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I'm building some speaker cabinets for my living room out of MDF. I'm wondering how to achieve that "high gloss" / "piano black" look, like on B&W speakers or, well, black pianos...
Any ideas? I'm pretty sure it involves lots of layers of lacquer, but does anyone have any specific advice to give - spray or brush, how many layers, surface preparation, what kind of topcoat?
I have used this guy's technique before and it works great.
Basically, you apply very thin coats, then sand to about 400 grit, and after that, do wet sanding to about 2000 grit, and then switch to the polishes.
There is a pretty complete step-by-step here
I think the link in LeeG's reply covers all the necessary steps but just to have it spelled out here.
Good surface prep is very important, imperfections 'telegraph' through paint very easily so the more perfect you can get the surface initially the better. The flatter the starting surface the less paint you have to use too, so it does have both time and cost benefits.
Build up of colour in multiple layers. Just as with most painting and varnishing multiple thin coats are better than one thicker coat.
Flattening off using a sanding block to maintain a good flat surface. Special care must be taken at edges and corners as it is very easy to sand through to the primer coat.
Final smoothing by wet-sanding to a very high grit, while still striving to keep the surface flat; it is possible to introduce waves and other dips into the finish even after switching to very fine grits.
Polishing. This can be achieved in any number of ways, from the old traditional methods used in furniture finishing such as using powdered rottenstone lubricated with a light oil or water, to modern cream polishing compounds and powered rotary polishers.
It seems nobody bothered to mention French Polish. Sigh. That is the standard piano finish for quality pianos, period.
French polish is a series of steps that fills and smooths surfaces using shellac.
Over a stained and filled (grain filler) prepared surface:
The first step uses rottenstone (like pumice) mixed with 1/2 lb or 1 lb cut shellac; rottenstone comes in grades (particle size). You work through grades of rottenstone + shellac from coarser to finest. The final multiple passes are shellac only.
The reason this is not used more often is not the quality of the result, but the cost of paying someone with experience to do it. Mass produced pianos would have to be finished in places where wages a far lower than Europe or The US in order to compete price-wise with other finishing methods.
I've touched up some baby grands and estimate that one square yard of surface is about two hours of work for minor touch up. I do not know firsthand, but am told a full grand piano can take 160 man hours or more for all finishing steps.
The good part about french polish is that it can be touched up to look completely new, but damage on nitrocellulose lacquer may require complete refinishing. By damage I mean spills, not where little Tommy takes a hatchet to a piece of furniture.
Pictures do the best job of conveying the idea: https://www.youtube.com/watch?v=LqYENoVuySo
I know this is an old topic but hopefully this helps someone out.
Painting MDF can be very frustrating. End "grain" in MDF will soak up paint faster than you can apply it.
Sand that with 320 then 600 then 1200. I use a tinted oil base primer. 3 coats block down with 400-600 and repeat until the end grain no longer soaks up your paint and has the same look as the face of the panel.
Now you can paint. I have had good luck using Nason 2 stage automotive paint (base coat/ 2k clear coat). The important part is before the paint.
If you're using MDF spray it with epoxy primer blocks sand it and shoot it with black acrylic enamel if it doesn't appear flat enough blocks and sand it with 320 grit sandpaper shoot it again then buff it this is far easier and faster I restore old wood boats
All high gloss pianos are polyester. They are not lacquer of ANY stripe, nor are they shellac. Neither lacquer nor shellac can look good for long, except they be cared for tremendously meticulously.
Polyester is a 100% solids, vastly harder than lacquer, and can be built ten times thicker than lacquer without cracking. It takes serious buffing equipment, and quite a learning curve.
For black, contact Allied International (http://alliedintlinc.com); for clear, find a nearby Duratec dealer. (Only Allied has a true piano black; others have a blue cast.)
