So here I am, 15/20 credits in chemistry under my non-science-brain-ed belt, almost a year of interning at a fantastic regional conservation center (MACC), learning so much, applying most of it and after every shift interning, feeling validation that this is my path. Most of the work I've been assisting with cannot be shared with the public as it comes from private and museum collections. One thing I can write about, though, is compo (sometimes called ornamental composition). Compo is basically a compound of different glues/adhesives and chalk that, when made correctly and molded, makes up most of the fine ornate frames we see today. Here's a great example thanks to a Google image search:
This specific frame, here, is in need of some tlc restoration. The white pieces you can see, where the gilding has chipped off, is the compo (the white is a gesso, layered over the compo, allowing gilding to adhere). To restore this frame, one would take a mold of the pattern with a silicone mold, cook up some compo, allow it to set, and affix compo to frame, re-gesso, re-guild and, voila, good as new!
I needed a project that would satisfy an organic chemistry lab that I had missed. This idea of compo was very interesting to me, so I decided to take a mold and try my hand. The wonderful conservators (in the object lab at MACC, who have been graciously inserting knowledge into my brain for the past 9 months) told me everything I needed to know and were on hand just in case I blew anything up.
So here I am in the lab....
|Two hot plates (living on the edge!)|
|Initial mixing with the chalk|
|Compo in the mold|
|Final product and original mold -- SUCCESS!|
It was pretty satisfying to have a really wonderfully successful product on my first try! The only thing that I didn't do well was not casting the mold quickly enough. The 2-part silicone mold making material set faster than I was ready for. This is why the cracks appeared in the mold, and why they translated onto my piece of compo. The compo piece remained quite flexible for almost a day before it hardened beyond any serious bending. This is one of the wonderful characters of this mixture, it holds a pattern, yet, for hours afterward can be manipulated to fit the desired shape completely.
Not only was this project an amazing hands-on learning experience, but my lab write up (including illustrating the chemical reactions and explaining a knowledge of the properties of the molecules and why they react the way they do together) got full marks! Conservator-in-training success. One more positive step on the way!!