The Finish: Sanding It Smooth!!

I didn't really like Test Panel #1 so I decided to create Test Panel #2 to test out a new finishing process. It came out pretty good (but didn't photograph well) so I decided to use this process on the pink panels (except the back one). I want to achieve an "automotive/piano" finish on the sides and front of the cabinet and Test Panel #1 just wasn't going to cut it. The polyeurathane top coat came out a little too streaky for my tastes (although it's probably due more to using improper supplies than anything else) and it just didn't have that extra special quality that I was striving for on this cabinet. This post will explain the process I went through in finishing the pink panels as best as I can. Two things right up front:

1. This process is a huge pain and is taking a very long time to complete.
2. Anyone who is interested on how I got the cabinet to turn out like it did should read here first. This link goes into pretty good detail about how to achieve a mirror finish on an MDF surface using automotive supplies. I followed this guide as close as possible.
3. For 99% of the sanding I used a Makita Palm Sander. It is worth every penny - your arms will fall off if you try to sand this project entirely by hand.
4. After sanding I always used a tack cloth to remove the sawdust left behind before applying another coat of paint. I highly recommend doing this.

The first thing I did was sand the surface of the MDF with 600 grit sandpaper. MDF is flat and smooth but not nearly as flat and smooth as it needs to be in order to start the finishing process. It's hard to believe but trust me on this one. After you go over it a few times with some 600 grit sandpaper you will not believe the difference.

The next step was to "seal" the MDF because the pink paint I applied is water-based and MDF will soak up water like a sponge and basically ruin it. I applied two coats of an oil-based primer to seal the MDF - other people suggested watering down some Elmer's glue (like 80% water to 20% glue) and slapping it on there to seal it once the glue dries but I was too much of a wuss to try it out. The oil-based primer worked great on my test panel so that's what I went with.

After the primer dried I sanded the entire cabinet smooth using 220 grit sandpaper before applying the pink paint. I applied 6 coats of pink paint and sanded in between with 220 grit sandpaper (except for the last coat). Then I applied 25 coats of spray lacquer as I described in an earlier post.

Now comes the "fun" part. Once the lacquer fully cured (over a two week period) I sanded it down to a super smooth surface. I spent 5(!) hours sanding one side of the cabinet. Five hours. One side. I used 1500 grit sandpaper, a palm sander, and a sponge. This is the sandpaper I used:

I divided the panel into thirds and spent about an hour and a half wetsanding each third. I'm still not finished with it entirely. I can still see a bunch of reflective sparkles all over the place when the light hits it just right - these are small divots that are still present even though I've sanded like crazy. I don't know what to do next - I'm debating whether or not to continue sanding this week trying to remove the tiny divots or if I should move on to the rubbing compound and polish. I'm not so sure the rubbing compound does anything to be honest - I applied a bit to a lint-free rag and started rubbing it in and I didn't notice a difference at all with the finish. The divots were still there.

Also, there are some sections that are starting to appear duller than others - I'm not sure if the dull sections indicate that I am getting the finish I want (and I just have to keep sanding) or if they indicate that I've completely sanded through the lacquer and I'm sanding the pink paint. The last thing I want to do is sand through the paint to the white primer or worse, the MDF. I am quite frustrated.

However, as it stands now (without rubbing compound and polish) it looks very nice from across the room (or even right next to the thing but if the light hits the cabinet just right you can definitely see imperfections which are making me nuts). I'm probably the only one that will notice them... or maybe I'm not - I don't know.

Check it out:

There are some places that look amazingly smooth and flat and others that have the divots no matter what I do. I've attached some pics of what I did (the sideart is just laying there). As you can tell from the pictures, the finish is quite flat - not a brush stroke to be found! I am going to go over it with 4-5 coats of rubbing compound and then top it off with 4-5 coats of polish/wax just to be safe. This is definitely hard to do and I have a whole new level of respect for people who finish cars (and pianos) for a living - you need some serious talent and experience!

Stay tuned for the polished/waxed panel!