ABW Research "Labs"
When we started ABW, all sorts of fabric/textile/yarn workers seemed to agree that special embellishments were, for the most part, not expected to go through the wash and dry cycle. And, for the most part, neither were the wearables they made expected to do so either.
However, after handling the buttons I made for a while, I got curious. So, I decided to sew some of my buttons onto shirts I wear all the time. For two reasons: I liked them, and they were good for advertising!
The result is that I, Clair, have officially appointed myself head of and sole worker in the ABW Research "Lab". While I think, as I said above, folks expect fine art buttons to have cautions applied to them, I have been doing a little investigating. So, take this report as fact, which it is. But also take it with a grain of salt, as most fabric workers I've spoken to, expect to treat special buttons differently.
Lab Report #1 - December, 2009: Washing Survival Tests
Caveat: The following report pertains only to buttons I have made, which are not thick ones, and to buttons that don't use alcohol inks in the surface treament. (I am about to sew on a button where the entire surface has alcohol ink on it. Report will follow in a few weeks.) A few buttons have cautions on them, denoted by a small 'x' immediately after the button's name. I'm gradually going through our database of buttons specifically to double check on whether a button needs an 'x or not. Generally the caution will also apply to very large, thick buttons, where the weight of the button itself may be a factor in how well it behaves under harsh circumstances.
My best suggestion is, for the few of you who might want to "buttonize" a fabric that will be treated like a pair of jeans, to call me when you see a button that might work. I'll pass it or fail it for you!
I have sewn my buttons onto various shirts of mine that I wear often. Because they are worn frequently, they are also washed frequently.
Full Disclosure
I have never in my life sorted a load of laundry; when my laundry basket is full (enough for one load) its contents get washed and dried all at once and all together. And, all my clothes are cotton.
Results So Far
I started this process in late October. Several shirts have been laundered many times since then. This is a photograph of
three of the shirts today after about 4-6 wash/dries each. I can see no ill effects at all.

The red shirt is heavy flannel,
the other two are heavy duty Levi cotton shirts. Here's a close-up of one of the buttons above. It was the second
button that went on a shirt, but it's a favorite shirt, so I would guess this one's been through the wash/dry cycle about 6 times.
Button Materials
The surface material used on these buttons is Pearl Ex on the left two big buttons and the very small one; I used a bit of alcohol ink and acrylic on the weakly decorated gray button. (The alcohol ink amount was so small that I don't consider it a proper test of the ink.) The gray button was an experiment with the ink and acrylic, both applied extremely lightly. The clay I use 99% of the time is FIMO Classic. Some buttons may also contain, or be entirely of, Cernit clay. Each of the large buttons is about 1/8" thick. The small button on the red shirt cuff is very, very thin. It would not handle any stress at all, for instance, as the waistband button on a pair of slacks. But, it's all right where it is. Consequently, none of the ABW buttons for sale are this thin.