I mentioned I would summarize my build/finishing process.... When I started this project I decided to document every step (photos) so that others may benefit form all the ideas and suggestions from Forum members, and most of all learn from my mistakes.
If you follow my build from the beginning you will see quickly I am from the "Cheap and Cheerful" school. My construction process is pretty well documented, but my finishing methods were a lot of trial and error. So... I will describe them in a little more detail.
After getting the cabinets glued together and rounding all edges which I agonized over because it's not a conventional speaker look. However, I am happy with the look.
I decided to paint the cabinets/stands. MDF sucks any finish like a sponge and it's well known the glued butt seam can show through almost any finish due to seasonal humidity changes. I have a lot of experience using epoxy in boat building, and decided to try it on this build.
Piano black look was my goal, so I tried a couple methods to fast track the process, and learned a lot along the way. On the stands I used Black India Ink (alcohol based) To stain the MDF. It works great with just one coat, and I highly recommend doing this first step on raw MDF if painting with a dark color such as black.
The next step I rolled on epoxy thinned 10% with lacquer thinner on the cabinets that were not first stained with the ink. Not staining first was a mistake as it added more steps later. The stands were also coated with the thinned epoxy. The epoxy soaked in easily on the MDF.
My original goal was to try to get the color buried under the epoxy and just finish with a clear coat of some type, and buff. However, I had failed to pre-stain the cabinets I needed to get the black color on them without resorting to paint. I tried a couple methods I have used in the past. one was using a special black colorant in the epoxy. It doesn't cover like paint, and the raw MDF was still showing.
The next thing I tried was adding graphite powder. This works a lot better, but it is a grayish black color, not the deep piano black I is was looking for.
The stands were a lot easier to get the nice black color because of the pre-staining with ink. The epoxy really hardens the MDF making it like hardwood. I rolled and tipped 3 colored fill coats after the initial thinned epoxy coat. I sanded between each coat, but I had problems sanding through to the raw MDF in small spots which required more color fill.
When I finally got a nice black color I did the final epoxy sanding. The next step was applying Zinsers SealCoat (shellac). I tried wiping it on, but on the cabinets it dried so fast, it was difficult to get smooth. It worked better on the stands. I used the shellac as a transition primer for the next step, and because I could build several coats in one day.
The next product I tried was Minwax Clear Polyurethane I had left from floor finishing. I applied 3 coats of the poly, sanding between with 320 dry. I couldn't get all the brush strokes to sand out to my liking, and I couldn't take them outside to try spraying the clear because it's winter!
I made a decision that turned out to be a good one. I bought a single can of gloss black spray paint from HD. I was able to apply 3 coats of this black spray on the cabinets and the stands in one session without sanding between coats. One single rattle can did 3 coats on everything! I let them harden for a week.
Having had experience wet sanding and buffing soft finishes in the past, I decide to try some methods I use in boat finishing. Soft finishes such as regular spar varnish are easily sanded with very fine paper. I immediately started wet sanding with 1000 grit 3-M paper, and followed with 1500 grit wet. The surfaces were smooth and free of defects.
I have a Porter Cable random orbit detail buffer I use for my car care. The buffer uses foam pads of various density depending on the product being applied which can be compounds, polishes, glazes, and waxes. I opted to try Mcguires Ultimate Compound which turned out to be perfect for this paint finish. This product is designed for restoring older car finishes. Normally one would follow with a polish, glaze or swirl remover before going on to a wax.
To my surprise, The compound was all that was needed to get a mirror finish before waxing. I tried Minwax paste wax (for wood finishes), but I wasn't satisfied with the result. It slightly dulled my perfect mirror finish. I resorted to a liquid automotive wax. I know most auto waxes contain silicone and can affect refinishing, however, chemical wax removers, and wet sanding has always worked for me in the past removing auto waxes. This wax brought out the Piano finish I was looking for.
In conclusion:
On future builds if I want a piano black finish I will do the following....
- Stain the raw MDF with black India Ink
- Apply 1 or 2 thinned coats of epoxy to seal the MDF
- Apply 2 not thinned epoxy coats, sand smooth
- Apply several coats of Seal Coat, sand smooth
- Spray multiple coats of a clearcoat finish, wet sand smooth with 1000/1500
- Buff with Ultimate Compound, finish with wax, DONE....
Larry
