Sandpaper

Though it is not necessary to sand your cured polymer clay creations-in fact, sometimes you may want to leave things just as they are-sanding is certainly part of the process for many polymer clay artists and hobbyists. The following are few general guidelines for sanding polymer clay:

Use wet/dry sandpaper.

Most people use wet/dry sandpaper (sandpaper that can be used either with or without water) to avoid inhaling dust during sanding. This type of sandpaper is black or grey, not brown or tan, like regular sandpaper. The package will specify the type, so there should be no confusion. You can find higher-grit sandpapers in some hardware and hobby stores or in the automotive departments of stores like Walmart and K-Mart. If you can't find a specific grit or the very highest grits, you should have better luck at an automotive parts store or on-line.

Because the paper comes in fairly large sheets-larger than you'll generally need, you'll probably want to cut the paper into small pieces (using an inexpensive pair of scissors, since cutting sandpaper may damage them). As you go, label each piece according to grit, using a permanent marker. Later on, this will make it much easier for you to identify different grits.

Use multiple grits properly.

Sandpaper comes in different grits. The lower the grit number, the coarser the paper; the higher the number, the finer the grit. Always start with the lower grits and you're your way up, step by step, to the higher grits. It's best to not skip a grit (i.e. don't go from 400 to 1000, but go from 400 to 600 to 800, and then to 1000). Skipping grits can leave gouges on the clay. It is also advisable to stick with one brand of sandpaper. Different brands may not have interchangeable grits. For instance, the 600-grit paper from one manufacturer may be the same as the 400- or 800-grit paper from another source. You could unintentionally be skipping grits of even going backwards on the grit scale.

Deciding which grits to use is a matter of personal preference. Experiment until you find a routine that satisfies you. You should usually start with a grit that looks and feels like the texture of your clay surface. This may be 220 or 320. Some people start with 400. If you spent considerable time smoothing the clay before you cured it, 400 may be fine, but if your clay surface is rough or uneven, you'll get better results if you start with a lower grit. Some people work their way up to 1000, 1500, or even finer grits. Others are satisfied with the finish left by 600-grit paper. It depends on what you like and your future plans for the piece. If you plan to buff a translucent piece to a high shine, then sanding up to 1000 or higher will probably help.

Understand sandpaper grit scales.

It is important to note that there are different scales of sandpaper grits. The two you'll most likely see are CAMI and ISO/FEPA. The two scales grade sandpaper differently, so a P800 (FEPA) is about the same as 400 (CAMI). Here's how this can affect your work: Say you've just finished sanding a piece of with 400 (CAMI) grit paper. You move on to 600 (CAMI), then you pull out your P800 (FEPA) paper. You think that because you're moving slowly up the scale in numbers, you're going to get the very best results, but actually, by using P800, you'll be undoing all the work you did with the 600 (CAMI) grit paper! This is not only wasteful, but it can also mar the finish of your clay. Keep this in mind when purchasing and using sandpaper. There are links to sandpaper grit comparison charts below.

Sandpaper Grit Comparison Charts:

Wikipedia: Sandpaper
http://en.wikipedia.org/wiki/Sandpaper

Online Industrial Supply
http://en.wikipedia.org/wiki/Sandpaper

Homestead Finishing Products
http://www.homesteadfinishing.com/htdocs/gritchart.htm

Sand with water.

Some people say that soaking your sandpaper for five minutes before beginning to sand will prolong the life of the paper. You may sand under running (or trickling) water or in a shallow bowl of water. Some people like to add a drop or two of liquid soap to their sanding water to make it a little "slippery" and to facilitate moving the sandpaper over the clay. It is not necessary that you submerge the clay and paper the entire time, but you'll want to dip them down into the water frequently to prevent the paper from becoming clogged with residue. Periodically change your sanding water.

Alternatives to Sandpaper

There are a several items that can be used in addition to or instead of sandpaper, including the following:

Sanding sponges
Fingernail files, emery boards, sanding sticks
Steel wool
Scrubbing pads (the type used for dishes), Scotch-brite pads/sponges
Scrubbing pads (the type used for woodworking)
Facial scrub pads
Sanding film (such as Flexible Film Sandpaper)
Sanding cloths (such as Micro-Mesh)