Resin sanding removes slight imperfections in the surface, such as burrs or dust. Achieving a smooth, finished surface on any project, from wall art, a table, or a custom-made ring, takes knowledge and proper tools.
The highly desired, polished shine of your finished surface requires sanding after at least 48 hours of drying time.
Sanding resin properly takes skill. Your objects will turn out beautifully with the right abrasive products, guidelines, and patience.
Types of Resin Sanding
There are two types of resin sanding - wet sanding and dry sanding. Before you decide what materials need to be purchased, consider the desired result if you will mount your object on wood or other porous materials.
Since properly cured resin is an extremely hard material, the proper sandpaper is essential in sanding epoxy resin. Before deciding on materials, you need to determine the type of sanding best suited for your objects.
What Sandpaper Is Best for Resin?
The type of sandpaper that will work best for resin will depend on whether you are wet sanding or dry sanding. Below is a description of each.
Dry Sanding
Dry sanding is appropriate for wood items or ones that will be attached to wood or other porous surfaces.
There are two essential things to note when dry sanding. First, dry sanding epoxy resin produces more dust, so a face mask is required to prevent inhalation. A mask should always be worn when sanding resin since the particles can be toxic and carcinogenic if inhaled. The second consideration is the heat buildup from dry sanding. This heat can actually dissolve the resin, causing a cloudy finish that is difficult to fix.
Depending on the object you are sanding and the desired final finish, you must factor in the grit of sandpaper when purchasing supplies. Sandpaper starts at 60 grit, a very coarse grit, to 2000 grit sandpaper, the finest grit usually reserved as the finishing pass.
So can you dry sand resin? Yes, but dry sanding resin is usually only recommended when you are also sanding wood, such as a wood and epoxy river table. Even then, you should consider wet sanding the parts of the table not in contact with wood.
Aluminum oxide sandpaper is generally a good and affordable choice for dry sanding resin.
Wet Sanding
Wet sanding is usually the recommended option for sanding epoxy resin. The water used in wet sanding washes away the dust immediately. As a result, there is virtually no secondary surface scratching with wet sanding, and the sandpaper lasts longer due to less clogging of residue.
Inhalation concerns are also drastically reduced with wet sanding. The downside of wet resin sanding is the water itself. It can make a bit of a mess, and also damage any wood connected to the resin if you use too much or let it sit for too long.
To wet sand epoxy resin, look for a waterproof silicon carbide sandpaper.
Sanding Resin Tables and Other Large Objects
You can do sanding resin on a table with the wet sanding method, but you must exercise caution with the amount of water used and the length of water exposure.
Wood absorbs water, even through tiny fissures in the resin, which could lead to swelling and possible warping or discoloration beneath the finished surface. Therefore, dry sanding is the preferred method for wood objects.
Any uneven resin application observed should be corrected before continuing in the initial steps of sanding resin on a large object. Doing this will prevent uneven areas or accidental removal of the resin coating during sanding.
Two methods for resin sanding are hand sanding or the use of an orbital sander. The steps are the same whether you use an orbital sander or hand-sanding with abrasive sheets. Most importantly, you'll want to keep the sandpaper clean to prevent swirls, pigtails, or other problems such as scratching or other surface damage.
If the epoxy resin surface has little or no imperfections, you can use a soft sanding pad or sheet over the surface as the starting point. Otherwise, start with a lower grit to remove edges and other imperfections. Sand across and then parallel with each grit, moving continuously with even pressure.
As the resin smooths, move up in grit. A 220 grit will offer a flat finish. A 400-600 grit yields a satin finish, 800-100 is a semi-gloss, and a 1200 grit or higher is for a high gloss sanding finish.
Orbital Sanding Epoxy Resin
You can use an orbital sander successfully for tables and other large objects for resin sanding. An orbital sander allows you to sand a large surface quickly. Sanding epoxy resin with an orbital sander works well for dry sanding for large surfaces.
Orbital sanders are very aggressive in their mode and should be used carefully with attention to the type of disc, pressure, and even movements. Dry sanding epoxy resin with an orbital sander risks dissolving the material and should be carefully performed. Wet sanding is not common with an orbital sander but can be accomplished.
