Sunday, August 08, 2010

Metal Clay Pastes: Overlay Paste

There are numerous versions of paste which you can use when working with silver metal clay; this can make things confusing.

The types of pastes are:
  • Paste (watered down clay used for attachments, repairs and to coat organic materials)
  • Syringe paste (a thickened paste that comes in a syringe - I discussed this one several weeks ago).
  • Overlay Paste (I will explain this one today)
  • Oil Paste (I will discuss this one next week)
The most common and essential paste is the regular paste that is used to fill cracks, attach pieces and to cover organic shapes (such as leaves) with layers. It can be purchased or you can make your own with your reclaimed pieces of clay by adding water and allowing them to sit. I have a series of paste jars in varying consistencies on hand on my work bench.

Today I want to discuss Overlay Paste. It is a product unique to the Art Clay Brand.

Overlay Paste
Overlay paste originally made to bond to ceramics in order to paint on ceramics. It has since been recognized that it can to bond to glass as well and be used for repairs and attachments on fired metal clay. One of the features that makes it unique from Oil Paste is that its minimum firing temperature is lower, at 1200F; therefore allowing low fire repairs.

I have used the Overlay paste both on ceramics and glass and to make repairs. Here is what I have found:

In order to bond Overlay paste to ceramic or glass be sure to clean the surface of all oils. (I have found that using rubbing alcohol works fine for this purpose). The other important trick is to apply a thin layer to the surface. (In one of my early experiments I have been misinformed and was was told to put on two thin layers - this did not work and the layer ended up being too thick and I was able to flake some of it off.) I have found that a thin layer (the consistency of milk works best).

In regards to repairs I have had mixed success. I am of the mind to fire most of my metal clay at around 1600F for 2 hours but there are times that this isn't possible as in the case of adding sterling to your metal clay. I recently made brooches with sterling findings on them and decided to fire the piece first at 1600F without the findings then add the findings to the already fire pieces with overlay paste. Sadly, I had mixed success. I have three findings attached with a fourth one that still won't adhere properly. I am not certain as to why (kiln temperature, oil on the findings, product, or user error????). I am still figuring it out. (If I do figure it out I will let you know)

There are other uses for Overlay Paste. One is to use it to add silver accents to fired copper clay. I have done this only once and it worked quite well.

Another use is to add overlay paste onto fired silver to prep the surface to add the Gold Paste. I was unable to find my specific notes on how to do this to add. My recollection is that you add a thin (milk consistency) layer of overlay past where you want to add gold (on an unpolished but fired piece of silver clay). You let this layer dry then you add your gold paste. (Sorry I don't have more details, if I find the info, I will post it later).

Overlay Paste can be a useful addition to your metal clay products you use, especially if you want to add silver to glass or ceramics. Of course, I should note that regular paste will often stick to glass or stones as well, especially when you don't want them too. Overlay Paste is made to be that much stickier and will work better than just plain paste.

Next week, I will be talking about Oil Paste both homemade and Art Clay Oil Paste.

Stay tuned.


1 comment:

Seavbeach Designs said...

Heather I have some questions. First I want to use Overlay paste on a stamped piece of fired Coppr clay. Will it take away the details of the stamping underneath? Secondly did you fire in carbon?