The main considerations when applying your clay are:
- Preparing the barrel
- Height relative to the rest of the pen hardware
- Avoiding distortion
- Smoothing the barrel as much as possible before baking
Preparing the barrel
I don’t have a definitive answer on this. Some people say it’s critical to sand the barrel first — others say that’s only for woodworkers, and it’s better to have the barrel smooth. Others say you should coat the barrel first with PVA glue and let it dry.
I haven’t tried the PVA glue, but I’ve done both smooth and textured barrels and not been able to notice a difference between them.
I do find that when applying canes it’s nice to have the barrel a little tacky, so PVA glue may help with that.
Another solution (which is what I usually do) is covering the barrel with a sheet of clay rolled on the thinnest setting on your pasta machine, and then further rolled thin by rolling the barrel against the table with my hands and trimming the excess clay that comes off the ends. It technically adds a bit of height to the pen, meaning you’ll have to slice a wee bit thinner or sand a wee bit more, but it’s a minimal amount.
Applying clay to your pen
Whether you are covering your pen with cane slices of flowers, etc. like many artists do, or in kaleidoscope patterns like I do, you will need to slice your clay very thin.
For applying cane slices of flowers, etc., I prefer to apply them right on the barrel and design my pen there.
For my kaleidoscopes, I usually do four rows of triangles. I assemble three rows on a piece of waxed paper (like a deli sheet), roll the pen barrel on them by placing it on the middle row and then cupping the deli sheet around the barrel, and then I apply the fourth row directly on the barrel. This is because my canes are not usually the perfect size, and that lets me adjust the final row to be slightly smaller or slightly bigger as needed.
When I’m doing squares, I do the same: one fewer rows than I will have as my final total of rows done on the deli paper, and then the final one applied on the pen, even if it means I have to stretch my final row of squares a little bit.
Height
If you want to make sure your pen is a consistent height with the rest of the hardware, you will want to be aware of how much clay you can add before exceeding the bushings. Some kits, like the Slimline, don’t have much space between the barrel and the top of the bushing, making them a deceptively hard kit to use if you aren’t good at slicing thin slices and don’t want to do a lot of sanding.
Avoiding distortion
Consistent slices are also important: when you’re working on a flat surface you can often cheat with slices that are thicker by shaving them down after joining all your slices together. But on a curved and small surface like a pen barrel, this is much harder or impossible to do.
When you roll the barrel later, slightly-thicker slices will flatten more and push your other slices out of alignment. It makes it very hard to maintain an even-looking kaleidoscope pattern.
Patterns with black lines separating each triangle look even messier, because the wavy lines are much more obvious so consider this when deciding how to design your pen or design a pen that takes advantage of the waviness.
Smoothing the barrel
When rolling the barrel, either use the palm of your hand, or use a flat surface — if you use your fingers, you can introduce distortion and hills and valleys in your barrel. I prefer a clear acrylic block like the sort that is used for rubber stamps that don’t come with a back, because it’s easy to see what’s going on.
As you roll, you’re likely to notice the clay scooting off the end of your barrels — left unaddressed, that will cause your designs to stretch out at the ends of each of your barrels and be much more distorted there.
I pause every 20-30 seconds when rolling to gently nudge the edges back in, so I don’t lose that clay and have distorted ends.
The more work you do now smoothing the better. If you are good at both height and smoothing, you can start as high as ~800 grit sandpaper and do very little sanding.
If you are over height and want to get down to bushing height, you may need to start as low as 60 or 80 grit. Make sure if you’re over height that it’s due to cane slices and not just a thick tube covering, otherwise when you try to sand down to bushing height you may sand right through your cane slices.
Finishing the ends
When I’m done, I used do a final trim around the ends — but too often that meant that the clay pulled away from the barrel or I cut a bit past the barrel end, which looks a bit messy when the barrel is finished.
Now I trim the ends but do a final little roll to let the edges protrude just a bit beyond the edge, and then I sand those down quickly after baking.