some 600 grit sandpaper to get a perfectly smooth finish . And that's all there is to it.

Steve Bamford

Below are a couple of before and after pictures.


Before	After