The ultimate guide you need to paint your prints and make more money with it.
The applications of 3D printing are increasing. Whether in industry, small businesses or private customers, the finishing requirements are varied. This implies that we must be prepared to decide whether to paint a part or not.
If you want to offer products with a great paint finish, you should read this definitive guide. With it you will be able to carry out the best jobs with incredible results.
Is it worth painting a print?
The answer to this question will depend on different factors. For example, if the added value that a painting process will give to the print corresponds to the effort and time it will take. Of course, the skill and ability we have to achieve neat and well-finished pieces will also have an influence. In this sense, it is important to mention that it is not necessary to be an expert to achieve great results.
As for the time it takes to complete this work, the quality of completion is directly proportional to the number of hours we will dedicate to the process. This equation is the inverse in terms of the size and detail of the printed figure.
On the other hand, we must take into account that we will need a space in our work line dedicated to painting. This implies to allocate a place with certain characteristics. Good lighting, away from air currents, a comfortable countertop and above all away from our machines, especially if we will work with aerosols.
Painting FDM Prints
If we have decided to start providing a painting service on printed parts, it is important to understand that the previous stage is as important as the application. For this we have prepared this guide, where you will find everything you need for the best finish.

Prepare the piece
The first step is to generate a design according to the level of detail we need. That is, the best finish will be achieved through a high number of polygons. This may mean a large file size, but a lowpoly part is more difficult to fill and the lines will be more visible.
The layer height also influences the result. Values higher than 0.15 mm can mean more preparation work. At the same time the thickness of the perimeters should be higher than in conventional prints (2 or 3 additional walls), especially if we choose sanding or a solvent as a smoothing method.
In short, the printing quality must be good, especially considering that we will increase the cost of labor and materials (paint). If you have problems with your machines, you will find in Bitfab all the tricks to solve them. In addition, we offer a printing service with guaranteed quality.
The next thing to do is to choose how to leave a smooth, blemish-free surface. The three most proven ways to do this are through solvent, clear coat or traditional sanding. Each of these ways will yield different results.
- Solvents. This is a more complicated process than the other two. Since we will have to take into account the type of filament we will use at the same time that we will need to increase the safety standards to do it. In the case of ABS, it is known that it can be softened with acetone applied in the form of steam or with a brush.
However, PLA is a different story, as we will have to use dichloromethane or methylene chloride, which can be more complex to achieve. Another equally effective compound is methyl trichloride or as it is more popularly known, chloroform.
In all cases, it is vital to have the necessary facilities, as well as all the safety measures to handle these elements, especially considering that they can be carcinogenic.
- Resins. It is a very good alternative to achieve a smooth finish and at the same time protect a print without sanding. It involves coating the part with epoxy or polyester resin. However, the preparation of this compound must be very precise, otherwise we could obtain an inadequate viscosity with an undesired result. For this reason, special products such as XTC-3D are available on the market.
- Sanding. This is the most recommended method. Above all, because you will have absolute control of the details. To leave a print ready for painting, we must also use a primer. This product will fill the spaces between layers, as well as any imperfection. The best option is undoubtedly an aerosol primer, it is easy to apply and can be found safely in paint shops. But, if it is a large piece whose imperfections require more filler, we can use body filler.
In both cases, after priming, we must proceed to sand with water progressively. Beginning with a grain not less than 120 and finishing with a grain greater than 400. Repeating the filling and sanding process will help to obtain a perfect piece.