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I want to make frit from some old, failed pate de verre pieces by quenching the glass. In the archives I saw the idea of placing glass in a stainless steel bowl when firing it to 1000 degrees. Do you need to spray the bowl with something first to prevent the glass from sticking? Thanks

Not at 1000F.

Thanks. I guess I should have also asked, will the bowl spall? I'm wondering how much of a mess I want to deal with.

It shouldn't be a problem, lots of people do it this way.

The bowl will turn funky colors but it shouldn't spall. I often fire float to 1200 and sometimes black iron from the bowl does stick to the glass, but usually it doesn't. I never kiln wash the bowl. I do have a pair of kevlar gloves for this. A plastic bucket of water, 2/3 full, is fine though. One big caveat is don't wear polyester clothing, it can melt. Where I live, I usually wear polar fleece in the winter and this can easily melt. 100% cotton or wool is fine.

Understand that quenching essentially tempers the glass. This makes it harder to break up in smaller pieces than the ones that originally form, however when you do break them up, they tend to break with many fines. Companies that make frit sometimes quench, but often they prefer to crush annealed or unquenched glass. A lot depends on what kind of tools you have for making frit, and what sizes you prefer.

I disagree.

I've made a lot of frit and my preferred method is to quench the glass first. I use a SS bowl and heat about 3 - 5 lbs of glass to 1000 - 1100 degrees. Turn off the power and grab the bowl with large pliers. Welding gloves are sufficient. Dump the glass into a bucket of water. I prefer to dry the glass before breaking it apart.

The glass pieces will be crackled but most will be unbroken. At this point you can break them apart with your fingers however it will be rough on your skin. I then mash them in a crusher. They break up easily.

In my experience, frit made this way is more granular than the frit you get when you mechanically crush it without quenching first.

Jim "The Hobbyist"

The Hobbyist wrote:I disagree.

I've made a lot of frit and my preferred method is to quench the glass first. I use a SS bowl and heat about 3 - 5 lbs of glass to 1000 - 1100 degrees. Turn off the power and grab the bowl with large pliers. Welding gloves are sufficient. Dump the glass into a bucket of water. I prefer to dry the glass before breaking it apart.

The glass pieces will be crackled but most will be unbroken. At this point you can break them apart with your fingers however it will be rough on your skin. I then mash them in a crusher. They break up easily.

In my experience, frit made this way is more granular than the frit you get when you mechanically crush it without quenching first.

Jim "The Hobbyist"

Jim, whatever works for you... I have spoken with people at both Bullseye and Thompson enamel about their frit making process. Both companies told me they prefer non-quenched glass. So, as I said, it is a lot about your equipment.

Quenched glass does produce a granular frit. Tempered glass breaks with square edges. You can run your hand through a bucket of quenched frit and come up bloodless. I've been doing a lot of this lately. It is a lot more work for me to break up broken tempered float than it is to clean, cut, and clean it.

I'm sure the reason Bullseye and Thompson make frit that way is because quenching would add extra cost to the production. It's doubtful the public would pay extra for granular frit.

I have made frit both ways and I prefer the granular. For my work it is much easier to manipulate. I also don't like being stabbed by the needlelike pieces.

Jim

The Hobbyist wrote:I'm sure the reason Bullseye and Thompson make frit that way is because quenching would add extra cost to the production. It's doubtful the public would pay extra for granular frit.

I have made frit both ways and I prefer the granular. For my work it is much easier to manipulate. I also don't like being stabbed by the needlelike pieces.

Jim

My original assumption was that they would quench directly from the furnace to make frit, because it eliminates a forming step. At Thompson they told me that they do some this way, but they find it easier to crush non quenched glass. The quenched glass is tempered so is more resistant to breaking down. By the time the glass falls through an 80 mesh screen, there isn't all that much difference in particle shape. Bullseye has plenty of ends of sheets and broken sheets, so it makes a lot of sense to use that for frits. They told me that they do not quench to make any. Both companies use sophisticated crushing and sizing machinery. These stories are not particularly recent ones.

