When it comes to casting metal, it has to follow the main industries that require this service, automotive, construction, and machinery. The only problem is newly made castings will have rough surface, burrs, or residue. Treatment surface post casting fixes this problem by smoothing the surface making it ready to use, more durable, and overall better. Below are some easy steps on finishing metal castings.
First, remove the melting surplus: Castings will have remaining risers and gates and will also have the rough burrs along the seams of the molds. You can remove the risers using angle grinders, chisels, and files, and burrs can be ground down. A handheld deburring tool will also be effective, specifically for small or delicate castings, because it will not damage the casting as it will work gently. Castings with sharp edges pose possible safety hazards and can alter the fitment of castings which is why this step is quick and necessary.
Next, clean the surface: Castings often have surface remaining oxidized rust like films, sand residues, or oils. The most common methods are:
Sandblasting: You can use a high-pressure stream of air to blow fine sand or other abrasive particles to the surface which will strip the dirt away as well as the black oxidized film. This works for large and irregular castings as well.
Wire brushing: This is accomplished by using a power tool or by hand as well and it is made for small areas or delicate castings that need light to moderate cleaning.
To get something extra clean, use a solvent like mineral spirits to wipe off any oils, and allow the piece to dry completely.
To smooth and polish the finish, use sanding and polishing techniques for parts which need a sleek finish for either decorative purposes or to meet precision use standards. Start off with the coarse sandpaper which is in the 80 to 120 grit range to take off any rough spots, and then use the finer sanding paper in the 400 to 600 grit range to get a glossy finish. In the case of polishing metals like aluminum or steel, you can achieve a mirror finish using a buffing wheel and polishing compound.
For added protection, apply a finish such as paint, powder coating, or galvanizing to stop rust or corrosion. This is ideal for pieces that may be exposed to the outdoors or in moist settings as it will keep the rest of the piece from deteriorating.
To enhance the metal castings for safety, functionality, and longevity, all you need are basic tools and techniques. If you are a hobbyist or a manufacturer, you will be able to take pride in the work you cast and know it is up to the expected standards.