I'm new to enameling, so look for info from others too. This having
been said, copper is an ideal medium for enameling, so it would not
be a good medium for a trivet or firing rack. Find a supplier of thin
stainless steel sheet to make your own. Look for a welder's supply
company in your area.
Re safety glasses - if you are using a kiln, definitely YES! here
are two links.
The first is to a website I found which is a lampworkers' forum.
Please pay particular attention to the posts by Mike Aurelius, who
owns a company which makes safety glasses for lampworkers. On this
discussion website you can learn the characteristics of the lenses
needed to protect your eyes while using a kiln.
The second link is to Mr. Aurelius' company, where you could buy his
safety glasses. The glasses seem expensive. but you only have one
pair of eyes, and you use them a lot.... not trying for wry humor
here but for sincere concern. If these glasses are out of your reach,
consider getting welding glasses for the times when you are opening
and closing your kiln door.
Hope this helps,