Updated: Jul 13
Sanding, Buffing and Polishing, is not always necessary. Sometimes a dome coat or a flood coat of clear resin is all that is needed. However, that is not always THE answer depending on project involved. Some projects require a bit more.
You can use a wet/dry sandpaper (use it wet with a tiny amount of dish soap) in course grit, down to the finest grit you can get. Then use a polishing compound to buff and shine the resin back to a glassy finish. Wipe it on with a cloth then hand rub it, or use with a buffing and polishing wheel.
There are many types of polishing compounds (these are just a few):
- Meguiar's PlastX plastic cleaner & polish, for automotive headlights.
- Blue Jewellers polish compound, often used on resin jewellry.
- Fabulustre is good. Some people use vehicle headlight polish on their castings.
- Another one mentioned to give a lovely finish on resin jewellry is a piano polish.
- Hut Ultra Gloss Plastic Polish many pen makers use.
- Novus 7100 kit, 1 (Plastic Clean & Shine), 2 (Fine Scratch Remover), 3 (Heavy Scratch Remover).
- Flitz, Metal, Plastic & Fibreglass Polish
- Carnauba wax
Different users have different preferences. Some artists find a polish paste works better then a polish liquid depending on their piece, and desired finish.
There are a variety of options:
- Wet/Dry sand paper
- Zona wet/Dry Polishing Papers
- Micro-mesh sanding buffing system goes much further up the grits (from 1500 up to 12,000 fine grit). This system is often preferred by jewellry artists.
Most of our resins are hard curing resins. If you're using a resin that can be dented with a fingernail, or softens with body heat, or gets bendy or soft in a warmer temperature, it is not a hard curing resin (the Shore Hardness rating for each resin should be available from epoxy resin manufacturers).
You have to sand to a fine grit first. Ideally you need to get rid of any scratches seen to the eye, before starting to polish. Work down the grits to around 2500/3000 then start polishing. Make sure scratches from previous grit are gone before moving to next grit. Wet/dry sand paper (or zona papers) is ideal for these projects.
You can shape your pieces on a 320 grit disc sander, then 400 grit dry (wear PPE). From there it's all wet sanding 600, 800, 1000, 1200, 1500, 2000, etc. up to 3000.
After sanding use a cutting compound to get out any micro scratches, then a polishing paste. Then polish with a buffer wheel on drill with headlight or choice of polish.
If you want a gloss finish, stop at about 3000 grit, then use polishing compounds for the rest. If you want a matte finish, 1000 grit sanded finish will be fine with oil or whatever finish you're using.
Note: Putting a wax or polishing compound on unsanded resin doesn't really accomplish much, you have to get the finish to a 3000 grit polished sanding. It's worth the work. But it's really not that much work. You just lightly sand it with each grit. And you don't need to spend hours on it with each stage, just enough so that the higher grit removes the scratches from the previous grit. Once you're done sanding the resin will pretty much be back to shiny again, then the polish will gloss it up beautifully.
You can polish hard curing resins with a buffing wheel and a polishing compound. Use a cotton buff and polishing compound appropriate for resins. Get the buff spinning, and use it to pick up compound, then press onto the resin piece. You can use a dremel tool or flex shaft for small projects like charms, but a large buff makes quick work of polishing something larger like a pyramid or coaster. Keep the piece moving. You don't want to buff any one area more than a couple of seconds at a time. You also do not want to press the piece into the buff. Let the buff do the work; let it run over the resin piece or charm, but don't use too much pressure. Go over the entire piece as needed. When done clean with mild soap and water, to remove any polishing compound residue.
When resin is polish sanded, it has such a different feel to it then unpolished resin. It feels like glass and looks amazing.
For a satin finish on wall art or other pieces where high gloss is not desired:
Use 0000 steel wool and rub in a circular motion. Allow at least 36 hours cure (brand dependant) before rubbing the coating, or it may scratch or mar rather then resulting in a satin finish. A good spray finish to put over this, is Liquitex Soluvar Spray Varnish for the satin finish. Some spray varnishes can react with cured resin, but this one has been used by numerous resin artists successfully. If your painting is going to be hung in a spot where light over high gloss is an issue, or someone prefers non high gloss finish, this is a possible alternative solution.