The Complete Guide: Painting a Sparkle Top Rhodes Mk I Harp Cover

Started by Yaniv Brener, August 19, 2020, 01:28:54 AM

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Yaniv Brener

BIG post ahead: my full step-by-step guide to painting a Mk I harp cover with metal flake & candy paint for the sparkletop look.
I know, I have a different thread on painting open. Call me a neat freak but I like putting the complete guide as first post so it's easier to get to.

I had an extra cover I got off Craigslist and wanted to try the sparkle top look (think early Rhodes, Rhodes bass.) I don't have the money to invest in a professional painting setup or to pay a custom auto design shop, so I had to go the DIY spray-can route.
I don't have experience doing paint jobs, so take this with a grain of salt, but I'm a decent Googler so I found all the info I possibly could (incl. this site, hot rods, model rockets, guitar painting, Youtube, etc.) Just want to pass along what I learned, including tips of how I'd do it better the 2nd time around, and consolidate info into one big thread.

Cost: It's cheaper than a professional job, but it'll still cost you around $150-250, depending on what materials & tools you already have.
Time: Before you start, know this is not a 1 weekend project! It's a lot of work and you need space set aside. Also, there's also no changing your mind once you've started...can't undo sanding.

The project should take 3 "real" work days once you have all materials and a space to work in. However, note that there's also multiple days of drying downtime in-between.

Day 1 = Prep + Primer: sand flat all texture on the ABS plastic, cleaning, and primer.
Waiting period 1 = To be cautious, I waited 24-48 hrs after primer to make sure it was finished off-gassing; apparently, some people have had issues with bubbles cracking thru the base coat because the primer wasn't totally cured.
Day 2 = Paint: apply the base coat, metal flake, optional candy, and clear coat.
Doing it all in one day is the preferred method for many custom car painters, seems to be the way to get both chemical and mechanical adhesion btwn layers (if you wait a few days, the previous layer will have cured and you'll only get mechanical.)
Waiting period 2 = Clear coat needs to cure and harden. I've seen mixed info on how long it takes; consensus seems to be if you spray high quality 2K clear coat with a gun, it can be as fast as 24-48 hrs. With a 2K spray can, you may want to wait longer, maybe even 7-10 days.
Day 3 = Polish: wet sand with very fine grit and buff out the scratches with polishing compound. This removes the 'orange peel' effect in the clear coat and leaves a mirror-like finish.

Painting Tips:

  • How many spray cans do you need? For me, it took approx. 2-3 cans each step to get 1 tack coat and 3 medium-to-heavy coats on. 3 will give you the right amount for everything, with a tiny bit extra for mistakes.
  • What color base coat? This basically affects how light or dark your final product will be. I tested metallic black and metallic silver and liked the silver more - it looks a bit too light in the sunlight, but my piano will live inside where it's dark. You can use a white base to lighten it even more, or gold to give it some warmth. If you aren't going to spray candy, match the basecoat to the flake color which helps uneven application look more even. Personal preference goes!
  • Go for high quality paint, and preferably buy from the same company. I didn't follow that advice and got some weird bubbling issues with the first primer + basecoat I used that I had to sand down and restart (but it all turned out OK in the end.) If you do decide to get cheap primer and basecoat, at least pony up the cash for good flake and/or candy paint. Some nice companies are: Roth Metal Flake, Kustom Canz, DNA Paints.
  • NEVER sand in-between paint coats - it's before base coat and after clear coat only.
  • Better to wait too long than too short between coats IMO - heavy coats should get at least 15-20 mins instead of 5-10 (or even 30-60 mins, esp. if it's humid where you spray)
  • Practice on some scratch surface to get the spray technique down. You want long strokes and uniform distance, nozzle straight 90 deg. to the surface, overlap each stroke

- 3 cans of Rustoleum 2X flat white primer (Rustoleum's Filler Primer would also work, but it was sold out when I needed it)
- 3 cans of Rustoleum Metallic Silver for base coat
- 3 cans of Roth Metal Flake All-In-One (color: Why-It-Purp) - Note: in hindsight, I would have bought separate cans of Roth's base, metal flake and candy - this would be more work and $$$ but you'd be able to add more sparkle and layer different colored candy over your base & flake.
- 2 cans of SprayMax 2K Clear Glamour. This is THE clear coat standard, don't buy 1K. Get 3 cans, you'll use it: I wish I had. It's a 2-part mix; once you "crack" the can to mix in the hardener, you have 48 hours to use it.
- Optional - a spray can holder/grip. I didn't have one but it would have been nice. Plus it's reusable.

- Random orbital sander
- Sander disks: 80, 120, 150, 220-grit
- Sandpaper: wet-or-dry 1500, 2000-grit

- Soft sanding sponge
- Scotchbrite scuff pads
- Microfiber cloth
- Tack cloths - optional but DON'T get cheap ones, I did and they left sticky residue and fuzzies all over >:(
- Bucket of water and some dish soap
- Respirator, gloves, goggles - paint and ESPECIALLY 2K clearcoat is bad news for your lungs
- Optional - painting booth (legit or janky canopy + plastic sheets)

- Dual action polisher/buffer (or rotary polisher), sorta optional - see Day 3
- Wool polishing pad
- Polishing compound - Meguiar's

Pre-Day 1: Area Prep

I built a crappy painting booth in the garage with a canopy and some plastic sheeting. It was definitely not airtight and I had some dust getting in, but it's better than nothing.