Orbital Sander Discs
If you’re sanding a large area, the best choice for using an orbital sander on epoxy would be hook and loop (Velcro) sanding discs.
Aluminum oxide is one of the most recommended abrasive types for these discs when working with epoxy. You’ll want to find a disc that resists clogging, so we recommend an aluminum oxide disc with gold stearate that significantly reduces the load buildup from sanding.
A plain sanding disc can be used, but you’ll find a hook and loop sanding disc with vacuum holes to be much more efficient if your orbital sander has a vacuum connection. This helps suck away any debris created from sanding that would otherwise clog the surface of the discs, leading to inefficient sanding and also increasing the friction and heat.
You can use a resin fiber disc as well when sanding epoxy resin with an orbital sander over a large area where other types of sandpaper may wear out faster. Though this is not usually recommended because resin fiber discs are stiffer and can take off more material than you might want. If there are already deep scratches or you need to level out the surface, they can be used as a starting point before moving onto higher grit hook and loop discs.
The abrasive surface of most resin fiber discs are either silicon carbide, aluminum oxide or A/O, ceramic, or zirconia. The disc used depends on the type of material under the resin and the resin surface and thickness.
The silicone carbide disc is preferred for use in masonry work and is not a popular choice for resin sanding, even though waterproof sandpaper made with silicon carbide is ideal for hand sanding.
A resin zirconia disc provides for continuous sharpening due to the type of material on the surface and can be too harsh for finer resin sanding.
A ceramic disc is an excellent choice for heat-sensitive material with 24, 36, 60, 80, and 120 Grit available. Some people like to use this for sanding resin with an orbital sander.
The A/O disc would be the most used resin fiber disc for epoxy sanding. The grit doesn’t go as high as hook and loop discs, so this would still only be a starting point for sanding.
Sanding Resin Jewelry and Other Small Objects
When you’re dealing with handcrafted jewelry or other small items, you’ll most likely want it to be perfectly smooth with a polished shine when finished. Small burrs, edges, rough patches, and other minor imperfections can be removed by sanding epoxy resin finishes.
It may seem that a smaller surface is easier and quicker than a table or large surface, but smaller objects take patience and a keen eye for small details not felt by simply running a hand over the surface or eyeing at an angle.
You can use sandpaper sheets for resin sanding of small items. A finer grit paper is used, as the small surface areas should not require coarse grinding to achieve the desired results.
Jewelry
To start, gather your materials - wet/dry sandpaper sheets from 400-1000 grit, a protective mask, and water. Working on a flat, sturdy surface will make the process easier.
Don’t forget to wear your mask so that you don’t inhale any dust. Place the sandpaper on your working surface and dip your piece of jewelry in water. Move the item back and forth over the sandpaper, using caution to avoid over-sanding and removing too much of the epoxy resin.
When working your jewelry over the paper, remember to change direction. Go from north to south, east to west. Dip your piece in the water to remove dust and review the progress. As needed, move to finer grits of sandpaper until the desired surface smoothness is achieved.
As the resin smooths, move up in grit. A 400-600 grit yields a satin finish, 800-100 is a semi-gloss, and a 1200 grit or higher is for a high gloss sanding finish.
Artwork and Other Small Objects
Hand sanding is also the preferred method to protect the surface of other smaller objects, such as wall art and other decor.
The materials are the same - sandpaper with grit ranging from 400-1000 grit, a protective mask, and water. However, a small wooden block is also very useful. You can cut down larger sandpaper sheets for easier handling.
If you are sanding art, wrap your sandpaper around a small wood block, making the paper easier to hold and making a more even pass.
Wet the paper and sand in circular motions, moving back and forth. You should take special care when resin sanding wall art. The resin layer is thinner and aggressive motions or extreme pressure can damage the surface and the materials underneath. Consistent, smooth circles are key.
Change your paper as the grit becomes worn and as the surface smooths, change the grit of the sandpaper to accommodate. As described previously,400-600 grit yields a satin finish, 800-100 is a semi-gloss, and 1200 grit or higher is for a high gloss sanding finish.
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