No matter what kind of material you’re using- whether it’s wood, plastic, metal or anything else- you will surely use an abrasive at some point while you’re creating a scale model. Abrasives help smoothen rough surfaces and edges so a particular part is perfectly shaped in preparation for painting and finishing.
Abrasives are a staple in every scale modeler’s tools arsenal. But just like the other tools and adhesives that are used in this hobby, abrasives also come in different types. There’s an abrasive for every kind of material or situation and you need to know which one to use to produce a smooth finish.
To help you learn more about abrasives, we’ve created this guide that we hope would make you more knowledgeable about this vital tool.
Pay Attention to the Grading
There are different types of abrasive “grading” and the type that you need depends on the task that you’re planning to work on and the result that you want to achieve. Abrasive grading is identified by the particle size of its backing material which is usually made of paper or cloth. Below are the typical abrasive grading available:
- extra fine
- extra course
There are also subgrades available which are gradings in between the ones listed above. Furthermore, the spacing of the particles in the backing is also used in grading abrasives. If you want to smoothen a surface that has already been painted then you need to use a wide spaced abrasive also known as an “open coat” type. On the other hand, if you want to cut something fast then you will need to use “closed coat” abrasives which are identified by the grains that are tightly-packed in the backing.
The Common Abrasive Types
There are many types of abrasives available for scale modelers to use but it’s important to remember which ones are going to work best for specific tasks and situations. Here are the most common types of abrasive that modelers use:
- Sandpaper- You might be thinking that sand is used to make this product but nowadays, it already uses more effective abrasive particles like silicon carbide and aluminum oxide. And it’s the latter that’s most commonly used because of the wide range of grits that it has which can be used to smoothen wood and metal. On the other hand, silicon carbide is available in grades that are coarse enough to be used for a wet application.
- Cloth and Emery Paper- These types of abrasive is great for flat surfaces and is used mostly to polish metal. It is versatile and strong enough making it capable of making tightly-curved metal surfaces smooth and shiny.
- Garnet Paper- If you’re working on a wood medium then you need this type of abrasive. It features grits that are harder making it suitable for achieving a fine finish. It’s also great for shaping both hard and soft woods like plywood or even balsa.
- Wet and Dry Paper- As its name itself says this abrasive is great for both wet and dry applications. If you have plastic or wood that needs shaping and smoothening then this will also do the job just right. Apply water to it and it’s capable of giving a finer finish. When used in wet applications, you’ll need to regularly wipe away the slurry that it produces. It’s also recommended to dip the abrasive into water every now and then to clear away any material that’s left which could affect its abrasive property.
Finishing the Surface
Finishing is one of the most important stages in scale modeling especially if you’re working on projects that depict planes and some famous warships. One technique that you can apply to effectively remove blemishes and unwanted scratches, marks, and other imperfections are by using fine abrasive grades progressively. Once the surface is smooth and free from these marks, it is time for you to apply varnish or paint.
When it’s wood that you’re working on, remember to sand parallel to the direction of the grains and not across. This helps prevent unwanted scratches that are not visible during the sanding process but would later show up after you’ve applied paint. If you want to use clear varnish then be sure to make the surface damp first to encourage the fibers to rise. Wait for the wood to dry and once it does, you can start sanding it with the finest abrasive available.
For open-grain wood like balsa and others, it is good if you first apply sealant so that the grains are filled first. Once the sealant has soaked into the wood and has dried, you can do sanding with a fine-grade abrasive then repeat the same process one or two times more using even finer abrasives every time to ensure a smooth and even finish.
Plastic materials don’t have grain so you can sand it to whatever direction of your choice. Using metal polish to make the surface shine also results in a smooth finish but you can apply it only after all the undesired marks and scratches are removed.
How to Sand using Abrasive-Wrapped Wood Blocks
For scale model projects that involve large and flat surfaces, using a sanding block will help achieve the best results. It is more efficient and effective when done this way and avoids unwanted results like hollows on certain parts that commonly appears when sanding with fingers. Make a strip of the right grade abrasive then have it wrapped on a block of wood which is of your desired size and do the sanding as normal. When sanding edges, keep the wood block level on the surface to avoid rounding the sharp sections.
Sanding Small Materials and Objects
For smaller parts that can’t be sanded using the methods discussed above, you’ll need to use a different technique. Just dampen your finger in order to pick the desired part then smoothly rub it against the abrasive material. For small plastic parts, you will need to use wet-and-dry paper to achieve the best results.
Learn This Basic Scale Modeling Skill
As you can see, knowing some basic things about abrasives and learning how to use every single one of them is a skill that every scale modeler needs to possess. Not only it ensures good quality, it also prevents errors and mistakes while in the process of building a scale model. Do you use abrasives in your projects? What kind of grade do you choose for certain situations? Please feel free to share some tips with us by posting them in the comments section below.