Scratch-building Rounded Rivets

This is just a quick overview of a technique I used to add rounded rivets to my Stephenson's Rocket. The Rocket is an early steam engine from 1829. I am building this kit as part of an online group build called Iron Rails. The Minicraft kit leaves much to be desired and will require a lot of work to fix sink marks and excess flash.

This article isn’t about the kit; it’s about the rivets. The exhaust stack on the Rocket has a few horizontal rows of molded-in rivets. But the vertical line of rivets was omitted. I decided to add them myself and researched methods on how to do so. I didn't want to use rivet decals because the carrier film often leaves a ridge, which is not desirable for this project. I couldn't use styrene rod because the rivet heads must be rounded, and I didn't have much luck trying to round .020" rod by hand.

I decided to make the rounded rivets myself, using a template from Hauler (HQT013) used for making aircraft position lights. This tool is a sheet of brass with a few dozen holes of various shapes and sizes. The idea is to melt some clear sprue and squish it through the hole. The end result is a domed, tear-shaped piece of clear plastic you can use for your position lights.

In addition to the tear-shaped holes, the template also has some round holes of various sizes.  I selected the .6mm round hole as the appropriate size for the desired rivets. If you don't have this tool, you can still make rounded rivets using this technique. Just take a sheet of brass or other metal (about .006" thick) and drill a hole of the desired size.

I taped the template to a block of wood to support it. I drilled a hole in the block to allow the rivet to squeeze through. Then, I took some light gray spare sprue and melted the end of it over a candle. If you have ever stretched sprue, you know how this works. Once the end was softened, I just jammed the soft end through the desired hole in the template and let it harden (which only took a few seconds).  Once hardened, a rounded rivet head protruded through the hole. To remove the rivet, I used a chisel blade in my modeling knife to slice the rivet off, using a gentle sawing motion. I suggest making more rivets than you will need because you will lose a few.

Once I had a collection of about 10 rivets, it was time to glue them to the exhaust stack. I first made a spacing template out of masking tape. I marked the appropriate spaces using dividers, then positioned the tape on the stack.

Attaching the rivets required two hands. With one hand I picked up each rivet with a wet toothpick. With the other hand, I applied a small amount of Testor’s liquid cement to the stack. I chose Testor’s because it seems less aggressive than others. Use a small amount of solvent here, don't flood it. Use just enough to make a small shiny spot on the plastic. Once the rivet was in place, I applied pressure to the rivet with a pencil eraser (don't use your finger, you'll leave a fingerprint).

The end result is shown above. The new rivets stand out more than the molded-in ones because of the lighter color of the plastic. As you can see, I only needed a few rivets. If the model required hundreds of them, then rivet decals would be the way to go. This method may seem tedious, but it went very quickly and was tons of fun. Who doesn’t like to melt plastic!