You have a huge gap that needs to be filled on a plastic model, but no green-stuff or miliput on hand. What do you do? Make some “sprue-putty”!

This is the first of a series of hobby related article that I will post. In this tutorial, I will show how to use plastic model sprue as gap filler for plastic models.

Green-stuff, miliput and especially brown-stuff are expensive. Much too expensive for general gap filling on large plastic models. Other compounds exist, like squadron gap filler, they are often expensive as well. If you are a penny pincher like myself, try this method of gap filling.

What this will work on: This process will work on any PLASTIC model kit.

What this will not work on: It will not work on metal or resin models.

What you will need:

• A metal sculpting tool of some kind.
• A sharp hobby knife.
• A suitable cutting surface.
• A glass jar or container.
• Liquid plastic model cement (super glue WILL NOT WORK).
• Some spare plastic sprue (we all have this).
• A plastic model that needs gap filling or correcting.
• A well ventilated working area.

Step one.

Identify the gaps and regions to be corrected and filled.

Here you can see the gap down the centerline of this Eldar Warwalker.

Step two.

Chop up some plastic sprue. I prefer to slice it thinly from the the sprue frame, as shown above. If it is not fine enough, the whole process won’t work. It needs to be thin and small enough to be dissolved by the liquid plastic cement. Then place it into your glass container.

Step Three (the smelly stage).

Add some liquid plastic model cement to the chopped plastic. Add enough for the shopped plastic to get completely wet. Let it sit for a minute to two minutes, stirring it around with your metal sculpting tool occasionally. Once it looks like thick paint, you are ready to go.

Step Four.

Smooth the “putty” over the gaps to be filled. Be careful around details, as this stuff will destroy it. Also, don’t add too much at one time. Large areas will require several applications of the “putty”.
Next, let it cure overnight.

Step Five.

Sand the cured “putty” smooth with whatever method is comfortable or easy for you.

Post Notes:

This method has its limitations. Large areas cannot be filled in one application, as the plastic model cement would simply melt too much of the model area intended to be filled. You can “pile” more of the compound onto an area that has already cured (at least overnight).

Also, only mix as much as you are going to use. You can’t really save it for additional uses.