Day 1: Prep & Primer
This is actually the most important step! I didn't take the time to perfect my primer and regretted it during painting.

  • Using the orbital sander & the coarsest grit paper, start sanding down the cover to remove all texture. Be VERY careful on the edges: it takes almost no time to flatten the curve (COVID pun intended) and screw up the profile.
  • Move up the grits until 220, try to wipe off dust regularly, and get it nice and smooth.
  • Clean the cover WELL with water and a few drops of soap. You can use a microfiber cloth to dry it. If the surface is super static-y afterwards and dust is sticking, I tried this trick: filled a spray bottle with 1/3 isopropyl alcohol and 2/3 water and gave it a light spritz + wipe down. Seemed to cut some of the static.
  • Now the primer: spray it evenly, starting with a light tack coat. The can will tell you ideal recoat times. MAKE SURE IT'S EVEN! I cut corners here thinking my paint would cover it up, and it was a huge mistake. If you see rough patches, or crackly lines as though the texture wasn't completely removed, sand it down and restart. *sigh*. It's a huge PITA, but trust me: it cannot be fixed later.

Waiting Time 1
24-48 hours for the primer to off-gas, as explained in intro. Try, if possible, to keep it non-dusty.

Day 2: Painting
Clear the schedule, this is a long day! Ideal conditions are 70-80 deg, no direct sunlight, low humidity if possible.

  • Prep: Give it a quick wipe down. Then, using the Scotch Brite pad, scuff the primer evenly so the paint can adhere properly. Finally, wipe it off again with a lint-free cloth or tack rag and make sure it's clean.
  • Base: Shoot your base coat - 1 light tack coat, then 2-3 mid to heavy coats. It's desert here so I waited 7-10 mins for the tack coat, 12-15 mins between coats. Don't go too heavy! You'll get runs and/or the paint might not flash off before the next coat.
  • Flake/Candy: After waiting at least a good half hour, time for flake (& optional candy.) I used an All-In-One rattle bomb from Roth Metal Flake - doing it again I might buy the flake and candy cans separately. The All-in-one instructions say 5 coats for a real deep look. 1 of the 3 cans I bought didn't work so I only got 1 light coat and 3 full coats.

    Note: If you're doing flake & candy separately, this step is 1. metal flake (as many coats as you like sparkles.) 2. Optional: 1-2 clear coat layers to bury the flake. If you do this, wait 24-48 hrs for the clear to cure. 3. 3-5 light-med coats candy paint. Seems candy paint is notoriously hard to spray without getting uneven 'tiger stripes.' Good news is you don't NEED to use candy if you match the base and flake colors, just shoot extra clear coat layers to bury the flake as deep as possible.

  • Clear: Last is the clear coat to bury the flake and really make it glossy. Wait a good 60-90 mins after the previous step. 3-5 coats is recommended - the more the better. DON'T do a tack coat with this, each layer should be even and full (but not TOO wet or it'll run, careful on the vertical sides.) It sprays very differently from paint, so test it out on scrap first.

Waiting Period 2
Mixed comments on how long this takes...I've seen 24-48 hrs up to 1-2 weeks to make sure it's fully cured. You could call Roth Metal Flake (super helpful for other questions I had) or a custom car shop for advice.

Day 3: Polishing (optional?)
Disclaimer - I haven't done this yet, as I left on a roadtrip before I had the time. This is the step that removes the orange peel from your clear coat and leaves the surface smooth (check out my pics - it looks like the surface of an orange where the light catches it.) I say optional because after the clear coat, it's already glossy and sparkly - the only thing missing is the professional smoothness. Honestly, I may leave mine as is - I'm too afraid to sand/polish and potentially screw up the whole paint job.

  • To start, get your bucket of water + drops of dish soap ready. Also, a sanding sponge, your 1500 and 2000 grit paper, and the rotary polisher.
  • Start wet sanding the surface with 1500 grit - use the sponge, keep it wet, and switch up your directions. You should feel less orange peel as you go. Don't overdo it and don't do the edges: if you sand through the clear, you'll screw up your paint job.
  • Move up to the 2000 grit and repeat. The lid will lose all its gloss and look dull. Don't worry, that's normal.
  • Clean off the lid with plenty of water and a sponge or rag, then dry it.
  • Then, using the polisher/buffer at a low RPM (~1000-2000) and plenty of buffing compound, start moving around the lid in circles, making sure to keep the pad horizontally flush with the surface, never on its edge. Don't stay on the same spot too long and don't buff the edges - you don't want to burn through your clear!

You might be able to polish by hand, but I'm not sure tbh. It would take a lot longer, that's for sure.

And that's it! If you polished enough, it should go back to being glossy and now the surface will be smooth. Your custom sparkle top Rhodes lid is done!



This is awesome, and a great reference.  I wish you did the finish on a scrap piece of wood so you could test the final buffing technique.

I wonder what other things around the house we can paint metallic purple... the refrigerator might look good.



Hey, I did my mk II using similar technique. I removed all the orange peel texture but didn't address the imperfections (they look like wrinkles) did you address them? I may go back and redo it (I used a rainbow flake over black and may do a different base). I'm thinking bonding glaze, assuming it's compatible with plastic.