I used a butane torch to smooth a chip in a pyrex bowel. It seemed to work. The chip was no longer sharp. I let it cool and then tool it to the sink to wash. As soon as the water touched the bowel, it cracked the entire bottom out of the bowel. So...I cannot recommend using flame to smooth a chip in Pyrex!

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On 12/29/2022 1:45 PM, StevoMT wrote:
> I used a butane torch to smooth a chip in a pyrex bowel. It seemed to
> work. The chip was no longer sharp. I let it cool and then tool it to
> the sink to wash. As soon as the water touched the bowel, it cracked the
> entire bottom out of the bowel. So...I cannot recommend using flame to
> smooth a chip in Pyrex!
>
May have worked if you brought the entire bowl up to some fairly high
temperature, more than your oven.About 850 and cool for hours.

On 12/29/2022 1:18 PM, Ed Pawlowski wrote:
> On 12/29/2022 1:45 PM, StevoMT wrote:
>> I used a butane torch to smooth a chip in a pyrex bowel. It seemed to
>> work. The chip was no longer sharp. I let it cool and then tool it to
>> the sink to wash. As soon as the water touched the bowel, it cracked
>> the entire bottom out of the bowel. So...I cannot recommend using
>> flame to smooth a chip in Pyrex!
>>
> May have worked if you brought the entire bowl up to some fairly high
> temperature, more than your oven.About 850 and cool for hours.

Heating one spot in glass until it starts to melt will create stresses,
which your instructions may remove. I used to do some scientific glass
blowing with Pyrex and everything made went into an annealing oven,
which does just what you said. When using the pieces an end would be
cracked off a cylindrical piece and the crack could be fused back
together leaving uniform stresses around the cylinder.

Pyrex used to be a particular borosilicate glass. Pyrex is a brand name,
and the owner now uses the name for a different kind of glass, not as
low expansion.

Use something like silicon carbide paper to smooth a sharp edge.

On Thu, 29 Dec 2022 21:45:43 -0600, bud-- posted for all of us to digest...

>
> On 12/29/2022 1:18 PM, Ed Pawlowski wrote:
> > On 12/29/2022 1:45 PM, StevoMT wrote:
> >> I used a butane torch to smooth a chip in a pyrex bowel. It seemed to
> >> work. The chip was no longer sharp. I let it cool and then tool it to
> >> the sink to wash. As soon as the water touched the bowel, it cracked
> >> the entire bottom out of the bowel. So...I cannot recommend using
> >> flame to smooth a chip in Pyrex!
> >>
> > May have worked if you brought the entire bowl up to some fairly high
> > temperature, more than your oven.About 850 and cool for hours.
>
> Heating one spot in glass until it starts to melt will create stresses,
> which your instructions may remove. I used to do some scientific glass
> blowing with Pyrex and everything made went into an annealing oven,
> which does just what you said. When using the pieces an end would be
> cracked off a cylindrical piece and the crack could be fused back
> together leaving uniform stresses around the cylinder.
>
> Pyrex used to be a particular borosilicate glass. Pyrex is a brand name,
> and the owner now uses the name for a different kind of glass, not as
> low expansion.
>
> Use something like silicon carbide paper to smooth a sharp edge.

+1

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Hiram

I had a relatively new set of French White casseroles. I found out the hard way (I cut myself, picking up the lid) that one lid had a sharp edge on the rim underneath. I don't know how; if it came that way or if I splintered off a piece of the glass. Anyway, after reading a suggestion that sanding would work, I pulled out a painting sponge/sander and worked on it for a couple of minutes. The sharp edge dulled right away and it looks like it will be safe to use now.

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