Making a pen is a more technical process than much of what we do with polymer clay, so there are a lot of places where things can go wrong, particularly when you combine different materials and equipment.
This article is much more complete thanks to the second half of this article on Toni Street’s website that discusses troubleshooting common problems. I’ve written it with my own troubleshooting, but my troubleshooting was definitely helped by what I learned initially from her.
CA glue cracks a few hours after you finish
This happened when I made my first pen using a poor quality CA accelerator or glue. Read the article on CA glue basics for more help.
It can also happen if you generate too much heat in the curing process: for me this was buffing too aggressively.
Toni notes that it could be due to the glue curing too fast. See her page for more tips on that. This hasn’t been an issue for me yet.
CA is white or cloudy in spots
Your pen wasn’t dry, or you used too much accelerator or sprayed it too closely to the pen blank. This can reportedly also happen in very humid climates due to the excess water in the air.
Cracks form weeks/months later
Toni notes that this is usually due to using a non-flex CA. See the article on CA glue basics for more help.
Part of your pen isn’t shiny despite you applying CA everywhere
You sanded below your CA finish and exposed the polymer clay below it. This has happened to me when I tried to sand two barrels at once by going back and forth across both of them: I over-sanded the ends of the barrels in the middle and under-sanded the ones at the far ends, resulting in bare plastic in the middle.
The good news is the solution is simple: just start over applying more CA. You do not need to re-sand all the CA off, just make sure you thoroughly clean and dry the barrels so there’s no dust, water, or oil on them before starting again.
Your CA is very bumpy
You applied too much CA too quickly and it clumped — this will not get better with more CA, you have to sand it back down before you continue.
Check every coat or two when applying it to catch this problem early before it gets worse. You can sand in the middle of your coats and continue applying CA afterwards, just make sure it’s dust- and water-free before continuing.
Your bushings are stuck to your pen after applying CA
If it’s just a thin coat of CA between the bushing and the pen, just twist them apart. If it’s a lot of CA, you applied too much CA or your pen blank was over the bushing height before you began applying the CA, and you need to sand it down more before adding the CA.
There are more tips in the article on finishing a pen with CA glue.
Your CA finish cracked when you pressed your pen together
You didn’t sand off excess CA after removing it from the bushings. See the article on finishing a pen with CA glue.
Your CA finish has pits in it/won’t get smooth
You didn’t apply enough CA to fill in the pits in your original clay finish. Consider sanding more and/or applying more or thicker CA. Medium CA will do a better job filling in pits, which is why I always end with at least 1-2 coats.