The challenge of making a brooch with metal clay is to figure out what type of finding to use.
There are several types of findings that you can embed into metal clay. My preference is to use fine silver components. Most findings have a component that is embeddable and then after firing you add the pin or other components. Here is a selection of some of the brooch findings on the market:
This finding has two fine silver pieces that you can attach with paste, fire then add the pin (after firing). I have found that these findings work well.
Screw type fine silver finding. This finding has fine silver threaded pieces (the round pieces it the bottom of the picture) that you embed into the clay, once fired you screw and glue in the findings (pictured on the top portion). One important thing to keep in mind is when embedding the threaded fine silver pieces it is best that you have the screws filled with the findings otherwise you run the risk of getting clay into the holes (remember to remove the findings before firing. Once fired you screw in the findings. One occasional problem that I have found it that since the threads are fine silver if you are not careful you can strip the threading off making it difficult to screw the findings in place.
Here is an embeddable finding that I have found at Fire Mountain Gems. Again it has two embeddable ends for the brooch that are placed in the clay. Once fired you attach the pin. The only thing I don't like about this is there isn't a springy feeling to this finding (the pin swings freely).Above is the Pin Back from Metal Clay Findings. This one I have not used. It appears to be a nickel pin back which you do not fire and an fine silver clip that you embed then attach the nickel piece afterwards.
In addition to fine silver findings, there are sterling silver findings that are on the market. It is important to keep in mind with these that the sterling silver as it will become brittle if you fire at a temperature that is too high. Generally I will only fire sterling silver at 1250F. I have found that I have difficult time to getting these type of findings to fit securely. I prefer to use fine silver findings and fire my metal clay at higher temperatures. The sterling silver findings are not my favorite options.
Finally, I have been experimenting with embedding regular nickel pin backs into metal clay. I haven't finished all my experiments but hope to elaborate more on this next week.
If you have any brooch findings that you have been using and would like to share. Feel free to let the rest of us know.
Have a great day!