Home Glass Stories Torching verses Polishing when repairing marbles.

Torching verses Polishing when repairing marbles.


Given a marble with a crack ¼ of the way through, a big 1/16” chip and several flea bites.

For discussion’s sake, let’s say it’s a swirl and a person is considering getting it repaired.

For discussion’s sake, let’s not talk about the resale value and let’s say the person wants

to keep the marble for their own collection.


To understand the difference of fixing the marble by torching verses polishing,

let’s give an example: Pretend you had a ball of clay and you poked a pencil into

it ½” deep and made a hole and you lost a bit of clay as you pulled the pencil out.


1) If you rolled that ball of clay around in your hand and rounded the clay back

into a sphere, the clay would fill in the hole but lose only the volume that was originally

lost when you poked the hole into the clay and pulled it out. This is what torching does

to the marble – it allows the hot glass to fill in the hole and you don’t lose volume.

The problems with torching a swirl are: If the color lines are too near the surface,

they usually become misshapen. If the bubbles drift to the surface, the colored bands

will misshapen. Usually, the pontils disappear because they gat melted into the surface

of the marble.


2) If you got a clay blade and took off clay down to the end of where the pencil poked

into the clay, ½ inch deep, and removed the clay as you worked, you’d lose volume of

clay but it would become round again, just a lot smaller. This is what polishing does but

you lose volume as deep as the hole used to be. The problems with polishing a swirl are:

The pontils usually disappear and the opening widens where they used to be. If the

damage is too deep, the colored bands will be affected.


If the marble has deep cracks, torching allows the cracks to turn into small bubbles

and in some cases one can pick them out when they are near the surface. In polishing,

the cracks remain because they are deep inside the marble.


Both methods have their place in repairing a marble if one chooses to have it repaired.