Advanced Finishing – Spray Painting
The professional and advanced way of furthering your 3d prints. This isn’t a step by step guide on achieving a certain finish but simply an overview of the work-flow behind the crucial priming work needed for SLS Nylon prints. There are many online tutorials showcasing various techniques required at the painting stage and it is thoroughly recommended that you read as many as possible to gain a greater breadth of knowledge on the subject. These skills require practice and a keen understanding of what you are carrying out, often taking many years to master.
Equipment:
Sealing medium
Filler/High Build Primer
Sandpaper (Various Grades)
Standard Primer
Paints/mediums specific for desired result
Method:
Use the sealing medium to coat the model and remove the SLS Nylon porosity
Once dry give a light sand with a coarse grade sand paper (240 – 400 grit)
Apply filler/high build primer
Once dry sand down to achieve a completely smooth surface (400 – 1200 grit)
Apply standard primer
Apply your chosen mediums to achieve the desired result (see Painting and below for tips) Now this may seem a tad simple, however do not be fooled!
Tips:
A well primed model is essential to achieving a decent finish and therefore every bit of effort should be put into the initial stages. It may seem tedious to sit there for hours sanding every nook and cranny, and will often require several coats of filler primer and sanding sessions to get to a smooth, non-pitted surface but this effort makes the difference between an ok model and a stand out model.
The use of standard primer will help to show any blemishes or missed spots and provide a good layer for the main paint layers to key into. General practice is to use a white primer for lighter coloured paints and a grey/black for darker finishes and metal reproduction.
The difference between a paint job and well reproduced replica/model is all about how you approach the painting. Try not to think of it in terms of ‘just painting’ or simply adding colour, instead try to think about what material you are going to reproduce and the qualities that they possess which makes it identifiable as that material. This is where the use of matt, satin and gloss paints and other mediums has a huge impact and can often make or break the sense of realism.
If your model is a scale reproduction of a larger object, say a 1/24th scale car model, the finishes found on the full sized object won’t necessarily appear ‘correct’ on the smaller object. So what is a high gloss paint job would actually be closer to a satin finish on the smaller object. Carefully consider the subject of your model with relation to the actual physical 3d print and always use reference images of the real object to help guide your painting.
A lot of the knowledge required to know when and what types of paint and materials to use is gained through years of experience and experimentation, so don’t worry if you’re bamboozled from all there is on offer! Your local model shop should be able to help out with the basics and to give you a quick run through of the different paints on offer as well as the more specialist materials you can use.
This part has only the gold paint applied without any priming work carried out. You can see how uneven the paint has gone and that the original texture is very much predominant, resulting in a very unconvincing metal finish.
There is a use for this paint behaviour however as it is pretty handy in creating a stone finish. Careful dry-brushing with a lighter tone that the base layer will pull out the raised details adding depth.
Here is the same part but with a decent primer base down and after a good level of sanding work. You can see how much more convincing the smooth finish is and how even the colour of the paint has been subtly improved.
You may notice areas within the letters that are somewhat rougher than the external faces. This is due to the inability to get primer into those areas and to sand. This is just an inherent trait of painting complex pieces that have been printed with an SLS printer