I agree with you that it is easier in the studio to deal with quenched frit. However when I put it in my Steinert crusher and smash it with the sledge hammer, the result usually has a lot of fines, which I don't love. Consequently I have developed techniques that utilize the size frits I get by breaking tempered glass and using the shape pieces I get without a further crushing step. It makes sense to find a path of least resistance for your facility.

Quenched is best for us, the glass user, but Bullseye can't deal with the wetness. They need to be able to size the pieces as part of the crushing process. Also, the moisture messes with the magnet they use to remove any metal fines from the crushers.

Once again, I would just like to say THANK YOU SO VERY MUCH! I have been all over the internet and You Tube (couldn't remember the word "quenching") and at last you have given me the tools here that I was seeking.
Bert you remain my eternal hero.

In gratitude!
Jolinda Marshall

Hello neighbor ,

I bought an old SS MILK bucket and make Frit. Ann nye posted a video how she (well her husband) does it,

https://m.youtube.com/watch?v=p3mpWIv08lc

Enjoy the rain we've been getting!

Shereen

When I make quenched frit, I heat the glass in a kitchen stainless steel bowl that fits in the kiln. Then I remove it with hitemp gloves and dump the glass in a 5 gallon plastic bucket of water. Big drama. The plastic bucket is not effected in any way. This is funny. I have a steel frit crusher, but the way I use it is to throw it in the bucket of quenched glass after it has been drained. This manages to break up the chunks pretty decently.

Someone posted (I can't remember where) a warning about not using galvanized buckets for quenching glass. I'm assuming this was due to potential zinc contamination of the glass. Would this really happen? If so, could one paint the bucket to prevent said contamination?

nbobb wrote:Someone posted (I can't remember where) a warning about not using galvanized buckets for quenching glass. I'm assuming this was due to potential zinc contamination of the glass. Would this really happen? If so, could one paint the bucket to prevent said contamination?

Heating zinc creates toxic fumes. Don't do it.

Would someone be able to share again how to tell that your stainless steel object (bowl, wok, form, etc.) is or is not galvanized? I came back from Good Will with a Martini shaker that looks promising...Of course, it's tempting to keep it for making martinis, but I prefer wine...LOL

Studiodunn wrote:Would someone be able to share again how to tell that your stainless steel object (bowl, wok, form, etc.) is or is not galvanized? I came back from Good Will with a Martini shaker that looks promising...Of course, it's tempting to keep it for making martinis, but I prefer wine...LOL

Every martini shaker I have ever seen is indeed stainless steel. Decades ago, I bought a floral former from a glass wholesaler for $18 and change. Then I bought the identical martini shaker at a restaurant supply for $3 and change. When I say identical, I mean down to the brand name.

It is actually OK to heat a galvanized bucket as long as it is filled with water. It can't get too hot that way. Without the water, then you are in danger.

I used to put on a couple of lobster feeds for 200 people every September. We had a couple 500,000 btu propane burners, and galvanized steel tubs with wooden lids. We could fill those tubs with cold water, add some salt water, 2/3 full, and bring it to a boil in 15 - 20 minutes. We would then toss in 40 lobsters for 12 minutes, pull them out and start again. We had 2 of these rigs going, so in a half hour, we could cook 200 lobsters. I once asked the University of Maine extension service if this was an acceptable cooking practice. They told me that it was. They said, galvanized tub: not toxic, Aluminum pot: toxic. We were doing this on an offshore island, not far from the port where 1/6 of all the lobsters in Maine are landed. BIG FUN!

Thank you Bert! My Good Will martini shaker price was $3.00 as well SCORE! I'll get on with the experimentation...

And coming from the Midwest, where burgers & pizza take center stage, your lobster feeds sound heavenly!

I did wonder about your warning not to use a galvanized bucket to quench glass since many people cook in them. From what I've heard, zinc vaporizes at around 1600 F, so heating glass to 1000-1200 then dropping it into a galvanized bucket with water in it would be nowhere near 1600F. And even if fumes were released they would dissipate into the air if you were outside (where I would be).