Thompson has a muti tier price schedule. Most of the reds yellows and oranges are in the "C" price range. My catalogue is a few years old and the prices on their web store are higher now.
It used to be $25/lb for the standard colors up to $50 for the most expensive (purples) the reds yellows and oranges was second from the top tier @ $42/lb. So it would be cheaper to base coat with less expensive enamels.

Someone else can tell you, but there are probably a number of enamels that work the best for the base coat, maybe better then most of the nicest colors.

I am currently testing the 1030 white with liquid form white and 1030 on the back for the complete cover coat on one fire. That was the one Mr Ellis had recommended to me.

In the Thompson workbook the #1870 has one of the higher flow temps, as compared to the other 1000 and 2000 range enamels.

Some time soon I plan to do the test where you enamel a sheet with the highest temp enamel in your pallet then place little gobs of the enamels you want in ordered rows and try gradually increasing the kiln temp to see at what temp each gob melts. For example start at 1200 and do short timed firings increasing the kiln temp each firing by 25 degrees.

Have a nice day, Marty

Hi Marty, thank you for your reply.  When you write that #1870 has one of the higher flow temps, do you mean it is hard or soft firing or that it is difficult or easy to put a trans color over it?

I had read that reds, oranges, opaque, opalescent, transparent, should not be fired at the highest temps if that is what you mean?  This was in a book called "Cloisonne' Enameling & Jewelry Making" by Felicia Liban & Louise Mitchell, p. 19.

Mary Rose

Hi Mary Rose, the Thompson "workbook" is their technical reference.  It has a lot of terms a normal human being can't pronounce or understand.  

I recomend making a simple chart that has some way of visually understanding the variables of the enamels you plan to use.  Ie some work well as base, some are lower temp, and therfore...  some need to be fired last. 

For example in the kitchen you have to bake the cake before you frost it because the frosting works better cold and is ruined by heat.

There are so many variables.  

On copper they often do a very high temp fire to clear the oxides,  The firescale oxides actually go into the enamel.  But if you over fire painting enamels they will move or disappear.  I guess the reds are like that.

In addition to the book you mentioned there are several others worth getting Linda Darty and Lilyan Bachrach.  

I don't have much experience keeping notes.

M

I fought with orient red for a while until I called Thompson and asked the expert. He said this color likes to be fired super hot and for super long. So I upped my temp and left the piece in longer and I saw a significant difference.

what kind of problems are you having?

Hello, thank you for your reply.  This red does not fire smooth.  I have tried it a high temp, 1500 and a lower, 1300.  It is bumpy and looks underfired.  It also pops off the copper sometimes and does not fire with transp over it.

Mary Rose

Thank you Lindsey.  I read that the reds should be fired for shorter times and at lower temps.  I think we have to make our own adjustments and forget what we read.  I am going to take your reply in consideration and fire this red longer and at 1500.  Is that what you mean by super hot?

Mary Rose

Thank you for your reply.  I have the Bachrach book and the Darty.  I don't much like the Darty book as there are too many photos and she is not thorough on a subject but keeps jumping around.  She does not go deep enough.

Mary Rose

I think the advice you have gotten:  to fire the transparent reds low (1300-1385F/700-750C) and short (depending on the size of your piece) is good.  It has also been said that transparent red looks best over gold though I don't really understand why.   Anyway, my point is that opaques are a whole different story. 

Does anyone have problems with Orient Red #1870 over copper?  What is the ideal temp for this red?  Would there be any reason for firing an opaque over a covering white? 

Thank You,

Mary Rose