Hi Ron,
As you know, there are 2 basic types of enamel: hot enamel (which actually is the only real enamel), and so called cold enamel, which is NOT enamel but some sort of epoxy resin that mimics enamel. The difference between these two type is that you need to bake the first one at high temperatures that can range from about 500 up to about 850~900 degrees celsius depending on the enamel itself (different colors melt at different temperatures), while the second one is applied quite simply at room temperature and polymerizes.
As we all know, real enamel is fragile, but is also very resistant to scratching for instance as it is glass. Cold enamel is much less fragile (I have yet to see accidentally damaged cold enamel), but scratches very easily (it is plastic resin). That is actually an easy test to conduct "in the wilderness" when no black light nor other equipment is available to determine the genuineness of an enameled item (if the seller KNOWS that his piece has been reenameled but wants to sell it to you as genuine, he usually turns green when he sees you pull a pin out of your pocket to conduct a scratch test
)
When it comes to repairing damaged enamel, there are two basic considerations:
. do you want to repair the piece so that it looks better, without trying to pass it as original enamel, or
. do you want to repair the piece with an intent to dupe people later on
If your purpose is along the lines of the first question, then simply patch the damaged enamel with cold enamel, it will be close enough. If you are inching toward the second reason, then it is a much more involved and tricky process.
No partial real enamel repair will ever be perfect and uniform, so 99.9% of the time the repair can be detected; the most difficult thing to do in enameling is matching colors. For instance, there are over 650 different shades of blue enamel available commercially, to which you can also add those custom made. You also need to realise that the enamel powder is NOT the same shade as the fused enamel; for instance, red enamel powder is usually white or off-white. And glass enamel has a slightly different color depending on the base metal; the processing of the base metal can also have a direct influence on the final color.
As you can easily understand, this means that you have little possibilities to match precisely and accurately the final color of your repair with that of the original enamel. So, to make the repair undetectable (to a higher or lesser degree), you must therefore entirely strip the piece of its enamel using some special alchemy that I will not divulge publicly so as not to encourage new vocations
. Once your piece is cleaned of all enamel and/or undercoat, you simply re-enamel it as if it were a brand new piece. This way, your final product will have consistent enamel throughout.
I will not disclose the details of the actual process as I believe that there are already enough problems with fakes and alterations without providing a handbook of the perfect kitchen enameler. On the other hand, I'll be happy to answer all general type of questions, if any.
Marc
