HOW TO PREP FOR PAINTING
Mel Miller Equine Art decorator finish medallions come ready for display, but unpainted medallions and models need a little work prior to painting. For a long lasting and beautiful finish, models must be prepped. You will need the following items:
Bar Keeper's Friend cleanser - the bottled liquid is more convenient (and possibly more effective), but the powdered version works as well
Toothbrush for scrubbing, and for faster work a nail brush
220 grit and higher sandpaper, micro files, carbide scrapers from Rio Rondo and Kelly's Studio, and any other helpful sanding tools you like - sandpaper wrapped around a cardboard nail file is one of my favorites
Primer such as Duplicolor sandable automotive primer
Filler such as Vallejo Plastic Putty
Two part epoxy putty such as Aves Apoxie Sculpt - I find blue is the most workable color
*Safety first! ALWAYS wear a respirator when spraying primer and when sanding resin, epoxy, and plastic. Wear disposable gloves when spraying primer and using epoxy.
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Step 1) If you're starting with a Breyer or other plastic model, use carbide scrapers and sandpaper to remove and smooth away the logo. If you are prepping a resin, leave the artist signature in place.
Step 2) Using your micro files, carbide scrapers, and sandpaper, remove seams. There is no one way to do this - use whichever tools work best for you! I prefer to first go over all seams with a scraper, follow up with a light sanding to smooth the edges, and inspect for any crevices where the micro files will do a better job than sandpaper.
Step 3) Resins have a release agent on the surface to assist in molding, and touching resin and plastic models with bare hands causes oily buildup as well. This coating needs to be removed before painting. The cleanser will severely dry your skin, so put on the heavy duty rubber gloves before scrubbing. Liquid Bar Keeper's Friend can be drizzled right onto the model, or if using the powdered version, mix it into a paste first with some water and then apply with the nail brush. Scrub thoroughly in every nook and cranny, being careful not to break fragile parts. Use a toothbrush to get into tight areas. If you're prepping a micro, a toothbrush is all you'll need!
4) Rinse well and watch how the water behaves. Anywhere water beads up, more scrubbing is needed. When the model is completely clean, water will sheet off the surface.
5) Always use gloves to handle the model after it is clean. You don't want to put oils from your hands back on the model after cleaning it so carefully! Inspect for any tiny areas than need to be filled with spot putty and any larger issues that need an epoxy repair. Only very small holes should be filled with filler putty - if you can fit a pencil tip in an air bubble, it should be filled with epoxy.
6) After following the label directions for your filler and epoxy repairs, feather the spots out to smooth, just like you did with the seams. Dust off and the model is prepared for primer.
7) Shake your primer can until the mixing ball begins to rattle. Set a timer for 2 minutes and shake vigorously. Do NOT guestimate the shaking time - you need the primer thoroughly mixed and without a timer it may seem like you've been shaking forever when it's only been 30 seconds. Put on a pair of disposable gloves and take the model outside to spray in an area protected from rain and dust. It is completely fine to spray in freezing temperatures as long as the can has been kept inside at room temperature.
The proper technique is to point the can to the side of the model first, press the nozzle, and then swipe over the model, releasing the nozzle at the end of the stroke. Do not hold the nozzle down and blast the model with primer! Spray in several light coats - a thick layer of primer won't cure properly and could crack, drip, or develop other textural issues. Spray difficult to reach spots first such as under the belly, between the legs, under the chin and tail. If you start with the easy to paint parts, then when spraying the more difficult areas excess primer will build up where you have already sprayed.
I like to spray the rear part of every model first, or the non-face portion of a medallion. That way when I come back to spray the second half, if I goof and touch primer that hasn't quite dried yet, it will be on a spot that's easier to fix.
8) After the primer has had several hours to cure (overnight is best), inspect for prepping flaws. Nicely cast medallions are often done at this point, but there will probably be many issues that show up on full models. Look at all the seams, check for air bubbles and any other irregularities, and repeat the sanding and filling steps. If the model has been handled only with gloves, further washing is not necessary, you can just dust it off and respray. Continue with the checking and respraying process as many times as needed, but try to address every single issue you can find each time to avoid building up too many detail destroying primer layers.
Medallions with decorator resin colors can be painted just like regular unpainted white resin. The prep steps are the same and they can be either fully coated in primer, or primered only in the places that will be painted, leaving the fancy elements of the resin exposed and part of the finishwork. Resin with large glitter pieces may have lots of surface bumps and are generally unsuitable for painting. Pearl-Ex/mica powder and very fine glitter is ok to paint over.
What about sodaglue? Sodaglue (baking soda sprinkled onto superglue for an instant set) is useful in some situations, like tacking pieces to each other during the customizing process, but it is very unstable. Over time it degrades and crumbles, even when covered with a protective primer layer. Holes filled with sodaglue might start causing problems in as little time as a year! It takes a bit longer to wait for epoxy putty to cure, but it is a far better long-term filler.