Tuesday, August 12, 2014

How Are Overlays Used In Stained Glass Projects?

Overlays are used in stained glass projects when the artisan wants to create a special effect, add more detail, create a different dimension to a project, or just to create more interest in the finished product to make it unique.

Tiffany style lampshades frequently use overlays in their design to enhance the overall beauty and
intricacies of the finished shade.

Generally, overlays are fabricated from copper or brass sheets and are then added to a project to create the desired effect.

Overlays can make a single piece of stained glass look like several pieces of glass soldered together or they can be used to create solder lines that look like they end in the middle of a glass piece.

Overlays are often used in stained glass projects to create details that would normally be impossible or at the least, extremely time consuming to create using pieces of cut glass alone.

Copper is the best medium for creating overlays because of it's malleability.

Depending on what you want to achieve; overlays can be made from large adhesive backed copper sheets, standard copper foil tape or on larger projects, from thicker copper sheets.

ADHESIVE BACKED COPPER SHEETS

Adhesive back copper sheets are by far the best option for covering an entire glass piece and creating an intricate design overlay.


To do this, use the piece of glass you are going to cover as a template and then cut out it's outline from the copper sheet with an Exacto knife or a good pair of scissors.  Do not peel off the backing until ready to use.

Next, trace or freehand the design you want to use directly on to the copper sheet and cut out the places where you want the stained glass to show through with a sharp Exacto knife.

Now all you need to do is peel off the backing and burnish the overlay on to the glass surface.

An alternate method that is sometimes used is to first peel off the backing from the copper sheet and apply it directly on to the stained glass you used as a pattern.

Then trace your design on to the copper and cut out the areas you want the glass to show through with a sharp pointed Exacto knife.

The problem with this method is that you will dull your knife blade much more quickly and if you press too hard, you can unintentionally score the glass beneath.

  • If your glass piece is small enough, you can cover the entire glass piece at once by making the overlay large enough to wrap over the glass edge and around to the back.  
  • You can also cut the overlay to fit the glass face, apply the overlay as indicated above, and then foil the edges of the glass piece like you would with any other project. 
  • Or; you can first foil the piece as you would any other project and then apply the overlay, making sure that the edges are met and covered enough for the solder to hold them together. 
Depending on the size of your project, the design of your overlay and the overlay material that you are using; all three methods have their place and work well.

Be careful when making overlays from foil tape or thinner sheets of copper.   They can distort and warp if you try to tin the overlay or solder it before attaching it.

Do this during assembly, not before.

Also don't use a lot of flux when soldering or tinning overlays.  Excess flux can seep under the overlay and cause the adhesive to lift, especially when using thinner copper overlays.

STANDARD COPPER FOIL TAPE 

You can use a piece of standard copper foil tape to create an overlay directly on the face of a stained glass piece.

Apply it to the front of the glass the same way you would foil the edge of a piece of glass.  Just don't apply too much pressure when burnishing or you could crack your glass.

The copper foil tape when burnished, trimmed and soldered makes a solder line of the surface of the glass that can be made into interesting designs.

When using opaque or semi-clear stained glass, you may want to duplicate the pattern on the reverse of the piece you are working on, especially if the piece is a stained glass suncatcher or other project that can be viewed from both sides.

This method is often used to make a single piece of stained glass look like two or more pieces soldered together.

It is also used to create a veined effect on leaves, flowers, bird feathers, fish scales, bird beaks and legs, etc.

THICKER COPPER SHEETS

Overlays made from thicker copper sheets are usually pre-tinned and attached to the piece during final assembly.

Because copper sheets are thicker, they are less likely to distort or warp during the tinning process. However, they also require more heat for the solder to adhere during the tinning.

Rather than soldering them after they are fully in place, it is best to pre-tin thicker gauge copper overlays before placing them on the sheet of stained glass to minimize the chance of heat fracture.

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