Prevention of Spikes at Corners

Often, after fusing rectangles we are left with sharp points at the corners. How can we prevent it?

 

Nipping corners off rectangles, especially opalescent and the underlying base pieces, is a standard practice to avoid sharp points on corners of a finished piece.

The principles of this relate to how glass contracts when cooling.

The glass expands in the fusing and then contracts on cooling. The hot glass can attach to a rough bit on the paper or shelf and be stretched in the cooling. This results in a sharp needle point.  There is more glass at the corners than at the sides to contract. This leads to the creation of more sharp points at the corners.

Only a small portion of the corner needs to be nipped off as shown in the first picture. It will not affect the dimensions of the piece. It will not affect the appearance of the corners. Except, of course there will be no sharp points.

The fix is simple. Nip a bit of the corner off before assembly. Also no more than 10 minutes at top Temperature should be needed.

Full details are in my eBook Low Temperature Kilnforming.