How do you deal with overhangs and supports when sanding and painting ABS prints?

1 Choose the right supports

When printing a model, the shape, size, and complexity of it can determine the type of supports that are needed. Grid, line, and tree are some of the most common options. A grid is a lattice-like structure that covers the entire overhang area, but can leave more marks on the surface. Line is a series of thin vertical lines that connect the overhang to the base, but may be harder to remove and may break the model. Tree is a branching structure that only touches the overhang at specific points and is more flexible and precise, but may require more slicing and printing time. You can adjust settings such as density, angle, distance, and interface layers in your slicer software. Experimenting with different options can help you find the best balance between stability and removability for your model.

2 Remove the supports carefully

Once your print is done, you need to remove the supports without damaging the model. You can use various tools, such as pliers, tweezers, knives, or cutters, but always be gentle and patient. Start from the outer edges and work your way inwards, avoiding pulling or twisting the supports. If the supports are too hard or stuck, you can try to soften them with a heat gun, a hair dryer, or some hot water. Be careful not to overheat or deform the ABS, and wear gloves and goggles for safety.

3 Sand the surface gradually

After removing the supports, you may still see some marks, bumps, or holes on the surface of your model. You can sand them away with sandpaper, but you need to do it gradually and evenly. Start with a coarse grit (80-120) and work your way up to a fine grit (400-600), changing the direction of your strokes every time. You can also use a rotary tool or a sanding sponge for more convenience and accuracy. Don't apply too much pressure or speed, as this can generate heat and melt the ABS. You can also wet-sand the surface with some water or alcohol to reduce friction and dust.

5 Prime and paint the surface

To give your model a nice color and texture, you can prime and paint its surface using spray cans, airbrushes, or brushes. However, you must ensure that the primer and paint are compatible with ABS and won't damage it. Popular choices include acrylic, an easy-to-use water-based paint; enamel, an oil-based paint that is durable and glossy; and lacquer, a solvent-based paint that is fast-drying and smooth. You can also apply a clear coat or varnish to protect the paint and give it a matte or glossy finish. Make sure to read the product labels for instructions on how to apply thin and even coats in a well-ventilated area. After painting, let the model cure for 24 hours before handling or displaying it.

6 Here’s what else to consider

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