Q&A for How to Finish MDF

MDF has excellent and uniform structural properties, but does not have the natural, beautiful wood grain appearance and texture of natural wood. The face of MDF is smooth and dense, and is easy to coat with paint or stain, while the factory edges (or any cut edges) are more porous and will soak up a lot of paint or stain. You can use a variety of paints or stains; the trick is to seal the MDF first, then build up layers of paint or stain. Both paint and stain can be finished with a gloss coat to make the MDF look like high-end wood. I stained an MDF tabletop with dark stain to simulate wood grain, then flood-coated it with tabletop epoxy.

You can stain it or paint it, but you want to be careful not to use a finish that will wear off on the thread. If you're not familiar with primer and paint techniques, a stain would be an easy way to seal the wheel and make it look beautiful. The tricky part will be getting stain into the triangular cut outs. The inside edges will soak up a lot of stain, so they will be darker, and it will be tricky getting the stain into the cut outs. The two outer faces will be easy to stain, and the thread groove will be easy to access, but will soak up a lot of stain. A hard gloss coat will seal the stain and give the thread groove a low friction finish.

Stain soaks in much more; it's meant to be porous, so stain is better. Paint sticks.

Staining adds the color to the wood. Top coats generally seal the pores so that other liquids cant get in. Liquids and condensation (even small amount) cause the surface to swell and wear unevenly with use. Some wood comes pretreated to resist rot or insects. These treatments may need to be removed (sanded) if you are staining wood where you want a professional finish. Sealants are things like polyurathanes, waxes, and some water based compounds. Some stains CAN included a top coat or sealants.

The “stain” process is primarily about appearance. It comes down to personal preference. It’s just a case of how dark do you want your work to look. More coats of stain the darker the job will look. The sealer is mainly about protecting your work piece once you are happy with how it looks. Keep in mind the sealer will darken the project just a little. A good idea is to keep a few off cuts from your project and stain them the same as you have done for your project. If you intend to do more of this type of work you can create sample pieces and label them with the number of coats. If you do this, ensure you make two samples for each coat you do, this way you can seal one and have the other raw.

Applying stain can be done by either brush or clean cloth. You may prefer to use a cloth, this process is quicker and easier and, at the end of each coat, just throw the cloth out rather then clean a paintbrush.