Open Pontil worked by scraper?

[Dug]

Just finished tumbling an open pontil food jar. Not sure why I didn't notice before, but this bottle has about five grooves left in the base across the open pontil scar.

As a WAG, was this done by the bottle maker to score off excess glass from the scar while the bottle was still hot?

 

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[NJKLAGT]

You've got all the weird bottle bases!

 

[Dug]

You've got all the weird bottle bases!

Seems to fit my personality. LOL.

 

[Harry Pristis]

Just finished tumbling an open pontil food jar. Not sure why I didn't notice before, but this bottle has about five grooves left in the base across the open pontil scar.

As a WAG, was this done by the bottle maker to score off excess glass from the scar while the bottle was still hot?

Just what is your theory about how the gaffer held the hot bottle while he scraped the bottom?

 

[Dug]

Just what is your theory about how the gaffer held the hot bottle while he scraped the bottom?

Gingerly?

Seriously, I have no theory. I merely posted a question. I posted it in hopes that someone in the know might be able to explain the creases, grooves, lines, or whatever the proper name for the marks are.

Just looking for wisdom.

 

[Plumbata]

Hah, yet another mysterious item, nice work Dug!

My theory is that the grooves were carved into the base of the mold on order to purposefully make the surface of the base of the bottles uneven, perhaps so the empontiling process would go more smoothly (more surface area and divots for the ring of glass to stick to, so fewer might accidentally fall off and break during production), or perhaps for some sort of structural benefit (somehow minimizing the base-cracks often seen in OP bottles, which would spread or cause complete failure when piping-hot foodstuffs were being packaged). Those lines go underneath the pontil mark so were not done afterward.

 

[Tpmetal]

Hah, yet another mysterious item, nice work Dug!

My theory is that the grooves were carved into the base of the mold on order to purposefully make the surface of the base of the bottles uneven, perhaps so the empontiling process would go more smoothly (more surface area and divots for the ring of glass to stick to, so fewer might accidentally fall off and break during production), or perhaps for some sort of structural benefit (somehow minimizing the base-cracks often seen in OP bottles, which would spread or cause complete failure when piping-hot foodstuffs were being packaged). Those lines go underneath the pontil mark so were not done afterward.

So I am a glass artist and plumbata may be on to something. Though usually a sand pontil(bit of glass rolled in sand to make less secure connection to prevent chipping) was used before marring the surface like that. Could have been a gaffers solution who didn't know about these techniques. These lines look smooth like it happened in the hot process(correct me if I am wrong about the smoothness). Could also be from a few other things, like mould imperfections, possibly a damaged mould, maybe glass got stuck into a mould (mould too hot) and these are the scrape marks from a tool used to scrap out the mould? Could also have made a mistake going into the mould or closing it around the piece that created dents/folds on the surface. Really hard to say how it happened, glass can be a fussy beast sometimes.

 

[Dug]

Hah, yet another mysterious item, nice work Dug!

My theory is that the grooves were carved into the base of the mold on order to purposefully make the surface of the base of the bottles uneven, perhaps so the empontiling process would go more smoothly (more surface area and divots for the ring of glass to stick to, so fewer might accidentally fall off and break during production), or perhaps for some sort of structural benefit (somehow minimizing the base-cracks often seen in OP bottles, which would spread or cause complete failure when piping-hot foodstuffs were being packaged). Those lines go underneath the pontil mark so were not done afterward.

Very good observation Plumbata. The lines are deep but smooth. Had I looked a little closer and seen that the lines went underneath the scar I could have saved myself a red@ssing from Harry LOL. it's all good.

Now for my next trick...